abdomen [AB-duh-men]

The part of the body between the chest and the pelvis. It includes the stomach (with the lower part of the esophagus), small and large intestines, liver, gallbladder, spleen, pancreas, and other organs.

abdominoperineal resection [ab-dah-muh-no-pair-uh-NEE-uhl re-sek-shun]

also called AP resection or APR. A type of surgery for rectal cancer, in which 2 cuts are made, one in the abdomen (belly), and the other around the anus. This allows removal of the anus and tissues around it. A permanent colostomy is needed after this surgery. See also abdomen, anus, colostomy, rectum.

ablate [ab-late]

To remove or destroy the function of an organ or body tissue. See also ablation.

ablation [a-BLAY-shun]

Treatment that removes or destroys all or part of a cancer; can also be used to remove or stop the function of an organ. For example, removing the ovaries or testicles or taking medicines that cause them to stop making their hormones would be called ablation. Besides surgery and drug treatment, other ways of ablating body tissues and tumors include extreme heat, freezing, and chemicals. Also called ablative ( ab-LAY-tive) therapy.

abscess [ab-SES]

A collection of pus in tissues, organs, or other parts of the body.

actinic keratosis [ak-TIH-nik KAYR-uh-TOH-sis]

A rough raised area of skin that can develop after a lot of sun exposure. They are benign (not cancer), but over time a few can develop into squamous cell cancer. It is often found on areas of the skin that are frequently exposed to the sun like face, scalp, neck, forearms, and the back of the hands. Also called solar keratosis.

active surveillance [AK-tiv ser-VAY-lents]

Watching a patient’s condition closely without giving them any treatment. During active surveillance, certain exams and tests are done regularly. If there are changes to these test results, treatment may be recommended. Active surveillance may be part of a treatment plan for certain types of cancers like prostate cancer.

adenocarcinoma [A-deh-noh-KAR-sih-NOH-muh]

Cancer that starts in glandular tissue. Glandular tissue makes and secretes a substance, such as in the breast (milk) or in the gland cells of the prostate (seminal fluid).

adenoma [A-deh-NOH-muh]

A benign growth (not cancer) that starts in glandular tissue. Glandular tissue is tissue that makes and produces a substance. For example, glandular tissue in the ducts or lobules of the breast produce milk, and the gland cells of the prostate produce seminal fluid.

adenomatous polyp [ad-no-muh-tus or ad-uh-NO-muh-tus pa-lip]

A benign (not cancer) growth of abnormal glandular cells. These can become cancer, so they are usually removed when found. For example, 3 types of adenomas that can grow in the colon are tubular, villous, and tuberovillous. In each type, the cells are arranged differently, but there is some overlap so that an adenoma can have both tubular and villous features. See also glandular cells, hyperplastic polyp, inflammatory polyp, polyp, tubular adenoma,villous adenoma.

adhesions [ad-HEE-zhunz]

Scar tissue that forms after surgery or injury. If the scar tissue tightens, it may bind together organs that are normally separate. This can sometimes cause problems, for instance, if there is partial or total blockage of the intestine.

adjuvant therapy [ad-juh-vunt]

treatment used in addition to the main treatment. It usually refers to hormone therapy, chemotherapy, radiation therapy, or immunotherapy added after surgery to increase the chances of curing the disease or keeping it in check.

adrenal gland [uh-dree-nul]

a gland at the top of each kidney (each person normally has 2). Its main function is to make hormones which control metabolism (processing food for energy), fluid balance, and blood pressure. It also makes small amounts of hormones (androgens, estrogens, and progesterone).

advance directives

A legal document that gives a person’s wishes about their health care if the person later becomes unable to make decisions for him or herself. This may include whether to start or when to stop life-sustaining treatments. Another type of advance directive lets you choose a person to make decisions for you if you become unable to do it for yourself. See also durable power of attorney for health care, living will.

advanced cancer

Cancer that has spread from where it started (the primary site) to other parts of the body. When the cancer has grown outside the body part where it started but has not yet spread to other parts of the body, it is called locally advanced cancer. If it has spread to other parts of the body, it is called metastatic cancer.

AJCC Staging System

American Joint Committee on Cancer staging system (also called the TNM system), which describes the extent of a cancer’s spread in Roman numerals from 0 through IV. See also staging.

allele [uh-LEEL]

any one of the different genes that may occupy a specific location on a given chromosome. See also chromosome, gene.

allogeneic stem cell transplant [A-loh-jeh-NAY-ik bone MAYR-oh TRANZ-plant]

Uses bone marrow or stem cells from a donor whose tissue type closely matches the patient’s to replace blood-forming cells that have been destroyed by disease or cancer treatment. This can be from a related donor or an unrelated donor. See also hematopoietic stem cell transplant, stem cells.

alopecia [al-o-PEE-shuh]

Hair loss, which can include loss of scalp hair, body hair, eyebrows, and eyelashes as well as pubic hair. This often happens with chemotherapy treatment or radiation therapy. In most cases, the hair grows back after treatment ends.

alpha blocker [al-fuh]

A drug that relaxes smooth muscle tissue. Alpha blockers are sometimes used to help men who have trouble passing urine because of benign prostatic hyperplasia (BPH) by improving the flow of urine and blood. See also benign prostatic hyperplasia.

alternative therapy

An unproven or disproven therapy that is used instead of standard (proven) medical treatment. Some examples of alternative medicines are special diets, certain supplements or herbs, high doses of vitamins, etc. The American Cancer Society recommends that patients thinking about using any alternative therapy discuss it first with a member of their cancer care team to be sure that they know all their options. Some alternative therapies are known to cause harmful or even life-threatening side effects. With others, the main danger is that the patient may lose the chance to benefit from standard treatment. See also complementary therapy.

alveoli [al-VEE-oh-lie]

Small air sacs in the lungs where oxygen and carbon dioxide are exchanged.

ambulatory [AM-byou-luh-tor-ee]

Being able to walk or walking. Ambulatory care centers work with outpatients, that is, people who are not staying overnight in a hospital. Short procedures or treatments are often done in such centers.  

Amsterdam criteria [am-STIR-dam cry-TEER-ee-uh]

A set of common characteristics in people with hereditary non-polyposis colon cancer (HNPCC). Not all people who have HNPCC meet these criteria, but people who meet the criteria may want to consider genetic testing. See also hereditary non-polyposis colon cancer.

analog [an-uh-log]

A substance that is similar, but not identical to another substance. For example, a man-made version of a naturally occurring substance. See also LHRH analogs.

anastomosis [uh-NAS-toh-MOH-sis]

A procedure in which a diseased part of a tubular body structure is removed, and the ends of healthy sections are reconnected.

androgen [AN-druh-jen]

Hormones found in males and females but with much higher levels in males; commonly called male sex hormones. The major androgen is testosterone. See also androgen deprivation therapy, hormone therapy, testosterone.

androgen ablation

see androgen blockade, androgen deprivation therapy.

androgen blockade

use of drugs to disrupt the actions of androgens or male hormones. See also androgen, androgen deprivation therapy, combined hormone therapy, hormone therapy.

androgen deprivation therapy [AN-droh-jen DEH-prih-VAY-shun]

Treatment with surgery or drugs to reduce levels of or to block the production or action of androgens (male hormones) in the body. Also called  ADT, androgen suppression therapy, androgen ablation.


a term used to describe prostate cells that are stimulated by male hormones to grow and multiply, and are suppressed by drugs that stop or disrupt the action of male hormones. Androgen-dependent cells may be normal or cancer. See also androgen-independent.


term for prostate cancer cells that no longer respond to hormone therapy; also known as hormone-refractory. See also androgen-dependent.

anecdotal report [an-neck-DOE-tul]

Individual or personal report, an incomplete description from one or more patients. It’s not the same as the results of a scientific study.

anemia [uh-NEE-mee-uh]

Low red blood cell count.

anesthesia [an-es-THEE-zhuh]

The loss of feeling or sensation as a result of medicines or substances to keep patients from feeling pain during surgery or other procedures.

  • General anesthesia causes loss of consciousness (puts you into a deep sleep so you don’t feel pain).
  • .
  •  Local or regional anesthesia numbs only a certain area, so you won’t feel pain there.

anesthesiologist [an-es-thee-zee-AHL-uh-jist]

a doctor who specializes in giving medicines or other agents that prevent or relieve pain, especially during surgery.

aneuploid [AN-you-ploid]

See ploidy.

angiogenesis [an-jee-o-JEN-uh-sis]

the formation of new blood vessels. Some cancer treatments work by blocking angiogenesis, which helps keep blood from reaching (“feeding”) the tumor. See also anti-angiogenesis agent.

angiography [an-jee-AH-gruh-fee]

a test in which a contrast dye is injected directly into a blood vessel that goes to the area that is being studied. A series of x-rays are then taken to show doctors the blood vessels around a tumor.

angiosarcoma [an-jee-o-sar-KO-muh]

a form of cancer that starts from cells that line blood vessels or lymph vessels.

anorexia [an-uh-REK-see-uh]

loss of appetite, which may be caused by either the cancer itself or treatments such as chemotherapy.

anterior [an-teer-ee-yer]

at or near the front.

anti-androgens [an-tee-AN-druh-jens or an-tie-AN-druh-jens]

drugs that block the body’s ability to use androgens (male hormones). They are taken as pills, up to 3 times a day. Anti-androgens are usually used along with orchiectomy (surgery) or LHRH analogs (medicines) to help treat prostate cancer. See also androgen, androgen deprivation therapy, luteinizing hormone-releasing hormone analogs, orchiectomy.

anti-angiogenesis agent [an-tee-an-jee-o-JEN-uh-sis or an-tie-an-jee-o-JEN-uh-sis]

a drug that stops a tumor from forming blood vessels, cutting off its blood supply. See also angiogenesis.

anti-emetic [an-tee-ih-MEH-tik or an-tie-ih-MEH-tik]

a drug that prevents or relieves nausea and vomiting.

anti-estrogen [an-tee-ES-tro-jen or an-tie-ES-tro-jen]

a substance (for example, the drug tamoxifen) that blocks the effects of estrogen on tumors. Anti-estrogens are used to treat breast cancers that depend on estrogen for growth. See also estrogen, hormone therapy, selective estrogen receptor modulator.

antibiotic [an-tee-by-AH-tick or an-tie-by-AH-tick]

drugs used to kill micro-organisms (germs) that cause disease. Antibiotics may be made naturally by living organisms or they may be created in the lab. Since some cancer treatments can reduce the body’s ability to fight infection, antibiotics may be used to treat or prevent these infections.

antibody [AN-tih-bah-dee]

a protein made by immune system cells and released into the blood. Antibodies defend the body against foreign agents, such as bacteria. These agents contain certain substances called antigens. Each antibody works against one certain antigen. See also antigen, immune system.

antigen [an-tuh-jen]

a foreign substance that causes the body’s immune system to respond by making antibodies. For example, the immune system responds to antigens that are part of bacteria and viruses to help people resist infections. Certain cancer cells have antigens that can be found by lab tests. They can help in diagnosing those cancers and in watching response to treatment. Other cancer cell antigens play a role in immune reactions that may help the body resist cancer. See also antibody, immune system.

antimetabolites [an-tee-muh-TAB-o-lites or an-tie-muh-TAB-o-lites]

substances that interfere with the body’s chemical processes, such as those that create proteins, such as deoxyribonucleic acid (DNA) and other chemicals needed for cell growth and reproduction. In treating cancer, antimetabolite drugs disrupt DNA production, which in turn prevents cell division and tumor growth. See also deoxyribonucleic acid.

antioxidants [an-tee-OX-uh-dunts or an-tie-OX-uh-dunts]

compounds that hold back chemical reactions with oxygen (oxidation). Some vitamins, such as vitamins C and E and beta-carotene are antioxidants. Antioxidants that are found in foods are thought to reduce the risk of some cancers. But taking certain antioxidants as supplements has been linked to higher cancer risk in some people.

anus [a-nus]

the end of the digestive tract, through which waste passes out of the body. See also digestive system.

APC gene

a gene that slows the growth of cells in the body. Changes in this gene can cause familial adenomatous polyposis (FAP) and Gardner syndrome. People who have a mutation (change) in this gene can develop hundreds of polyps in the colon. See also familial adenomatous polyposis, Gardner syndrome, gene, polyp.

apheresis [a-fur-REE-sis]

may also be called pheresis (fur-ree-sis). A procedure in which blood is taken out of the body, part of the blood is removed, and the rest of the blood is infused back into the body. May be called plasmapheresis if plasma is removed, leukapheresis if white blood cells are removed, or platelet pheresis when platelets are removed.

apoptosis [a-pop-TOE-sis]

programmed cell death. Apoptosis is controlled by genes that cause cells to die at certain times, for example, when DNA is damaged. This type of cell death is different from the process of cell death by decay. Some drugs used to treat cancer cause apoptosis.

areola [ah-ree-uh-luh or air-ee-o-la]

the dark area of skin that surrounds the nipple of the breast.

aromatase inhibitors

drugs that keep the adrenal glands from making estrogens. They are used to treat hormone-sensitive breast cancer in women after menopause. Examples include anastrozole (Arimidex®), letrozole (Femara®), and exemestane (Aromasin®). Aromatase inhibitors are being tested to find out if they can also be used to reduce breast cancer risk in women after menopause. See also chemoprevention, estrogen, hormone therapy, menopause.

artificial sphincter [sfink-ter]

an inflatable cuff implanted to squeeze the urethra or anus shut and help a person control their urine or stool. See also incontinence, sphincter.

ascending colon [as-send-ing ko-lun]

the first of the 4 sections of the colon. The ascending colon begins at the end of the small intestine and extends upward on the right side of the abdomen to connect with the transverse colon. See also abdomen, colon, transverse colon, descending colon, sigmoid colon.

aspiration [asp-er-A-shun]

to draw out a liquid, gas, or tissue fragments using suction. See also fine needle aspiration biopsy.

asymptomatic [a-simp-tuh-MAT-ik]

not having any symptoms of a disease. Many cancers can develop and grow without causing symptoms, especially in the early stages. Screening tests such as mammograms and colonoscopies help find these early cancers before symptoms start, when the chances for cure are usually highest. See also screening.

ataxia-telangiectasia mutation [a-tax-ee-yuh tel-an-jee-eck-TAY-zhuh]

also called ATM. An inherited mutation in a certain gene responsible for repairing damaged deoxyribonucleic acid (DNA). If this mutation is present, the carrier may have a higher risk of several types of cancer. See also deoxyribonucleic acid, gene, genetic testing, mutation.


see ataxia-telangiectasia mutation.

atypia [a-tip-ee-yuh]

not normal; atypical. Often refers to the appearance of cancerous or pre-cancerous cells. See also atypical, hyperplasia.

atypical [a-tip-uh-kul]

not usual; abnormal. See also atypia.

atypical small acinar proliferation [a-tip-uh-kul small uh-see-nar pruh-lih-fuh-RAY-shun]

also called ASAP. These are prostate cells that look like they might be cancer, but there are too few cells in the biopsy sample to be sure. With ASAP, there’s about a 40% to 50% chance of prostate cancer, so many doctors advise a repeat biopsy within a few months. See also biopsy, prostatic intraepithelial neoplasia.

autologous [aw-tahl-uh-gus]

use of the patient’s own blood or tissue in a medical procedure; for example, using a woman’s own tissue to rebuild her breast is called autologous tissue construction.

autologous stem cell transplant [aw-tahl-uh-gus]

a complex and sometimes risky treatment that may be used when cancer is advanced or has come back, or as the main treatment in some types of leukemia or lymphoma. Either bone marrow or stem cells harvested from the patient’s bloodstream is removed, cleaned, and stored. The patient is then given high doses of chemotherapy and/or radiation to kill the cancer cells. This also destroys the remaining bone marrow, making the body unable to fight infection. The saved stem cells are then given by transfusion (transplanted) to restore the patient’s immune defenses. The best place to have a transplant is at a comprehensive cancer center or other facility that has the technical skill and experience to perform it safely. Compare to allogeneic stem cell transplant. See also bone marrow, hematopoietic stem cell transplant, immune system.

axilla [ax-ill-uh]

the armpit.

axillary dissection [ax-ill-air-ee di-sek-shun]

removal of the lymph nodes in the armpit (the axillary nodes). They are looked at under a microscope to see if they contain cancer. See also lymph node, lymph node biopsy.


B lymphocytes [limf-uh-sites]

also called B cells. White blood cells that help make antibodies. See also antibody, immune system, white blood cells.

barium enema [bear-ee-um en-uh-muh]

a method sometimes used to help diagnose colorectal cancer. Barium sulfate, a chalky liquid, is used to enlarge and partly fill the colon (large intestine). When the colon is about half-full of barium, air is pushed in to cause the colon to expand further. This allows good x-ray films to be taken. This procedure may be called a double contrast barium enema. See also barium sulfate, colon, colorectal cancer.

barium sulfate [bear-ee-um sul-fate]

a substance made into a chalky liquid that is used to outline the digestive tract for x-rays. It can be taken by mouth, as part of upper gastrointestinal (GI) series, or put into the rectum as a barium enema (as part of a lower GI series). See also barium enema, gastrointestinal tract.

basal cell carcinoma [bay-sul or bay-zul sell car-sin-O-ma]

the most common type of skin cancer. It begins in the lowest layer of the epidermis (the outer layer of the skin), called the basal cell layer. It usually develops on sun-exposed areas, especially the head and neck. Basal cell cancer grows slowly and is not likely to spread to distant parts of the body.

basic science

also called pure science, provides the knowledge and background required for later research into human health problems. In cancer research, this is often lab study in fields like biochemistry, cell biology, or genetics that are not aimed at treating a specific cancer, but may be used later as part of the basis for a treatment.

behavioral research

research into what motivates people to act the way they do. The results of such research can be used to help encourage people to adopt healthy lifestyles and follow life-saving screening and treatment guidelines.

benign [be-nine]

not cancer; not malignant. Compare with malignant.

benign prostatic hyperplasia [be-nine pros-tat-tick hi-per-PLAY-zhuh]

also called BPH. Non-cancerous enlargement of the prostate. This sometimes makes it harder for a man to empty his bladder – causing trouble starting and stopping urine flow, weak flow of urine, and dribbling.

benign tumor [be-nine too-mer]

an abnormal growth that is not cancer and does not spread to other areas of the body. See also tumor.

beta carotene [bay-tuh KAIR-uh-teen]

a form of vitamin A that is found mainly in yellow and orange vegetables and fruits. It functions as an antioxidant, but high doses of beta carotene supplements in smokers may increase lung cancer risk. See also antioxidants.

Bethesda criteria [beth-ez-duh cry-teer-ree-yuh]

a set of conditions common in people with hereditary non-polyposis colon cancer (HNPCC). Most people who meet these criteria actually do not have HNPCC, but might want to consider genetic testing for it. Compare to Amsterdam criteria. See also hereditary non-polyposis colon cancer, genetic testing.

bilateral [by-lat-er-ul]

on both sides of the body; for example, bilateral breast cancer is cancer in both breasts. Compare to unilateral.

biochemical failure [by-o-KEM-ih-kull]

a term sometimes used by doctors to describe a significant rise in PSA (prostate-specific antigen) after prostate cancer treatment, which is a sign that cancer may have come back. There may be many years between a rise in PSA and being able to find the cancer by other means. See also primary therapy, prostate-specific antigen, recurrence.

biologic response modifiers [by-o-LA-jick re-spons MOD-uh-fie-urs]

substances that boost the body’s immune system to fight against cancer; for instance, the drug interferon. This type of treatment is sometimes called biologic therapy. See also immunotherapy.

biomarkers [BY-o-mar-kers]

see tumor markers.

biopsy [by-op-see]

the removal of a sample of tissue to see if cancer cells are present. There are several kinds of biopsies. In some, a very thin (fine) needle is used to take out fluid and cells from a lump. In a core biopsy, a larger needle is used to remove more tissue. See also core needle biopsy, fine needle aspiration biopsy, sextant biopsy, surgical biopsy.

biopsy gun [by-op-see]

an instrument used to take core biopsy samples, often used for prostate biopsies. See also biopsy, core needle biopsy.

bisphosphonates [bis-FAHS-fun-ates]

drugs that slow down the action of bone-eating cells called osteoclasts, which helps slow the spread of cancer in the bones. Bisphosphonate drugs are commonly used in breast cancer and multiple myeloma (a type of bone cancer). They are also approved for use in men with prostate cancer that has spread to the bones.

bladder [blad-uhr]

a hollow organ in the pelvis with flexible, muscular walls. The bladder stores urine as it is made by the kidneys. See also kidney.

blood count

a count of the number of cells in a given sample of blood.

body image

the way a person thinks about their body and how they think it looks to others.

bone marrow

the soft, spongy tissue in the hollow middle of certain bones of the body. This is where new blood cells are made. See also platelet, red blood cells, white blood cells.

bone marrow aspiration and biopsy [asp-er-A-shun and by-op-see]

a procedure in which a needle is put into the center of a bone, usually the hip or breast bone, to take out a small amount of bone marrow so that it can be looked at under a microscope. See also bone marrow.

bone marrow transplant

a treatment that replaces blood-forming stem cells that have been destroyed by high doses of chemotherapy and/or radiation therapy. The bone marrow may come from the patient (autologous) or a donor (allogeneic). Bone marrow transplants (BMTs) were the first way stem cells in the bone marrow were replaced. See also allogeneic stem cell transplant, autologous stem cell transplant, umbilical cord blood transplant, hematopoietic stem cell transplant, stem cells.

bone scan

an imaging test that gives important information about the bones, including the location of cancer that may have spread to the bones. It uses a small amount of radioactive contrast material (radioisotope) which is given by vein. This material settles in areas of the bone to which the cancer may have spread. The radioactive substance can be seen in pictures as it collects in the problem areas (“hot spots”). See also imaging studies, radioisotope.

bone survey

also called a skeletal survey. An x-ray of all the bones of the body; it may be done when looking for cancer that has spread to the bones.


the intestines, from the end of the stomach (pylorus) to the anus. The small bowel is the part of the intestine that goes from the bottom of the stomach to the large bowel. The large bowel goes from there to the anus, and is also called the colon. See also anus, colon, gastrointestinal tract, intestines.


see benign prostatic hyperplasia.

brachytherapy [brake-ee-THER-uh-pee]

internal radiation treatment given by putting radioactive seeds or pellets right into the tumor or close to it. Also called interstitial radiation therapy or seed implantation. Can be used along with external beam radiation therapy. See also high-dose rate brachytherapy, permanent (low-dose rate or LDR) brachytherapy, external beam radiation therapy, ionizing radiation.


enclosed in the cranium (the bones of the head) and connected to the spinal cord, the brain is the main center for regulating and coordinating body activities. It is the seat of thought, feeling, memory, speech, vision, hearing, movement, and much more. Different parts of the brain control different different functions in the body. See also spinal cord.

brain scan

an imaging method used to find anything that isn’t normal in the brain, including brain cancer and cancer that has spread to the brain from other places in the body. This scan can be done in an outpatient clinic. It is painless, except for the needle stick when a radioactive substance (radioisotope) is put into a vein. The radioactive substance can be seen in pictures as it collects in abnormal areas. See also outpatient, radioisotope.


a gene which, when damaged (mutated), puts a person at higher risk of developing breast, ovarian, prostate, and other types of cancer, compared to people who do not have the mutation. See also gene, mutation.


a gene which, when damaged (mutated), puts a person at higher risk of developing breast, ovarian, prostate, and other types of cancer when compared to people who do not have the mutation. See also gene, mutation.


a tool used to help health professionals estimate a woman’s breast cancer risk. It estimates breast cancer risk based on certain risk factors.

breast augmentation

surgery to increase the size of the breast. See also breast implant, mammoplasty.

breast cancer

cancer that starts in the breast. The most common types of breast cancer are ductal carcinoma in situ, invasive ductal carcinoma, invasive lobular carcinoma, medullary carcinoma, and Paget disease of the nipple (see definitions under these headings). Lobular carcinoma in situ is sometimes listed as a non-invasive type of cancer, even though it is not a true cancer.

breast conservation therapy or breast-conserving therapy

surgery to remove a breast cancer and a small margin of normal tissue around the cancer without removing any other part of the breast. The lymph nodes under the arm may be removed, and radiation therapy is often given after the surgery. This method is also called lumpectomy, segmental excision, limited breast surgery, or tylectomy.

breast implant

a sac used to increase breast size or restore the shape of a breast after mastectomy (surgical removal of the breast). The sac is filled with silicone gel (a synthetic material) or sterile saltwater (saline). See also mastectomy, prosthesis.

breast reconstruction

surgery that rebuilds the breast after mastectomy (surgical removal of the breast). A breast implant or the woman’s own tissue may be used. If desired, the nipple and areola might also be re-created. Reconstruction can be done at the time of mastectomy or any time later. See also mastectomy.

breast self-exam

also called BSE. A way to check your own breasts for lumps or suspicious changes. Women over age 20 might choose to do BSE, usually at a time other than the days before, during, or right after their menstrual periods. The goal with BSE is to know what your breast tissue feels and looks like and to be able to report any breast changes to a doctor or nurse right away.

breast specialist

a health care professional who has a dedicated interest in breast health. While he or she may have specialized knowledge in this area, medical licensing boards do not certify a specialty in breast care.

bronchi [brong-ki]

the 2 main air passages in the lungs leading from the windpipe (trachea). The bronchi provide a passage for air to move in and out of the lungs. See also bronchiole, trachea.

bronchiole [brong-key-ol]

one of the smaller subdivisions or branches of the bronchi. See also bronchi.

bronchoscopy [brong-kah-skuh-pee]

looking at the bronchi using a thin, flexible, lighted tube that goes down the throat. This instrument is called a bronchoscope. See also bronchi.


CA 19-9

a tumor marker sometimes produced by colorectal, stomach, bile duct, and pancreatic cancers. It may also be produced in non-cancer conditions. See also tumor markers.


combined androgen blockade. See combination hormone therapy.

cachexia [ka-kek-see-uh]

a profound state of general poor health and malnutrition (poor food intake and/or poor food absorption).

calcifications [kals-if-ik-A-shuns]

tiny calcium deposits within the breast, seen alone or in clusters. They are often found on a mammogram. Very small deposits may be called microcalcifications. They are a sign of changes within the breast that may need to be followed by more mammograms, or by a biopsy. See also biopsy, mammogram.


a group of diseases which cause cells in the body to change and grow out of control. Most types of cancer cells form a lump or mass called a tumor. (Not all tumors are cancer. A tumor that is not cancer is called benign, while a cancerous tumor is called malignant.) A cancerous tumor can invade and destroy healthy tissue. Cells from the cancer can break away and travel to other parts of the body. There they can continue to grow. This spreading process is called metastasis. When cancer spreads, it is still named after the part of the body where it started. For example, if colon cancer spreads to the liver, it is still colon cancer, not liver cancer.

Benign tumors do not grow and spread the way cancer does. They are usually not a threat to life. Note that some types of cancer, such as blood cancers, do not form tumors. They can still threaten life by crowding out normal cells. See also benign, malignant, metastasis, tumor.

cancer care team

the group of health care professionals who work together to find, treat, and care for people with cancer. The cancer care team may include any or all of the specialists listed. Whether the team is linked formally or informally, there is usually one person who takes the job of coordinating the team. See also medical oncologist, radiation oncologist, pathologist, oncology clinical nurse specialist, oncology social worker, neurosurgeon, surgeon, gynecologist, gynecologic oncologist, urologist.

cancer cell

a cell that divides and reproduces abnormally and can spread throughout the body, crowding out normal cells and tissue. Cancer cells develop because of damage to deoxyribonucleic acid (DNA). See also cancer, deoxyribonucleic acid, mutation.

cancer screening tests

see screening.

cancer susceptibility genes

genes (the basic unit of heredity) inherited from one’s parents that greatly increase the risk of a person’s developing cancer. About 5% to 15% of all cancers are caused by these genes. See also gene.

cancer vaccine

a vaccine used to help the body fight cancer cells. So far, a vaccine has been approved to help treat cancer (not prevent it). It is made for each patient using pieces of their tumor and works by causing their immune system to recognize and attack the cancer cells. There are also researchers trying to develop vaccines to prevent certain types of cancer, although none have yet been approved for use. Another type of vaccine that is already in use reduces cancer risk indirectly, by helping the body fight cancer-causing viruses such as the human papilloma virus (HPV) and the hepatitis B virus. See also human papilloma virus.

cancer-related fatigue

an unusual and ongoing tiredness that can occur with cancer or cancer treatments. It can be overwhelming, last a long time, and interfere with everyday life. Rest does not always relieve it.


a narrow tube-like device. Different kinds may be used to hold open tissues during laparoscopy, or to give IV medicines and fluids. See also intravenous (IV), laparoscopy.

capsule formation

scar tissue that may form around an implant as the body reacts to the foreign object. See also adhesions.

carcinoembryonic antigen [car-sin-o-em-bre-ON-ic an-tuh-jin]

a substance normally found in certain fetal tissues. If found in an adult, it may suggest that a cancer, especially one starting in the digestive system, may be present. Tests for this substance may help doctors find out if a colorectal cancer has come back after treatment. The test is not helpful for screening for colorectal cancer because of the large number of false positives and false negatives. See also digestive system, false negative, false positive, screening, tumor marker, colorectal cancer.

carcinogen [car-sin-o-jin]

any substance that causes cancer or helps cancer grow. For example, tobacco smoke contains many carcinogens that greatly increase the risk of lung cancer, and many other types of cancer.

carcinoid syndrome [car-sin-oyd sin-drom]

A group of symptoms produced by cancer cells that release large amounts of hormones, which cause facial flushing, wheezing, diarrhea, a fast heartbeat, and other symptoms. See also carcinoid tumors, hormone.

carcinoid tumors [car-sin-oyd]

also called carcinoids. Tumors that develop from neuroendocrine (nerve and endocrine) cells, usually in the digestive tract or lung. The cancer cells from these tumors release certain hormones into the bloodstream. In about 10% of people, the hormone levels get high enough to cause facial flushing, wheezing, diarrhea, a fast heartbeat, and other symptoms. See also carcinoid syndrome, endocrine glands, hormone.

carcinoma [car-sin-O-ma]

a cancer that begins in the lining layer (epithelial cells) of organs. At least 80% of all cancers are carcinomas.

carcinoma in situ [car-sin-O-ma in sy-too]

an early stage of cancer in which the tumor is confined to the organ where it first developed. The disease has not invaded other parts of the organ or spread to distant parts of the body. Most in situ carcinomas are highly curable. See also carcinoma.

case manager

the member of a cancer care team, usually a nurse or oncology nurse specialist, who coordinates the patient’s care throughout diagnosis, treatment, and recovery. The case manager acts as a guide through the complex system of health care by getting responses to questions, managing crises, and connecting the patient and family to people or groups that can offer needed help. See also cancer care team.

castration [cass-tray-shun]

surgery to remove the testicles; the medical term is orchiectomy. See also androgen deprivation therapy, testicles.

catheter [cath-it-ur]

a thin, flexible tube through which fluids enter or leave the body; for example, a tube to drain urine is a Foley catheter.

causal association or causal link [kaw-zul]

a relationship in which one factor is thought to be responsible for or cause an outcome; for instance, smoking has a causal link to lung cancer.


a gene that makes a protein called epithelial cadherin. A mutation in this gene can cause hereditary diffuse gastric cancer (a rare type of stomach cancer) to develop at an early age. Women who inherit changes in this gene also have a higher risk of lobular breast cancer. See also inherited disease, lobular carcinoma in situ, mutation.


see carcinoembryonic antigen.

cecum [see-kum]

a blind pouch near where the small intestine empties into the large intestine, at the start of the colon. See also colon, gastrointestinal tract.


the basic building unit of all living things. Cells replace themselves by splitting and forming new cells (this process is called mitosis). The processes that control the formation of new cells and the death of old cells are disrupted in cancer. See also cancer.

cell cycle

the series of steps that a cell must go through to divide; some chemotherapy drugs work by interfering with the cell cycle. See also chemotherapy.

centigray [cent-uh-gray]

a unit for measuring radiation transfer. See also radiation dose.

centimeter [SIN-tuh-me-ter]

also written as cm. Metric measure of length, 1/100 of a meter. It takes about 2½ cm to equal 1 inch. See also meter, millimeter.

cerebrospinal fluid [suh-REE-bro-spy-nuhl]

also called CSF. A special clear liquid that surrounds and cushions the brain and spinal cord. See also brain, spinal cord.

cervix [ser-vix]

the lower part, or neck, of the womb (uterus), which connects the uterus to the vagina. See also uterus, vagina.


See Gray under radiation dose.


a gene that if damaged or mutated, can increase the risk of breast and other types of cancer. This damaged gene can be inherited. See also gene, inherited disease, mutation.

chemical castration [KEM-ih-kul cast-ray-shun]

the use of hormone therapy drugs to achieve very low levels of testosterone without surgical removal of the testicles. See also androgen deprivation therapy, castration, testicles.

chemo brain [key-mo brain]

also written chemobrain or chemo-brain; sometimes called chemo fog. The mental cloudiness people with cancer sometimes notice before, during, and after chemotherapy.. Despite the name, researchers are finding other factors that also seem to be linked to this problem.

chemoprevention [key-mo-pre-VEN-shun]

prevention or reversal of disease using drugs, chemicals, or other substances. This idea is not ready for widespread use in cancer care, but it is a promising area of study. For instance, the drugs tamoxifen and raloxifene are approved to help reduce breast cancer risk among women at very high risk of the disease.

chemotherapy [key-mo-THER-uh-pee]

treatment with drugs that kill cancer cells. Chemotherapy is often used, either alone or with surgery and/or radiation, to treat cancer that has spread or come back (recurred), or when there is a strong chance that it could come back. Often called chemo.

chromogenic in situ hybridization or CISH [kro-mo-JEN-ick in sy-too hi-brid-ih-ZA-shun]

a lab test that uses small deoxyribonucleic acid (DNA) probes to count the number of HER2 genes in breast cancer cells. See also deoxyribonucleic acid, gene, human epidermal growth factor receptor 2.

chromosome [KROM-uh-som]

strand of deoxyribonucleic acid (DNA) inside a cell that carries genes, the basic units of heredity. Humans have 23 pairs of chromosomes, one member of each pair from the mother, the other from the father. Each chromosome can contain hundreds or thousands of individual genes. See also deoxyribonucleic acid, gene.

chronic inflammatory bowel disease

see inflammatory bowel disease.

chronic obstructive pulmonary disease or COPD [kron-ick ob-struck-tiv PULL-muh-nerr-ee]

lung disease such as emphysema or chronic bronchitis, that harms the lungs and makes it harder to breathe. More common in smokers.

chyme [kime]

the thick, nearly liquid mixture of partly digested food and digestive juices found in the stomach and small intestine.

Claus model

a tool used to help health professionals estimate a woman’s breast cancer risk. It gives an estimate of breast cancer risk based on certain risk factors.

clavicle [klav-ih-kuhl]

the collarbone. One sits above each breast and is joined to the breastbone (sternum). Lymph nodes are above and below this bone. See also lymph node, infraclavicular, supraclavicular.

clinical breast examination [CBE]

Often shortened to CBE. Examination of the breasts done by a health professional such as a doctor or nurse to check for lumps or other changes. Clinical breast exam is no longer recommended for breast cancer screening.

clinical stage

see staging.

clinical trials

research studies that use human volunteers to test new drugs or other treatments to compare current, standard treatments with others that may be better. They may also test new ways to diagnose or prevent a disease. Before a new treatment or test is used on people, it is studied in the lab. If lab studies suggest it will work, the next step is to test it in patients. There are 3 main questions the researchers want to answer.

  • Does this treatment or test work better than what we use now?
  • What side effects does it cause?
  • Do the benefits outweigh the risks?

colectomy [kuh-lek-tuh-me]

surgery that removes all (total colectomy) or part (partial colectomy or hemicolectomy) of the colon. See also colon, bowel, colostomy, segmental resection, anastomosis.

colitis [kuh-lie-tis]

a general term for inflammation of the large intestine (colon). Colitis can be intermittent (it comes and goes) or chronic (long-lasting, as in ulcerative colitis). See also colon, inflammatory bowel disease.

colo-anal anastomosis [ko-lo-A-nuhl uh-nas-tuh-MO-sis]

surgery for rectal cancer in which the rectum is removed and the colon is attached to the anus. Sometimes a small pouch is made to take the place of the rectum, by doubling back a short segment of colon (colonic J-pouch) or enlarging a segment (coloplasty). A temporary colostomy is needed while the pouch heals. See also anus, colon, colostomy, low anterior resection, rectum.

colon [ko-lun]

the major part of the large intestine. The colon is a muscular tube about 5 feet long. It is divided into 4 sections, starting with the ascending, transverse, descending, and ending with the sigmoid colon. It continues the process of absorbing water and mineral nutrients from food that was started in the small intestine. The cecum and the rectum mark the beginning and end of the colon, though they are not actually part of it. See also rectum, cecum.

colon wall

several layers of muscle and mucous membrane make up the colon wall. Starting with the inside layer and moving outward, they are called the mucosa, muscularis mucosae, submucosa, muscularis propria, subserosa, and serosa. Cancers that start inside the colon and grow outward may grow through all these layers and invade other organs. These same layers are present in most of the intestines (digestive tube).

colonoscope [ko-LAHN-uh-scope]

a thin, flexible, hollow lighted tube about the thickness of a finger. It is put in through the rectum and moved up into the colon. The colonoscope is connected to a video camera and monitor screen so the doctor can look closely at the inside of the entire colon. Compare to sigmoidoscope. See also colon, colonoscopy, rectum.

colonoscopy [ko-lun-AH-skuh-pee]

a procedure that lets a doctor see inside the large intestine, including the colon, to find polyps or cancer. See also colon, colorectal cancer screening, colonoscopy preparation.

colonoscopy preparation [ko-lun-AH-skuh-pee]

also called colonoscopy prep. The use of a liquid diet along with laxatives and enemas to clean out the entire colon before the colonoscopy or virtual colonoscopy is done. This preparation is usually started 1 or 2 days before the colonoscopy. See also colon, colonoscopy, virtual colonoscopy.

colony-stimulating factors [CSF]

types of growth factors that promote growth and division of blood-producing cells in the bone marrow. CSFs are naturally produced in the body. Extra amounts may be given to reduce or prevent certain side effects of chemotherapy that may be caused by not having enough blood cells. They may also be given before harvesting stem cells from a donor for peripheral blood stem cell transplant. See also bone marrow, chemotherapy, hematopoietic stem cell transplant, stem cells.

color Doppler ultrasound

a type of ultrasound that uses a computer to convert sounds into colors to represent blood flow within an organ. It may be used to help find cancers in the prostate, since tumors often have more blood flow than normal tissue. See also prostate, transrectal ultrasound, ultrasound.

colorectal cancer [ko-lo-REK-tuhl]

colon or rectal cancer. Since colon cancer and rectal cancer have many features in common they are often referred to together as colorectal cancer. See also colon, rectum.

colorectal cancer screening [ko-lo-REK-tuhl]

testing done to find abnormalities early, before signs and symptoms start. This allows cancer to be found earlier, when it is most curable. Some types of screening allow doctors to find and remove polyps, which can even prevent cancer from developing. See also screening, barium enema, colonoscopy, fecal occult blood test, fecal immunochemical test, polyp, sigmoidoscopy.

colostomy [kuh-lahs-tuh-me]

an operation in which the end of the colon is attached to an opening created in the belly (abdominal wall) to get rid of body waste (stool). A colostomy is sometimes needed after surgery for cancer of the rectum. People with colon cancer sometimes have a temporary colostomy but they rarely need a permanent one. See also colon, rectum.

colposcopy [kol-pa-skuh-pee]

a close examination of the inside of the vagina and the cervix (bottom of the womb) using a colposcope, a lighted magnifying device. See also cervix, vagina.

combination hormone therapy

use of multiple ways to affect the body’s hormones. For example, complete blockage of androgen (male hormone) production that may include castration or use of LHRH analogs, plus the use of anti-androgens can be used to treat prostate cancer. This is also called combined androgen blockade (CAB), total hormonal ablation, total androgen blockade, or total androgen ablation. See also androgen, androgen deprivation therapy, castration, hormone therapy, luteinizing hormone-releasing hormone analogs.

combined androgen blockade [CAB]

see combination hormone therapy.

combined modality therapy [mo-dal-ih-tee]

2 or more types of treatment used alternately or together to get the best results. For example, surgery for cancer is often followed by chemotherapy to kill any cancer cells that may have spread from the original site. See also adjuvant therapy, neoadjuvant therapy, chemotherapy.

comedocarcinoma [kom-id-o-car-sin-NO-muh]

ductal carcinoma in situ that has dead or dying cancer cells in its center. See also ductal carcinoma in situ.

complementary therapy

a non-standard treatment (often self-prescribed) used along with standard medical treatment. Some complementary therapies may help relieve certain symptoms of cancer, relieve side effects of standard cancer therapy, or improve a patient’s sense of well-being. These can include herbs, meditation, massage or touch, and many other types of treatments. The ACS recommends that patients thinking about using any alternative or complementary therapy discuss it first with a member of their health care team, since many of these treatments are unproven and some can be harmful. Compare with alternative therapy.

complexed PSA

the amount of PSA (prostate-specific antigen) in the blood that is bound to other proteins (the portion of PSA that is not “free”). This test is done instead of checking the total and free PSA, and it could give the same amount of information as the other two done separately. Studies are now under way to see if this test provides the same level of accuracy. See also percent-free PSA, prostate-specific antigen.

computed tomography scan [toe-mahg-ruh-fee]

also called a CT scan or CAT scan. An imaging test in which many x-rays are taken from different angles of a part of the body. These images are combined by a computer to make cross-sectional pictures of internal organs. Except for the injection of a dye (needed in some but not all cases), this is a painless procedure that can be done in an outpatient clinic. See also outpatient, imaging studies, ionizing radiation.

computer-aided detection or diagnosis [CAD]

a process in which a radiologist uses a computer program to help interpret a mammogram or other imaging test. See also imaging studies, mammogram.

concurrent treatment

treatment or therapy that is given at the same time as another treatment.

conditioning treatment

chemotherapy and/or radiation therapy used to destroy the bone marrow or reduce its function in order to prepare for a hematopoietic stem cell transplant. See also hematopoietic stem cell transplant, myeloablative treatment, reduced-intensity conditioning.

conformal proton beam therapy

a technique for giving radiation therapy that uses proton beams rather than standard radiation. (Protons are parts of atoms.) Unlike standard radiation beams, which release energy both before and after hitting the target, proton beams cause less damage to tissues they pass through. They release their energy after traveling a certain distance. Proton beam therapy is still fairly new and not offered in all treatment centers. It has not been directly compared to standard radiation methods, but the hope is that it may be able to deliver more radiation to the cancer with less damage to normal tissues. See also conformal radiation therapy, external beam radiation therapy, ionizing radiation.

conformal radiation therapy

a newer type of radiation treatment that uses a special computer which helps shape the beams of radiation to the shape of the tumor. It also delivers the beams from several different directions rather than all going in from one angle. This cuts down the amount of exposure that any one section of healthy tissue gets by spreading out the entry points. See also external beam radiation therapy, ionizing radiation, photon beam radiation therapy.

control group

in research or clinical trials, the group that does not get the treatment being tested. In cancer research, this group most often gets standard treatment (which has already been tested and is in general use). If no standard treatment exists, the control group may get a placebo or sham treatment. Sometimes called the comparison group. See also clinical trials.

conventional therapy or treatment

see standard therapy.


see chronic obstructive pulmonary disease.

cord blood transplant

see umbilical cord blood transplant.

core needle biopsy

a procedure used to get tissue samples. The needles remove a small cylinder of tissue, about 1/16 inch across. A pathologist looks at these samples under a microscope to see if cancer is present. See also biopsy, biopsy gun, pathologist.

corpora cavernosa [kor-puh-ruh kav-er-NO-suh]

two chambers that run along on each side of the length of the penis, which fill with blood during an erection. A smaller third chamber called the corpus spongiosum also fills during a normal erection. See also corpus spongiosum.

corpus spongiosum [kor-pus spun-jee-OH-sum]

the chamber that runs along the length of the penis (around the urethra) that fills with blood during an erection. The 2 larger chambers on each side of the penis called the corpora cavernosa also fill during a normal erection. See also corpora cavernosa, urethra.

corticosteroid [kor-tih-ko-STEER-oyd]

any of a number of steroid substances that come from the cortex (outer layer) of the adrenal glands. They are sometimes used as cancer treatments or to reduce nausea. They are also used to relieve bone pain in patients with cancer in the bones.

cranium [cray-nee-um]

the part of the skull bones that enclose and protect the brain, and support the structures of the face. See also brain.

Crohn’s disease or Crohn’s colitis [kronz]

a type of chronic inflammatory bowel disease. In this condition, the small bowel or, less often, the colon is inflamed over a long period of time. This increases a person’s risk of developing colon cancer. Colorectal cancer screening should be started earlier and done more often in people with Crohn’s. See also colon, colorectal cancer screening, inflammatory bowel disease, small intestine.

cryoablation [cry-o-ah-BLAY-shun]

use of extreme cold to freeze and kill cancer cells.

cryosurgery [cry-o-SUR-juh-ree]

see cryoablation.

CT colonography

see virtual colonoscopy.

CT scan or CAT scan

see computed tomography.

CT-guided needle biopsy

a procedure that uses special x-rays to show a tumor while the doctor advances a biopsy needle toward it. The images are repeated until the doctor is sure the needle is in the tumor or mass. A biopsy is then taken from it to be looked at under the microscope. See also biopsy.

curative treatment [kur-uh-tiv]

treatment aimed at producing a cure. Compare with palliative treatment.

cyst [sist]

a fluid-filled mass that is usually not cancer. The fluid can be removed to be tested. See also needle aspiration.

cystoscope [SIS-tuh-skop]

a thin, flexible tube with a lens and a light. It is put into the bladder through the urethra, allowing the doctor to see the insides of these organs. See also bladder, cystoscopy, urethra.

cystoscopy [sis-tah-skuh-pee]

a procedure that looks at the inside of the urethra and bladder with a thin, flexible, lighted tube called a cystoscope. See also bladder, cystoscope, urethra.

cytogenetics [sy-toe-juh-NET-icks]

tests that look for abnormal changes (mutations) in whole chromosomes. Also called chromosome analysis, it is one of many different types of genetic tests available today. It is often done on bone marrow samples in patients with leukemia. See also bone marrow, chromosome, mutation, genetic testing.

cytokine [sy-toe-kine]

A substance that is made by cells of the body’s immune system that can affect the immune response. Cytokines can also be made in the lab and given to people to help the body’s immune responses against cancer. See also immune system.

cytology [sy-tahl-uh-jee]

the branch of science that deals with the structure and function of cells. Also refers to tests to diagnose cancer and other diseases by looking at cells under the microscope. See also cell.

cytometry [sy-tahm-uh-tree]

the counting and measuring of cells using a machine called a flow cytometer. See also cells.

cytotoxic [sy-tuh-TOK-sick]

toxic to cells; cell-killing. See also cells.


D & C

see dilation and curettage.

debulk [de-bulk]

to surgically reduce the volume or amount of cancer, usually by removing all that can be safely taken out.

deoxyribonucleic acid [dee-ok-see-ri-bo-noo-KLEE-ick]

also called DNA. The genetic “blueprint” found in the nucleus (center) of each cell. DNA holds genetic information on cell growth, division, and function. See also mutation.

depot injection [dee-poe or dep-oh]

an injection (shot) of a drug in a form that allows it to enter the bloodstream slowly over time. These drugs can often be given every month or even once every few months.

dermatologist [der-muh-TAHL-uh-jist]

a doctor who specializes in skin diseases.


see diethylstilbestrol.

descending colon [de-send-ing ko-lun]

the third section of the colon. This section starts at the end of the transverse (crosswise) section and continues downward on the left side of the abdomen (belly) before connecting with the sigmoid colon. See also colon, ascending colon, transverse colon, sigmoid colon.


finding disease. Early detection usually means that the disease is found at an early stage, when it is easier to treat, before it has grown large or spread. Certain tests are used before a person has any symptoms to try to find cancer early. This can help because many forms of cancer can reach an advanced stage without causing symptoms. See also screening.


see dihydrotestosterone.

diagnosis [die-ug-NO-sis]

identifying a disease by its signs or symptoms, and by using imaging tests, lab tests, or biopsy. For most types of cancer, the earlier a diagnosis of cancer is made, the better the chance for long-term survival. See also biopsy, imaging studies, sign, symptom.

diaphragm [DIE-uh-fram]

a dome-shaped muscle that separates the chest from the abdomen (belly). The diaphragm moves down to pull air into the lungs, and up to push it out.

dietary supplement

a product, such as a vitamin, mineral, or herb, intended to improve health but not to diagnose, treat, cure, or prevent disease. Because dietary supplements are not legally considered drugs, their manufacturers can sell them without having to prove they are safe or effective.

diethylstilbestrol [die-ETH-ul-still-bes-trahl]

a man-made form of estrogen which can increase risk of certain cancers for anyone who was exposed to it during gestation (as an embryo or fetus if the mother took it during pregnancy). Women who took this drug while pregnant may be at a slightly higher risk of breast cancer. It is no longer available in the United States. See also estrogen.

dietitian or registered dietitian [die-uh-TISH-un]

an expert in the area of food and diet. A registered dietitian (RD) has at least a bachelor’s degree and has passed a national competency exam. The term nutritionist is also used, but there are no licensing or educational requirements for using this title in most states.

differentiation [dif-uhr-en-she-A-shun]

the normal process through which cells mature so they can do the jobs they were meant to do. Cancer cells are less differentiated than normal cells. Pathologists (doctors who diagnose diseases by looking at or testing samples in the lab) grade the cells to evaluate and report the degree of a cancer’s differentiation.

digestive system

the collection of organs (some of which make up the gastrointestinal tract, or GI tract) that processes food for energy and rids the body of solid waste matter.

digital mammography

a way of storing an x-ray picture of the breast as a computer image rather than on the usual x-ray film. Digital mammography can be combined with computer-assisted detection or diagnosis (CAD), a process in which the radiologist uses the computer to help interpret or “read” the mammogram. See also radiologist, mammogram.

digital rectal exam [DRE]

an exam in which the doctor puts a lubricated, gloved finger into the rectum to feel for anything that isn’t normal. This simple test, which is generally not painful, can find many rectal cancers and some prostate cancers. See also prostate, rectum.

dihydrotestosterone [die-hi-dro-tes-TOSS-ter-own]

a powerful form of male hormone produced by the action of 5-alpha reductase (a prostate enzyme) on testosterone. See also 5-alpha reductase, testosterone.

dilation and curettage [die-lay-shun and cure-uh-TAZH]

also called D & C. A procedure in which the cervix is opened slightly so that tissue from the lining of the uterus (womb) can be removed. This is often used to get tissue for biopsy. In some cases, all of the contents of the uterus are removed. See also biopsy, cervix, uterus.


a pucker or indentation of the skin. On the breast, it might be a sign of cancer.

disease-free survival rate

the percentage of people with a certain cancer who are still living and have no evidence of cancer at a certain period of time (usually 5 years) after treatment. Compare to five-year survival rate, five-year relative survival rate.

dissection [di-sek-shun]

surgery to divide, separate, or remove tissues. See also axillary dissection.

distant cancer

cancer that has spread far from its original location or primary site to distant organs or lymph nodes. Sometimes called distant metastases. Compare to localized cancer. See also primary site, metastasis.

diverticulitis [die-ver-tick-you-LIE-tis]

small pouches that form at weak points in the colon wall, which can cause slight bleeding and positive results on fecal occult blood tests (FOBTs) and fecal immunochemical tests (FITs). See also colon, fecal occult blood tests, fecal immunochemical tests.


see deoxyribonucleic acid.

DNA repair

the process of correcting the genetic mistakes that are made each time a cell divides. If the repair process does not go right, it can increase the chances of a person having some forms of cancer. See also deoxyribonucleic acid, mutation.

dopamine [dope-uh-meen]

a chemical messenger in the brain and nervous system. Dopamine is thought to control balance, movement, and other body functions. It also affects mood, memory, and attention and is linked to feelings of pleasure.

dose-dense chemotherapy

giving the usual doses of chemo closer together (usually every 2 weeks rather than every 3-weeks). This aggressive schedule requires drugs called growth factors to be given to prevent low blood counts. This approach can lead to more side effects and be harder to take, so it is only used to treat patients who have a higher chance of the cancer coming back after treatment. See also growth factors

dosimetrist [doe-sim-uh-trist]

a person who plans and calculates the correct radiation dose for each patient’s cancer treatment. See also radiation.

double contrast barium enema

test used to help diagnose colorectal cancer. Barium sulfate, a chalky substance, is put in through the rectum to partly fill and open up the colon. When the colon is about half-full of barium, air is put in to expand the colon. Abnormal changes in the colon can then show up on x-ray films. Also called DCBE and barium enema with air contrast. See also barium enema, colon, colorectal cancer screening, rectum.

doubling time

for cancer in general, the time it takes for a cell to divide or for a cancer to double itself in size. Cancers vary in doubling time from 8 to 600 days, averaging 100 to 120 days. Thus, a cancer may be present for many years before it can be found. Compare to PSA doubling time.


see digital rectal exam.

drug resistance

the ability of cancer cells to resist the effects of the chemotherapy drugs used to treat cancer.


a hollow passage through which fluids such as bile or saliva to leave the glands where they are made. In the breast, milk passes from the lobule (which makes the milk) through ducts to the nipple. See also glands.

duct ectasia [ek-tay-zhuh]

widening of the ducts of the breast, often related to breast inflammation called periductal mastitis. Duct ectasia is benign (not cancer). Symptoms of this condition are a nipple discharge, swelling, retraction of the nipple, or a lump that can be felt.

ductal carcinoma in situ [duck-tul car-sin-O-ma in sy-too]

also called DCIS and intraductal carcinoma. Cancer cells that start in the milk passages (ducts) but have not grown through the duct walls into the nearby tissue. This is a highly curable form of breast cancer that is treated with surgery, or surgery plus radiation therapy.

ductogram [DUCK-tuh-gram]

a test in which a fine plastic tube is put into the nipple of the breast and a contrast dye is injected to outline the shape of the duct. X-rays are then taken to see if there is a mass. Also called a galactogram. See also nipple, duct.

Dukes staging system

one of the staging systems for colorectal cancer, which uses the letters A through C. See also staging, colorectal cancer.

durable power of attorney for health care

a legal document that allows you to appoint a person to make medical decisions for you if you become unable to do so for yourself in the future. This is a type of advanced directive. Compare to living will. See also advance directives.

dysphagia [dis-fay-zhe-uh]

trouble swallowing or eating.

dysplasia [dis-play-zhuh]

abnormal changes of groups of cells that may lead to cancer.


early detection

see detection.

edema [uh-deem-uh]

build-up of fluid in the tissues, causing swelling. See also lymphedema.

efficacy [EF-ih-kuh-see]

effectiveness. The ability of a treatment to produce the desired result.

ejaculate [ih-JACK-you-late]

to release semen during male orgasm. See also retrograde ejaculation, semen.

electrofulguration [e-lek-tro-ful-ger-A-shun]

also known as electrocautery. A type of treatment that destroys cancer cells by burning with an electrical current.

embolization [em-buh-li-ZAY-shun]

a type of treatment that reduces the blood supply to the cancer by injecting materials to plug up the artery that supplies blood to the tumor.

emesis [em-eh-sis]

vomit or vomiting.

endocavitary radiation therapy [end-oh-KAV-uh-terr-ee]

radiation for cancer delivered from a handheld device that is placed inside a body opening. It may be given alone or with external beam radiation therapy. See also external beam radiation therapy, radiation therapy.

endocrine glands [en-duh-krin]

glands that release hormones into the bloodstream. The ovaries, testicles, thyroid, and adrenals are all examples of endocrine glands. See also adrenal gland, glands, hormones, ovary, testicles, thyroid.

endocrine therapy [en-duh-krin]

manipulation of hormones to treat a disease or condition. See also hormone therapy.

endocrinologist [en-duh-kruh-NAHL-uh-jist]

a doctor who specializes in diseases related to the glands of the endocrine system, such as the thyroid, pancreas, and adrenal glands. See also adrenal gland, endocrine glands, pancreas, thyroid.

endometrium [en-doe-ME-tree-um]

the lining of the womb (uterus). See also uterus.

endorectal coil [en-doe-REK-tuhl]

a probe that is placed and left in the rectum during an MRI, which helps get a more accurate picture of the prostate area. See also magnetic resonance imaging (MRI), prostate, rectum.

endorectal ultrasound [en-doe-REK-tuhl]

a test that uses sound waves from a probe placed in the rectum; also called transrectal ultrasound. It can be used to see how far through the wall a rectal cancer may have spread, and if it has spread to nearby organs or lymph nodes. See also lymph node, rectum, ultrasound.

endoscopy [en-dahs-kuh-pee]

inspection of the inner linings of hollow body organs or cavities using a thin, flexible, lighted tube called an endoscope.

enterostomal therapist [en-ter-oh-STO-mal ther-uh-pist]

a health professional, often a nurse, who teaches people how to care for ostomies (surgically created openings such as a colostomy) and other wounds. See also stoma.

enucleation [ee-noo-klee-AY-shun]

surgical removal of something without cutting into it. Sometimes used to describe removal of a whole tumor; also may describe removing the whole eyeball while leaving eye muscles and other contents of the eye socket.

enzyme [en-zime]

proteins that start, help, or speed up the rate of chemical reactions in living cells.

epidemiology [ep-ih-deem-ee-AHL-uh-jee]

the study of diseases in populations (large groups of people from the general population who share a common factor such as age, sex, or health condition) by collecting and analyzing statistical data. In the field of cancer, epidemiologists look at how many people have cancer; who gets certain types of cancer; and what factors (such as environment, job hazards, family patterns, and personal habits, like smoking and diet) are linked to developing cancer.

epidermal growth factor [ep-ih-DERM-uhl]

hormone-like substances linked to certain types of cancer that are known to make cells grow. Some cancer cells grow faster because they contain more growth factor receptors than normal cells. See also hormone.

epididymis [ep-ih-DID-uh-mus]

tiny tubes inside the scrotum that sit coiled on top of and behind each testicle. Sperm travel through these tubes after forming and are stored there until they mature; the tubes lead into the vas deferens. See also scrotum, sperm, testicles, vas deferens.

epidural anesthesia [ep-ih-DUR-uhl an-es-thee-zhuh]

injection of anesthetic drugs into the space around the spinal cord. This is used to numb the lower part of the body while allowing the patient to stay awake. See also anesthesia, spinal cord.

epiglottis [ep-uh-GLOT-is]

a thin, valve-like, cartilage structure at the root of the tongue that covers the glottis (the vocal cord area) when you swallow. This keeps food and drink from getting into the windpipe (trachea).

erectile dysfunction

also called ED or impotence. Not being able to have or keep an erection of the penis.

esophageal speech [eh-sof-uh-JEE-uhl]

a special way to speak used by some people after the voice box (larynx) has been removed. Air is swallowed and a “belching” type of speech can be produced. New devices, improved surgery, and the use of chemotherapy and radiation therapy instead of surgery have reduced the need to learn esophageal speech.

esophagus [ih-sof-uh-gus]

a hollow, muscular tube through which food passes from the mouth to the stomach. It lies behind the windpipe (trachea) and in front of the spine.


a hormone found in both men and women, but with higher levels in women. Often called the female sex hormone, it is made mostly by the ovaries, and in smaller amounts by the adrenal cortex. In girls, estrogen helps to regulate puberty, such as growth of breasts. In women, estrogen levels normally cycle on a monthly schedule to regulate menstruation and prepare the body for fertilization and reproduction. Estrogen may promote the growth of cancer cells in breast cancer. In men, estrogen is sometimes used to treat advanced prostate cancer by countering the action of testosterone. See also adrenal gland, estrogen receptor assay, estrogen therapy, hormone, hormone therapy, ovary.

estrogen receptor assay

a lab test done on a sample of the cancer to see whether estrogen receptors are present. The growth of normal breast cells and some breast cancers is stimulated by estrogen. Estrogen receptors are molecules that function as a cell’s “welcome mat” for estrogen circulating in the blood. Breast cancer cells without these receptors (called estrogen-receptor negative or ER-negative) are unlikely to respond to hormone therapy. Estrogen-receptor positive cancers are more likely to respond to hormone therapy. See also estrogen, hormone therapy.

estrogen therapy

the use of estrogen from other sources after a woman’s ovaries stop making it. This type of hormone therapy is used for short periods to relieve symptoms of menopause. Estrogen alone can raise the risk of endometrial cancer (cancer of the lining of the womb), so a women who still has a uterus (womb) is usually also given progesterone to lower this risk. Sometimes called estrogen replacement therapy, it can also increase breast cancer risk in some women. See also estrogen, menopausal hormone therapy, menopause, progesterone.

etiology [ee-tee-AHL-uh-jee]

the cause of a disease. There are many possible causes of cancer. Research is showing that both genetics (genes passed on from your parents) and lifestyle (including exposures to carcinogens) are major factors in many cancers. See also carcinogen, gene.

excision [ex-sih-zhun]

removal by cutting the body (surgery). This can mean cutting out a tumor or cutting off a body part.

expectant management

also called watchful waiting. In some cases of prostate cancer, close monitoring that is done instead of starting active treatment right away. This may be a reasonable choice for older men with small tumors that might grow very slowly. Because the man is being watched carefully, changes are noted quickly, and treatment can be started right away when needed.

external beam radiation therapy

also called EBRT. Radiation from a source outside the body that is focused on the cancer. It is much like getting an x-ray, but for a longer time. Compare to brachytherapy. See also radiation therapy.


false negative

test result implying a condition does not exist when in fact it does.

false positive

test result implying a condition exists when in fact it does not.

familial adenomatous polyposis [fa-mil-e-uhl ad-no-muh-tus or ad-uh-NO-muh-tus pa-lih-PO-sis]

also called FAP. An inherited condition that puts a person at risk for getting colorectal cancer when they are young. People with this syndrome develop many polyps in the colon and rectum as well as tumors in other parts of the body. Usually one or more of these polyps becomes cancer if it is not removed. FAP is caused by changes in the APC gene. See also APC gene, colon, gastrointestinal tract, polyp, rectum, tumor.

fascia [fash-uh]

a sheet or thin band of fibrous tissue that covers muscles and some organs of the body.

fat necrosis [nuh-crow-sis]

the death of fat cells, usually following injury. Fat necrosis is not cancer, but it can cause lumps and pulling of the tissues. When this happens in the breast, it can be confused with breast cancer.

fatigue [fuh-teeg]

a common symptom during cancer treatment, a bone-weary tiredness that doesn’t get better with rest. For some people, this can last for a long time after treatment.

fecal immunochemical test [fee-kuhl im-you-no-KIM-uh-kuhl test]

also called FIT. A test to look for hidden blood in the stool, which could be a sign of cancer. The test is not affected by vitamins or foods, though it still requires 2 or 3 stool samples to give accurate results. See also colorectal cancer screening, false positive, fecal occult blood test.

fecal occult blood test or FOBT

a test for hidden blood in the feces (stool). This may be a sign of cancer, or it could be blood from other sources. See also colorectal cancer screening, fecal immunochemical test.

feces [fee-sees]

solid waste matter; stool.

femur [fee-mer]

the thigh bone, which is the longest, largest, and strongest bone in the body. It extends from the hip (pelvis) to the knee.

fiber, dietary

includes a wide variety of plant carbohydrates that are not digested by humans. Fibers are grouped as soluble (like oat bran) and insoluble (like wheat bran). Beans, vegetables, whole grains, and fruits are good sources of fiber. Links between fiber intake alone and risk of cancer are not proven, but eating these foods is still recommended because they contain other substances that may help prevent cancer. They also have other health benefits.

fibroadenoma [fi-bro-ad-uh-NO-muh]

a breast tumor made of fibrous and glandular tissue that is not cancer. On a clinical breast exam or breast self-exam, it usually feels like a firm, round, smooth lump. These usually occur in young women. See also glandular tissue.

fibrocystic changes [fie-bro-SIS-tick]

a term that describes certain changes in the breast that are not cancer. Symptoms of this condition are breast swelling or pain. The doctor or nurse will look for nodules, lumpiness, or a discharge from the nipples. Because these symptoms or other signs can sometimes look like breast cancer, a mammogram or a biopsy of breast tissue may be needed to show that there is no cancer. See also biopsy, mammogram.

fibrosis [fie-bro-sis]

formation of scar-like (fibrous) tissue. This can happen anywhere in the body.

fibula [fib-yuh-luh]

a bone in the calf; the thinner, outside bone of the 2 bones in lower leg that go from the knee to the ankle. See also tibia.

fine needle aspiration biopsy [asp-er-A-shun by-op-see]

also called FNA or FNAB. A procedure in which a thin needle is used to draw up (aspirate) samples to look at under a microscope. See also aspiration, biopsy.

first-degree relative

a genetically related (blood-related) parent, sibling (brother or sister), or child.


see fluorescent in situ hybridization.

fistula [fist-chu-luh]

an abnormal passage, opening, or connection between 2 internal organs or from an internal organ to the outside of the body.

five-year relative survival rate

five-year relative survival rates compare the number of people who are still alive 5 years after their cancer was found to the survival of others the same age who don’t have cancer. This helps correct for other causes of death and is a better way to see the impact that cancer can have on survival. Still, these survival rates are not helpful in predicting any one person’s outcome. Five-year survival rates are based on the most recent information available, but they may include information from patients treated several years earlier. These numbers do not take into account advances in treatment that have often occurred. See also five-year survival rate.

five-year survival rate

the percentage of people with a given cancer who are alive 5 years or longer after diagnosis. Five-year survival rates are based on the most recent information available, but they may include information from patients treated several years earlier. These numbers do not take into account advances in treatment that have often occurred. They only paint a very general picture of how people in the past have done with the same type of cancer. Note that the 5-year survival rate counts survivors only, regardless of the cause of death (so some non-survivors will have died from causes other than cancer). These survival rates are not helpful in predicting any one person’s outcome. See also five-year relative survival rate.

flexible sigmoidoscopy

see sigmoidoscopy.

flow cytometry [sy-tahm-uh-tree]

a test of tumor tissue to see how fast the tumor cells are growing and if the tumor cells contain a normal or abnormal amount of deoxyribonucleic acid (DNA). This test is used to help predict how fast a cancer is likely to grow and spread. See also deoxyribonucleic acid, ploidy, s-phase fraction.

fluorescent in situ hybridization [floo-res-uhnt in sy-too hi-brid-ih-ZAY-shun]

a test that can help look at chromosomes. It uses special fluorescent dyes that only attach to certain parts of chromosomes and can find specific deoxyribonucleic acid (DNA) sequences. It can be used to diagnose, to evaluate prognosis (disease outlook), or to look at the remission of a disease. See also chromosome, cytogenetics, deoxyribonucleic acid, remission.

focus [fo-kus]

a point at which rays of light or radiation beams come together. Also used to describe a region of disease in the body. The plural can be focuses or foci (fo-sy).

follicle [fah-lick-uhl]

a sac or pouch-like structure. There are many types of follicles of all sizes in the body; for example, in the scalp, around the teeth, in lymph cells, in the thyroid, and in the ovaries. See also follicular.

follicular [fah-lick-yuh-ler]

relating to a follicle or follicles. In medicine, may refer to a type of cell in the thyroid, or to a type of cancer that starts in these follicular cells. It can also refer to a type of non-Hodgkin lymphoma (see also follicle, non-Hodgkin lymphoma).

fracture [frack-chur]

a partial or complete break, usually in bone.

free-PSA ratio

see percent-free PSA.

frozen section

a very thin slice of body tissue that has been quick-frozen for the pathologist to look at under a microscope while the patient is still in surgery. This method is sometimes used because it gives a quick diagnosis, and can tell a surgeon whether or not to continue with the procedure. The diagnosis is confirmed in a few days by a more detailed study called a permanent section. See also biopsy, permanent section, pathologist.


galactocele [guh-lack-tuh-seal]

a clogged milk duct; a cyst filled with milk. It may occur in the breast during breast-feeding. See also cyst, duct.


see ductogram.

Gardner syndrome

like familial adenomatous polyposis (FAP), Gardner syndrome is an inherited condition in which polyps develop at a young age and often lead to cancer. It can also cause benign (not cancerous) tumors of the skin, soft connective tissue, and bones. See also APC gene, familial adenomatous polyposis, polyp.

gastric [gas-trick]

of or referring to the stomach.

gastroenterologist [gas-tro-en-ter-AHL-uh-jist]

a doctor who specializes in diseases of the digestive (gastrointestinal) tract, such as the esophagus (swallowing tube), stomach, small intestine, and large intestine, as well as the liver, gallbladder, and pancreas. See also esophagus, large intestine, liver, pancreas, small intestine, stomach.

gastrointestinal stromal tumors [gas-tro-in-TEST-uh-nul stro-muhl too-mers]

also called GISTs. Tumors that grow from special cells on the intestinal wall known as the interstitial cells of Cajal. These tumors may or may not be cancer. GIST cancers are very different from other more common types of GI tract cancers in treatment and outlook. See also gastrointestinal tract.

gastrointestinal tract [gas-tro-in-TEST-uh-nul trakt]

also called the GI tract or the digestive tract. It is made up of those organs and structures that process and prepare food to be used for energy; for example, the stomach, small intestine, and large intestine.


a piece of deoxyribonucleic acid (DNA) that has information on inherited traits such as hair color, eye color, and height, as well as susceptibility to certain diseases. See also deoxyribonucleic acid, mutation.

gene therapy

a type of treatment being studied in which defective genes would be replaced with normal ones. The new genes could be delivered into the cells by viruses or proteins. See also gene.

genetic counseling

the process of counseling people who might have a gene that makes them more likely to develop cancer. The purpose of counseling is to explore what the genetic test results might mean, help them decide whether they wish to be tested, and support them before and after the test. See also gene, genetic counselor, genetic testing.

genetic counselor

a specially trained health professional who helps people as they consider genetic testing, as they adjust to the test results, and as they consider whatever screening and preventive measures are best for them. They can also help a person understand what their results may mean for other family members, See also genetic counseling, genetic testing.

genetic testing

tests that can be done to see if a person has certain gene changes known to increase cancer risk. Such testing is not recommended for everyone, but for people with certain types of family history. Genetic counseling should be part of the genetic testing process. See also genetic counseling.

genome [jee-nome]

the total deoxyribonucleic acid (DNA) and sometimes ribonucleic acid (RNA) in a single cell, representing all of the genetic information of the organism. The term genome can also refer to certain types of genetic material, such as that in the cell’s nucleus (nuclear genome) or mitochondria (mitochondrial genome). See also deoxyribonucleic acid, gene, ribonucleic acid.

germ cell

the reproductive cells of the body, that is, ova (eggs) or sperm. See also ova, sperm.

GI tract

see gastrointestinal tract.


a cell or group of cells that make and release substances to be used by the body or sent outside of it. The sweat glands are some examples of organs that make and release substances. See also duct, endocrine glands.

glandular cells [glan-juh-luhr]

the cells in a gland that make substances. For example, glandular cells in the prostate make the milky fluid which becomes part of the semen.

glandular tissue [glan-juh-luhr tish-oo]

tissue that makes and secretes a substance. For instance, the lobules of the breast are glandular tissue because they make breast milk. See also lobules.


the head of the penis.

Gleason grade

a number describing how abnormal prostate cancer cells look based on the Gleason system. A pathologist assigns a grade number from 1 through 5 based on how much the cancer cells under the microscope look like normal prostate cells. Those that look a lot like normal cells are graded 1, while those that look the least like normal cells are graded 5. See also Gleason score, grade, pathologist, prostate.

Gleason score or Gleason sum

the sum of the 2 Gleason grades used classify prostate cancer based on how the cells look under the microscope. Because prostate cancers often have areas with different grades, a grade is assigned to the 2 areas that make up most of the cancer. These 2 grades are added to give a Gleason score between 2 and 10. This is used along with other information to stage the cancer. The higher the Gleason score, the faster the cancer is likely to grow and the more likely it is to spread beyond the prostate. See also Gleason grade, prostate, staging.


the grade of a cancer tells how abnormal its cells look under the microscope. There are different grading systems for different types of cancers. Each grading system divides cancer into those that look the most normal, the least normal, and those in between. Grading is done by a pathologist who looks at sample tissue from the biopsy. Cancers with more abnormal-looking cells tend to grow and spread more quickly and have a worse prognosis (outlook). See also biopsy, pathologist, staging.

graft-versus-host disease [GVHD]

the condition that results when the immune cells of a transplant (usually a bone marrow or other type of stem cell transplant) from a donor attack the tissues of the person receiving the transplant. See also allogeneic stem cell transplant, bone marrow, hematopoietic stem cell transplant, stem cells, umbilical cord blood transplant.

gray [Gy]

a unit for measuring radiation transfer. See also radiation dose.

growth factors

naturally occurring proteins that make cells grow and divide. Too much growth factor production by some cancer cells helps them grow quickly. New treatments to block these growth factors are being tested in clinical trials. Other growth factors are sometimes used to help normal cells recover from side effects of chemotherapy.

guaiac [gwi-ack]

substance used to test stool to see if it contains blood. See also fecal occult blood test.

gynecologic oncologist [guy-nuh-kuh-LA-jik on-kahl-uh-jist]

a doctor who specializes in cancers of the female reproductive (sex) organs. See also cancer care team.

gynecologist [guy-nuh-KAHL-uh-jist]

a doctor who specializes in women’s health.

gynecomastia [guy-nuh-ko-MAST-tee-uh]

male breast enlargement, sometimes with breast tenderness; a possible side effect of some hormone treatments. See also hormone therapy.


HDR brachytherapy

see high-dose rate brachytherapy.

health care power of attorney

see durable power of attorney for health care.

hematochezia [he-muh-toe-KEEZ-ee-uh or hem-at-uh-KEEZ-ee-uh]

bright red blood in the stool.

hematocrit [he-mat-uh-krit]

the percentage of the blood volume made up of red blood cells. This can get low in people with cancer. The normal range varies by lab, but typically is around 37% to 52% of the blood volume.

hematologist [he-muh-TAHL-uh-jist]

a doctor who specializes in diseases of the blood and blood-forming tissues.

hematoma [he-muh-TOE-muh]

a collection of blood outside a blood vessel caused by a leak or an injury. A bruise is an example of a hematoma.

hematopoietic stem cell transplant [he-muh-toe-poi-ET-ick]

procedure used to restock the bone marrow when it has been destroyed by chemotherapy, radiation, or disease. Stem cells can be taken from bone marrow or circulating (peripheral) blood to be transfused into the patient. Stem cells may be the patient’s own (autologous), or may come from someone else (allogeneic). Allogeneic stem cell transplants can come from a matched donor or from the banked umbilical cord blood of a newborn. See also autologous stem cell transplant, allogeneic stem cell transplant, bone marrow, stem cells.

hematuria [he-muh-TUR-ee-uh]

blood in the urine.

hemicolectomy [hem-ee-ko-LEK-tuh-me]

surgical removal of part of the colon.

hemoglobin [HE-muh-glo-bin]

the part of the red blood cell that carries oxygen, which is often measured in a complete blood count. Hemoglobin can get very low in people with cancer, especially during certain kinds of treatment. Normal ranges vary by lab, but typically are around 12-18 gm/dL.

hemorrhoids [hem-uh-royds]

large varicose veins inside the rectum or colon. They don’t cause cancer or become cancer, but they can cause pain, itching, and irritation. They can also cause slight bleeding, which can result in a positive fecal occult blood test or fecal immunochemical test even when no cancer is present. See also colon, colorectal cancer screening, fecal immunochemical test, fecal occult blood test, rectum.

hepatomegaly [hep-at-o-MEG-uh-lee]

enlargement of the liver.

HER2 gene [sometimes called HER2/neu]

see human epidermal growth factor receptor 2.

hereditary cancer syndrome

conditions linked with cancers that occur in several family members because of an inherited, mutated gene. See also mutation, gene.

hereditary non-polyposis colon cancer [huh-RED-ih-ter-ee non-pah-lih-PO-sis]

also called HNPCC. An inherited condition that greatly increases a person’s risk for developing colorectal cancer, as well as endometrial cancer (cancer of the lining of the uterus), ovarian cancer, small bowel cancer, and cancer of the lining of the kidney or the ureters. People with this condition tend to develop cancer at a young age without first having many polyps. See also polyp.

hereditary prostate cancer genes

any of a number of genes that are linked to prostate cancer. Inherited deoxyribonucleic acid (DNA) changes in these genes may make prostate cancer more likely to develop in some men. Research on these genes is still in early stages, and genetic tests for most of them are not yet available. See also deoxyribonucleic acid, gene, prostate.


being unable to start the stream of urine right away.

high risk

when the chance of developing a disease such as cancer is much greater than that normally seen in the general population. People may be at high risk from many factors, including heredity (such as a family history of breast cancer), personal habits (such as smoking), age (older people get cancer more often), the environment (such as overexposure to sunlight), and many others.

high-dose rate or temporary brachytherapy [brake-ee-THER-uh-pee]

also called HDR brachytherapy. A form of treatment that puts a radioactive source into small plastic tubes or applicators near the cancer. The radioactive source is put in the applicators and taken out a few minutes later. The applicator may be left in place. This is usually repeated for a few days to a few weeks and may be used along with external beam radiation therapy. This is different from low-dose rate brachytherapy, which uses lower doses of radiation over a longer period of time and leaves the radioactive seeds in the body. Compare to low dose rate brachytherapy. See also brachytherapy, external beam radiation therapy.

histology [hiss-tah-luh-jee]

how cells or tissues look when studied under a microscope. The histologic examination of cells and tissues is done by a pathologist. See also pathologist.

Hodgkin disease

an often curable type of cancer that affects the lymphatic system. Formerly called Hodgkin’s disease. See also lymph node, lymphatic system.

home health nurse

a nurse who gives treatment or medicines in the home, teaches patients how to care for themselves, and assesses their condition to see if further medical attention is needed.

homogeneous [home-uh-JEE-ne-us]

cells or tissue that look the same throughout. See also histology.


a chemical substance released into the body by the endocrine glands such as the thyroid, adrenal, or ovaries. Hormones travel through the bloodstream and set in motion various body functions. Testosterone and estrogen are examples of male and female hormones. See also adrenal gland, endocrine glands, hormone therapy, ovary, thyroid.

hormone receptor

a protein located on a cell’s surface or within the cell cytoplasm that binds to a hormone. Tumors can be tested for hormone receptors to see if they can be treated with hormones or anti-hormones. See also hormone therapy, hormone receptor assay, estrogen receptor assay, progesterone receptor assay.

hormone receptor assay

a test to see if a breast tumor is likely to be affected by hormones or if it can be treated with hormones. See also estrogen receptor assay, progesterone receptor assay.

hormone replacement therapy

see menopausal hormone therapy.

hormone therapy

cancer treatment using drugs that interfere with hormone production or hormone action, or the surgical removal of hormone-producing glands. Hormone therapy may help kill or slow the growth of cancer cells that depend on hormones to grow. For example, it is a common form of treatment for certain breast and prostate cancers. See also androgen deprivation therapy, hormone receptor, hormone receptor assay.


any type of cancer that depends on hormones for survival, such as some breast and prostate cancers. See also hormone therapy, androgen-dependent, hormone receptor, hormone receptor assay.


not responsive to hormone treatments. See also androgen-independent, hormone therapy.


a special kind of care for people in the final phase of illness, as well as their families and caregivers. The care usually takes place in the patient’s home or in a home-like facility. See also palliative treatment.

hot flush or hot flash

sudden brief feeling of body warmth, along with flushing of the skin and sweating; common during menopause and androgen deprivation therapy. See also androgen deprivation therapy, menopause.

human epidermal growth factor receptor 2

a protein that is present in very small amounts on the outer surface of normal cells. HER2 stimulates cell growth, and cancers that produce too much of this protein tend to grow and spread faster. Drugs used to treat cancers that produce HER2 attach to the HER2 protein to slow the growth of the cancer cells.

human papilloma virus or human papillomavirus [pap-uh-LO-muh vy-rus]

also called HPV. A common virus with many types, some of which cause changes in the body’s cells that can grow into cancer. Of the more than 100 types of HPV, about 40 HPV types can live in the mucous membranes such as those of the vagina, cervix, and anus. Called genital HPV, a few of these types cause most cervical cancers. Genital HPV is spread mainly during vaginal, oral, or anal sex, from one person to another during skin-to-skin contact. In most cases, the body gets rid of the HPV infection, but for some people HPV can cause warts or cancer. Besides cervical cancer, some cancers of the penis, vagina, vulva, and urethra and some head and neck cancers (mostly the tongue and tonsils) may be related to HPV. The types most often linked to cancer include HPV-16, HPV-18, HPV-31, HPV-35, HPV-39, HPV-45, HPV-51, HPV-52, and HPV-58. About 70% of HPV-related cancers are caused by types 16 or 18. Vaccines can now help the body fight these 2 types, as well as 2 other types mainly known for causing warts. There is also a test for HPV that can be done along with a woman’s Pap test. See also Pap test.

humerus [hyoo-mer-us]

the long bone in the upper arm that goes from the shoulder to the elbow.

hyperalimentation [hi-per-al-ih-men-TAY-shun]

liquid nutrition given into a vein (intravenously or IV).

hyperplasia [hi-per-PLAY-zhuh]

too much growth of cells or tissue in a specific area, such as the lining of the prostate. See also benign prostatic hyperplasia, prostate.

hyperplastic polyp [hi-per-PLAS-tick pa-lip]

a growth found in the colon (large intestine) that is unlikely to become cancer. Some doctors think that certain hyperplastic polyps can become pre-cancerous, or may mean a risk of developing adenomatous polyps and cancer later, especially if the polyps are in the ascending colon. See also adenomatous polyp, ascending colon, polyp.

hypertension [hi-per-TEN-shun]

high blood pressure.

hyperthermia [hi-per-THERM-ee-uh]

high body temperature or fever. Treatments using hyperthermia treat disease or improve treatment outcomes by raising body temperature, or by raising the temperature of the affected body part.

hypertrophy [hi-per-truh-fee]

the enlargement of an organ or part due to an increase in the size of its cells.

hysterectomy [hiss-ter-EK-tuh-me]

an operation to remove the uterus. This can be done through an incision (cut) in the abdomen (belly), through a few small cuts in the lower belly (called laparoscopic hysterectomy), or through the vagina. The ovaries may be removed (oophorectomy) at the same time. See also uterus, oophorectomy, ovary, vagina.



see fecal immunochemical test.


see insulin-like growth factor-1.

ileostomy [ill-ee-OSS-tuh-me]

an operation in which the end of the small intestine, the ileum, is brought out through an opening called a stoma on the abdomen (belly). Stool that leaves the body through this opening tends to be unformed or liquid because it hasn’t been through the large intestine.

ileum [ill-ee-uhm]

the lower part of the small intestine. See also ileostomy.

image cytometry

a method that uses computers to analyze digital pictures of the cells from a microscope slide to check the number of sets of chromosomes in the cell. See also chromosome, ploidy.

imaging studies

methods used to make pictures of internal body structures. Some imaging tests used to help diagnose or stage cancer are x-rays, CT scans, magnetic resonance imaging (MRI), PET scans, and ultrasound.

immune system

the complex system by which the body resists infection by germs, such as bacteria or viruses, and rejects transplanted tissues or organs. The immune system may also help the body fight some cancers.

immunocytochemistry [im-yuh-no-sy-toe-KEM-iss-tree]

lab tests that use antibodies to detect specific chemical antigens in specially-prepared cells viewed under a microscope. These tests can be used to help detect and classify cancer cells. See also antibody, antigen, monoclonal antibodies.

immunohistochemistry [im-yuh-no-his-toe-KEM-iss-tree]

lab tests that use antibodies to detect specific chemical antigens in tissues viewed under a microscope. It is the most common method used for estrogen receptor assays and progesterone receptor assays on breast cancer tissue. See also antibody, antigen, monoclonal antibodies, estrogen receptor assays, progesterone receptor assays.

immunology [im-yuh-NAHL-uh-jee]

study of how the body resists infection and certain other diseases. Knowledge gained in this field is important to those cancer treatments that use the immune system and/or substances that behave like parts of the immune system to help fight cancer. See also immune system, immunotherapy.

immunosuppression [im-yuh-no-suh-PREH-shun]

a state in which the immune system is weak and unable to respond the way it should. This condition may be present at birth, or it may be caused by some infections (such as human immunodeficiency virus or HIV), cancer, or cancer treatments (such as chemotherapy and radiation). See also immune system.

immunotherapy [im-yuh-no-THER-uh-pee]

treatments that use the body’s immune system to fight cancer. This is done by boosting the patient’s own immune system or giving man-made versions of the immune system. See also immune system.


can refer to a small amount of radioactive material placed in or near a cancer. Also, can mean an artificial form used to restore the shape of an organ after surgery, for example, a breast implant. See also brachytherapy, prosthesis.

impotence [im-puh-tense]

not being able to have or keep an erection of the penis; also called erectile dysfunction (ED).


see intensity-modulated radiation therapy.

in situ [in sy-too]

in place; localized and confined to one area. A very early stage of cancer.

incidence [in-sih-dens]

the number of new cases of a disease that occur in a certain number of people each year. Compare to prevalence.

incision [in-sih-zhun]

cut made during surgery.


uncertain finding; a result that cannot say for certain whether a disease or condition is present; neither positive nor negative.

incontinence [in-kon-tuh-nence]

partial or complete loss of urinary or bowel control. See also urinary incontinence.

indigent [in-dij-ent]

not having enough money to meet one’s needs.

infiltrating ductal carcinoma

see invasive ductal carcinoma.

infiltrating lobular carcinoma

see invasive lobular carcinoma.

inflammatory bowel disease or IBD

a chronic condition (either ulcerative colitis or Crohn’s disease) in which the colon is inflamed over a long period of time and might have ulcers in its lining; IBD increases a person’s risk of colorectal cancer. Starting colorectal cancer screening earlier and doing the tests more often is recommended for people with IBD. (Note that IBD is not the same as IBS, or inflammatory bowel syndrome.) See also colon, Crohn’s disease, ulcerative colitis, colorectal cancer screening.

inflammatory breast cancer

a type of invasive breast cancer with spread to lymphatic vessels in the skin covering the breast. The skin of the affected breast is red, feels warm, and may thicken to look and feel like an orange peel. About 1% of invasive breast cancers are inflammatory breast cancers. Also called inflammatory carcinoma or IBC. See also invasive cancer, lymphatic system.

inflammatory polyp

polyps that commonly occur with some type of irritation or inflammation of the colon, such as ulcerative colitis. They do not seem to increase the risk of colorectal cancer, though the underlying condition can. See also colon, Crohn’s disease, polyp, ulcerative colitis.

informed consent

a full explanation of the course of treatment, the risks, benefits, and possible alternatives. After this process, the patient signs a form stating that they have received this information and that they agree to the procedure, surgery, or treatment.

infraclavicular [in-fruh-kluh-VICK-yuh-ler]

lymph nodes located under the collar bone (clavicle). See also clavicle, lymph node, supraclavicular.

ingest [in-jest]

to take in by mouth; to eat, drink, or swallow.

inherited disease

illness to which a person is susceptible because of a gene passed from his or her parents at birth. See also gene, genetic testing, mutation.


a person whose treatment requires staying in the hospital. Compare to outpatient.

insulin-like growth factor-1 [IGF-1]

hormone-like substance thought to affect growth hormone activity. Some studies have shown men with high blood levels of IGF-1 seemed more likely to develop prostate cancer, but not all studies agree. More research is needed.

integrated PET/CT

a scan that combines the cross-section x-rays of the CT with the ability to detect areas of high energy use. See also computed tomography scan, positron emission tomography scan.

intensity-modulated radiation therapy [IMRT]

an advanced method of conformal radiation therapy in which the beams are aimed from several directions, while the intensity (strength) of the beams is controlled by computers. This lets more radiation reach the treatment area while reducing the radiation to healthy tissues; in some cases, total radiation dose can be higher with IMRT. See also conformal radiation therapy, three-dimensional conformal radiation therapy.

interferon [in-ter-FEAR-on]

a protein produced by cells. Interferon helps regulate the body’s immune system, boosting activity when a threat, like a virus, is found. Scientists have learned that interferon helps fight against cancer, so it is used to treat some types of cancer. See also immune system, immunotherapy.

interleukins [IN-ter-loo-kins]

a group of chemical messengers (called cytokines) that can carry signals between cells. One type of interleukin-2 (IL-2) has been approved by the FDA to treat advanced kidney cancer and metastatic melanoma. It may be used alone or along with other forms of immunotherapy. IL-2 helps immune system cells grow and divide more quickly. Using IL-2 with chemotherapy or with other cytokines (such as interferon-alfa) may make these treatments work better against some cancers. See also chemotherapy, cytokine, immunotherapy, interferon.

intermittent hormone therapy

a type of prostate cancer treatment in which hormone drugs are stopped after a man’s blood prostate-specific antigen (PSA) level drops to a very low level and remains stable for a while. If the PSA level begins to rise, the drugs are started again. Another form of intermittent hormone therapy uses androgen suppression for fixed periods of time – for example, 6 months on followed by 6 months off. While this treatment approach may help reduce side effects, it is too soon to say whether it is better or worse than continuous hormonal therapy. See also androgen deprivation therapy, hormone therapy, prostate-specific antigen.

internal radiation

treatment in which a radioactive substance is implanted in the body. Compare to external beam radiation therapy. See also brachytherapy, implant.

interstitial radiation therapy [in-ter-STIH-shul]

a type of radiation treatment in which a radioactive implant is put right into the tissue (not in a body cavity). See also brachytherapy, radiation therapy.

intervertebral disc [IN-ter-ver-tuh-bruhl disk]

a gel-filled disc of cartilage that sits between bones of the spine (vertebrae) and allows them to move more easily. Discs also act as shock absorbers and have ligaments to hold the vertebrae together. See also vertebra, spinal cord.

intestines [in-test-ins]

the part of the digestive tract from the end of the stomach to the anus. This section absorbs nutrients and water from food into the bloodstream. It includes the small intestine, (small bowel), and the large intestine (large bowel), which includes the colon. See also anus, colon, digestive system, gastrointestinal tract, small intestine.

intraductal papillomas [in-truh-DUCK-tul pap-uh-LO-muhs]

small, finger-like, non-cancerous growths in the breast ducts that may cause a clear or bloody nipple discharge. These are most often found in women 45 to 50 years of age. A woman who has had papillomas has a slightly increased risk of breast cancer. See also duct.

intramucosal carcinoma

see carcinoma in situ.

intramuscular [IM]

injected into a muscle.

intraoperative ultrasound

a test done with sound waves after surgery has started and the abdomen (belly) is opened up. For example, the probe can be placed on the surface of the liver to see if cancer has spread inside it. See also ultrasound.

intravenous [in-truh-VEEN-us]

also called IV. A method of giving fluids and medicines using a needle or a thin tube (called a catheter) that is put into a vein.

intravenous pyelogram [in-truh-VEEN-us pile-uh-gram]

also called IVP. A special kind of x-ray procedure in which a dye is put into the bloodstream. The dye travels to the kidneys, ureters, and bladder and helps to clearly outline these organs on the x-rays. See also bladder, kidney, ureters.

invasive cancer

cancer that has spread beyond the layer of cells where it first began and has grown into nearby tissues. Compare to carcinoma in situ. See also malignant, metastasis.

invasive ductal carcinoma

also called infiltrating ductal carcinoma. A cancer that starts in the milk passages (ducts) of the breast and then breaks through the duct wall, where it invades the fatty tissue of the breast. When it reaches this point, it can spread (metastasize) elsewhere in the breast, as well as to other parts of the body through the bloodstream and lymphatic system. Invasive ductal carcinoma is the most common type of breast cancer, accounting for about 80% of all breast cancers. See also lymphatic system, metastasize.

invasive lobular carcinoma

also called infiltrating lobular carcinoma. A cancer that starts in the milk-producing glands (lobules) of the breast and then breaks through the lobule walls and grows into the nearby fatty tissue. From there, it may spread elsewhere (metastasize). About 15% of invasive breast cancers are invasive lobular carcinomas. This type of cancer is often hard to detect by physical exam or even on a mammogram. See also mammogram, metastasize.


under study. Often used to describe drugs or treatments used in clinical trials that are not yet available to the general public. See also clinical trials.

ionizing radiation

high-energy particles or rays which can cause electrons to split off atoms. Certain types of ionizing radiation (such as x-rays) are used in medical diagnosis to make pictures of what is inside the body. Carefully controlled radiation doses are used in cancer treatment to kill cancer cells and shrink tumors. Large doses of ionizing radiation can also cause cancer. See also radiation dose, x-ray.


see intravenous pyelogram.



a gene that can mutate into a cancer accelerator and allow the growth of colorectal cancer. This is not an inherited mutation (passed on from a parent), which would be in every cell in the body from birth. It is a spontaneous mutation that starts in a single cell which then grows and multiplies. See also colorectal cancer, gene, mutation.

Kegel exercises

exercises to strengthen certain muscles in the bottom of the pelvis. These exercises may help men and women with certain forms of urinary incontinence. See also urinary incontinence.


an organ that filters the blood to remove excess water, salt, and waste in the form of urine. A person normally has 2 kidneys. See also ureter, bladder, urethra.


lactation [lack-tay-shun]

production of milk in the breast.

laparoscope [LAP-uh-ruh-scope]

a long, flexible, thin tube put into the body through a very small cut. The laparoscope lets the surgeon see organs and lymph nodes inside the body. The lymph nodes, or even organs, can be removed using special surgical instruments that fit through the laparoscope. See also laparoscopic surgery, lymph node.

laparoscopic lymphadenectomy [lap-uh-ruh-SKAH-pick limf-ad-uh-NECK-tuh-me]

removal of lymph nodes with a laparoscope. See also laparoscope, lymph node.

laparoscopic radical prostatectomy [lap-uh-ruh-SKAH-pick rad-ick-uhl pros-tuh-TECK-tuh-me]

a surgical procedure in which the prostate is removed using a laparoscope. As of late 2011, long-term studies are not yet available comparing survival for men who had this procedure with those who had open surgery to remove their prostates. See also laparoscope, prostate.

laparoscopic surgery [lap-uh-ruh-SKAH-pick]

surgery using a narrow tube-like instrument called a laparoscope that is put through a small incision (cut). Other tubes are put in other nearby incisions to allow the surgeon to work inside the body. A surgeon might use this method to remove part of the colon or other organ while watching the procedure on a TV monitor. The small incisions led to the name “keyhole surgery” or minimally invasive surgery. This surgery is more difficult than traditional surgery, and requires a skilled surgeon who has done a lot of them. See also colon, laparoscope.

laparoscopy [lap-uh-RAHS-kuh-pee]

examination of a body cavity with an instrument called a laparoscope. See also laparoscope.

large cell lung cancer

see non-small cell lung cancer (NSCLC).

large intestine

the lower part of the intestine, into which the small intestine empties. The large intestine contains the cecum, colon, and rectum. See also cecum, colon, rectum.

laryngectomy [lair-en-JEK-tuh-me]

surgery to remove the voice box (larynx), usually because of cancer.

laryngopharynx or hypopharynx [luh-rin-jo-FAIR-ingks or hi-po-FAIR-ingks]

the lower part of the pharynx. This is the part of the throat that extends downward from the voice box to the swallowing tube (esophagus).

latissimus dorsi flap procedure [la-tiss-ih-mus dors-eye]

a method of breast reconstruction in which a long flat muscle of the back and the attached skin are moved into the breast area. This method almost always uses a breast implant. See also breast reconstruction, breast implant.

laxative [lack-suh-tiv]

a medicine that helps make stool (feces) easier to pass (promotes defecation) to prevent or treat constipation. Many are taken by mouth, but some come as a suppository which is put in the rectum. Laxatives work in different ways; for example, by pulling fluid into the intestine or irritating the bowel to stimulate movement. Others add bulk (such as fiber), soften the stool, or lubricate it for easier passage.

leiomyoma [lie-o-my-O-muh]

also called uterine fibroid tumor or fibroma, a benign (not cancer) fibrous tumor of the uterus (womb). About 40% of women have leiomyomas by age 40. Usually there are no symptoms, but the tumors can cause abnormal uterine bleeding and other symptoms depending on their size and location in the uterus. See also tumor, uterus.

lesion [lee-zhun]

an area of abnormal body tissue. May be used to describe a lump, mass, or tumor; also a spot or change in the appearance or texture of skin, such as an open sore, scab, bump, or discolored area. See also mass, tumor.

leukemia [loo-key-me-uh]

cancer of the blood or blood-forming organs. There are 2 major classes of leukemia, myeloid and non-myeloid types. People with leukemia often have a very high number of white blood cells (leukocytes). See also leukocytosis, myeloid leukemia, non-myeloid cancers, white blood cells.

leukocyte [LOO-ko-site]

white blood cell. See also white blood cells.

leukocytosis [loo-ko-sy-TOE-sis]

having more than the usual number of white blood cells. See also white blood cells.

leukopenia [loo-ko-PEE-nee-uh]

decrease in the white blood cell count, common in people with cancer, and often a side effect of chemotherapy. See also chemotherapy, white blood cells.

leukoplakia [loo-ko-PLAY-key-uh]

white patches on the tongue or inside the cheeks. These are often pre-cancers.


see luteinizing hormone.


see luteinizing hormone-releasing hormone.

LHRH agonists

see luteinizing hormone-releasing hormone analogs.

LHRH analogs

see luteinizing hormone-releasing hormone analogs.

LHRH antagonists

see luteinizing hormone-releasing hormone antagonists.

libido [lih-be-doe or lih-by-doe]

sex drive.

limited breast surgery

also called lumpectomy, segmental excision, and tylectomy. Surgery to remove the breast cancer and a small amount of tissue around the cancer, but keep most of the breast. It is almost always combined with axillary (underarm) lymph node removal and is usually followed by radiation therapy. See also axillary dissection, lymph node, radiation therapy.

linear accelerator

also called a linac. A machine used for external-beam radiation therapy to treat cancer. It gives off gamma rays (or gamma photons) and electron beams. See also external-beam radiation therapy.


a tumor made of fatty tissue. It is not cancer. See also tumor.

living will

a legal document that allows a person to decide what should be done if he or she becomes unable to make health care decisions; a type of advance directive. Compare to durable power of attorney for health care. See also advance directives.

lobectomy [low-bek-tuh-me]

surgery to remove a lobe of an organ – usually the lung.

lobular carcinoma in situ [lob-yuh-lur car-sin-O-ma in sy-too]

also called LCIS. Although not a true cancer, it is sometimes listed as a non-invasive type of breast cancer. It starts within the milk-producing glands (lobules) of the breast but does not grow through the wall of the lobules. It does not become an invasive cancer very often, but having LCIS places a woman at somewhat higher risk of developing an invasive breast cancer later in life. Women need a yearly mammogram and clinical breast exam after LCIS. Women with LCIS might also want to ask their doctors about the benefits and limits of yearly screening with magnetic resonance imaging (MRI). See also clinical breast examination, invasive lobular carcinoma, magnetic resonance imaging (MRI), mammogram.

lobules [lob-youlz]

the glands in a woman’s breasts that produce milk.

local anesthesia

see anesthesia.

local excision [lo-kul eck-si-zhun]

surgery to remove small superficial (surface) cancers or polyps. See also polyp.

local recurrence

see recurrence.

local therapy

treatment of cancer at its site, so that the rest of the body is not affected. Surgery and radiation are examples of local therapy. Compare to systemic therapy.

local transanal resection [lo-kul tranz-a-nuhl re-sek-shun]

rectal cancer surgery that is done with instruments put in through the anus, without cutting the abdomen (belly). It can be used to cut through all layers of the rectum to remove invasive cancers as well as some normal rectal tissue. Compare to low anterior resection. See also anus, invasive cancer, rectum.

localized cancer

also called local cancer. A cancer that is confined to the organ where it started; that is, it has not spread to distant parts of the body. Compare to distant cancer, metastasis.

low anterior resection [low an-teer-ee-yer re-sek-shun]

a surgical approach used for cancers in the upper two-thirds of the rectum, close to where it connects to the colon. The incision (cut) is made through the abdomen (belly) only, and the cancer is removed along with a margin (edge) of normal tissue, lymph nodes, and fatty and fibrous tissue around the rectum. The colon is re-attached to the part of the rectum that is left so that a colostomy is not needed. See also colo-anal anastomosis, colon, colostomy, lymph node, rectum.

low-dose rate brachytherapy [brake-ee-THER-uh-pee]

also called LDR brachytherapy or permanent brachytherapy. Treatment in which pellets or seeds of radioactive material are placed inside thin needles, and put into the cancerous area. The needles are removed and the pellets (seeds) are left in place and give off low doses of radiation for weeks or months. Often used for prostate cancer, in which the pellets are put through the skin of the perineum (behind the scrotum) into the prostate. Compare to high-dose rate brachytherapy. See also perineum, prostate.

lower GI series

a series of x-rays of the intestines taken after a barium enema is given. See also barium enema, x-ray.

lumbar puncture or LP

procedure in which a thin needle is placed between the bones of the spine (vertebrae) and into the spinal canal to withdraw a small amount of spinal fluid or to give medicine into the central nervous system (brain and spinal cord) through the spinal fluid. Sometimes called a spinal tap. See also vertebra, spinal cord.


any kind of mass in the body. See also mass, tumor.

lumpectomy [lump-eck-tuh-me]

surgery to remove a breast lump and a small amount of nearby normal tissue. See also breast conservation therapy.

luteinizing hormone [LOO-tee-uh-ny-zing]

also called LH. Pituitary hormone that stimulates the testicles to make testosterone. See also hormone, pituitary, testicles, testosterone.

luteinizing hormone-releasing hormone [LOO-tee-uh-ny-zing]

also called LHRH or gonadotropin-releasing hormone. A hormone made by the hypothalamus, a tiny gland in the brain that affects levels of luteinizing hormone in the body and therefore affects testosterone levels. See also luteinizing hormone, testosterone.

luteinizing hormone-releasing hormone analogs [LOO-tee-uh-ny-zing]

also called LHRH analogs; sometimes called gonadotropin-releasing hormone (GnRH) analogs. Man-made hormones, chemically similar to luteinizing hormone-releasing hormone (LHRH). They stop the body from making the male hormone testosterone and are sometimes used to treat prostate cancer.. See also androgen deprivation therapy, luteinizing hormone, luteinizing hormone-releasing hormone antagonists, prostate.

luteinizing hormone-releasing hormone antagonists [LOO-tee-uh-ny-zing]

also called LHRH antagonists or gonadotropin-releasing hormone (GnRH) antagonists. A type of drug thought to work in a way much like the LHRH analogs, which may be able to lower testosterone levels more quickly without causing the tumor symptoms to worsen (this is called tumor flare). See also androgen deprivation therapy, luteinizing hormone-releasing hormone, luteinizing hormone-releasing hormone analogs, testosterone.

lycopenes [lie-kuh-peenz]

vitamin-like antioxidants that help prevent damage to deoxyribonucleic acid (DNA). Once thought to help lower prostate cancer risk, more recent studies have found no link between lycopene levels and prostate cancer risk. These substances are found in tomatoes, pink grapefruit, and watermelon. See also antioxidants, deoxyribonucleic acid.

lymph [limf]

clear fluid that flows through the lymphatic vessels and contains white blood cells called lymphocytes. These cells are important in fighting infections and may also have a role in fighting cancer. See also lymph node, lymphatic system, lymphocyte, immune system.

lymph node [limf node]

Small bean-shaped collection of immune system tissue, such as lymphocytes, found throughout the body along lymphatic vessels. They remove cell waste, germs, and other harmful substances from lymph. They help fight infections and also have a role in fighting cancer, although cancers can spread through them. Sometimes called lymph glands. See also immune system, lymph, lymphatic system.

lymph node biopsy

a test in which all or part of a lymph node is removed and looked at under a microscope to find out if cancer has reached the lymph nodes. See also biopsy, lymph node.

lymph node dissection

see lymphadenectomy.

lymphadenectomy [limf-ad-uh-NECK-tuh-me]

also called lymph node dissection. Surgical removal of one or more lymph nodes. After removal, the lymph nodes are looked at under a microscope to see if cancer has spread to them. See also lymph, lymph node, lymphatic system, lymphocyte.

lymphatic system [limf-at-ick]

the tissues and organs (including lymph nodes, spleen, thymus, and bone marrow) that produce and store lymphocytes (white blood cells that fight infection) and the channels or vessels that carry the lymph fluid. The entire lymphatic system is an important part of the body’s immune system. Invasive cancers sometimes get into the lymphatic vessels and spread (metastasize) to lymph nodes. See also bone marrow, invasive cancer, lymph, lymph node, lymphocyte, thymus, spleen.

lymphedema [limf-uh-DEE-muh]

a complication in which fluid collects in the arms, legs, or other part of the body. This can happen after the lymph nodes and vessels are removed by surgery, injured by radiation, or blocked by a tumor that slows the normal fluid drainage. Lymphedema can happen even years after treatment and may be a life-long problem. See lymph, lymph node, lymphatic system.

lymphocyte [limf-o-site]

a type of white blood cell that helps the body fight infection. See also white blood cells.

lymphocytosis [limf-o-sy-TOE-sis]

having an excess of lymphocytes. See also lymphocyte.

lymphokine [limf-o-kine]

see cytokine.

lymphoma [lim-foam-uh]

a cancer of the lymphatic system, a network of thin vessels and nodes throughout the body that helps to fight infection. Lymphoma involves the type of white blood cells called lymphocytes. The 2 main types of lymphoma are Hodgkin disease and non-Hodgkin lymphoma. See also Hodgkin disease, lymph node, lymphatic system, lymphocyte, non-Hodgkin lymphoma, white blood cells.

Lynch syndrome

an old term used to describe hereditary non-polyposis colorectal cancer (HNPCC); an inherited tendency to develop certain cancers. See also hereditary non-polyposis colorectal cancer.


macroglobulinemia [mack-row-glob-yuh-lin-EE-mee-uh]

a condition with abnormally large proteins in the blood, which may reduce or clog blood flow in the smaller blood vessels. Waldenstrom macroglobulinemia is a type of non-Hodgkin lymphoma with such proteins. See also non-Hodgkin lymphoma, Waldenstrom macroglobulinemia.

macrophage [mack-ro-faj]

a type of white blood cell that engulfs and destroys foreign materials. See also white blood cells.

magnetic resonance imaging [MRI]

a method of taking pictures of the inside of the body. Instead of using x-rays, MRI uses a powerful magnet to send radio waves through the body. The images appear on a computer screen as well as on film. Like x-rays, the procedure is physically painless, but some people may feel confined inside the MRI machine. See also imaging studies, x-ray.

malignant [muh-lig-nunt]

cancerous; dangerous or likely to cause death if untreated. Compare with benign. See also cancer.

malignant tumor [muh-lig-nunt too-mer or tyoo-mer]

a mass of cancer cells that may invade nearby tissues or spread (metastasize) to distant areas of the body. Not all cancers form tumors. See also malignant, tumor.

mammary lymph nodes

lymph nodes that are inside the chest near the sternum or breastbone. See also lymph nodes.

mammogram, mammography [MAM-uh-gram, mam-ah-gruff-ee]

an x-ray of the breast; a method of finding breast cancer that can’t be felt using the fingers. Mammograms are done with a special type of x-ray machine used only for this purpose. A mammogram can show a developing breast tumor before it’s big enough to be felt by a woman or even by a highly skilled health care professional. Screening mammography is used to help find breast cancer early in women who don’t have any symptoms. Diagnostic mammography helps the doctor learn more about breast masses or the cause of other breast symptoms. See also screening, x-ray.


any plastic surgery to rebuild the breast or to change the shape, size, or position of the breast. Reduction mammoplasty reduces the size of the breast. Augmentation mammoplasty enlarges a woman’s breast, usually with implants. See also breast reconstruction, implants.

margin [mar-jin]

in cancer surgery or biopsy, the tissue beyond the visible edge of the tumor or abnormal tissue that is removed along with the tumor or abnormality, in an effort to get all of the cancer. See also surgical margin.


any sort of lump, which may or may not be cancer. See also tumor.

mastectomy [mas-tek-tuh-me]

surgery to remove all or part of the breast and sometimes other tissue. There are several types of mastectomies.
  • Modified radical mastectomy removes the breast, skin, nipple, areola, and most of the axillary lymph nodes on the same side, leaving the chest muscles intact.
  • Partial or segmental mastectomy removes only the part of the breast that has the cancer and a margin of healthy breast tissue surrounding the tumor.
  • Prophylactic mastectomy is a mastectomy done before any evidence of cancer can be found, for the purpose of preventing cancer.
  • Quadrantectomy (quad-runt-EK-tuh-me) is a partial mastectomy in which the quarter of the breast that has a tumor is removed.
  • Simple mastectomy or total mastectomy removes only the breast and areola.
Compare to lumpectomy. See also axillary dissection, lymph node, sentinel node biopsy.

mastitis [mass-tie-tiss]

inflammation or infection of the breast.

mediastinal [me-dee-uh-STY-nul]

related to a part of the body that lies between other parts. In cancer care, often refers to the center of the chest. See also mediastinum.

mediastinoscopy [me-dee-uh-stine-AH-skuh-pee]

examination of the chest cavity using a thin, lighted, flexible tube inserted under the chest bone (sternum). This lets the doctor see the lymph nodes in this area and remove samples to check for cancer. See also biopsy, lymph node.

mediastinum [me-dee-uh-STY-num]

any structure or area of the body that is between other parts, such as the nasal septum that separates the 2 nostrils. Commonly refers to the central part of the chest, which is surrounded by the breastbone, the backbone, and both lungs. The chest mediastinum contains the heart, large blood vessels, trachea, esophagus, and lymph nodes. See also lymph nodes.

medical oncologist [med-ih-kull on-kahl-uh-jist]

a doctor who is specially trained to diagnose and treat cancer with chemotherapy and other drugs. See also cancer care team, chemotherapy.

medical power of attorney

see durable power of attorney for health care.

medullary carcinoma [MED-you-lair-ee]

a special type of invasive ductal carcinoma with especially sharp boundaries between tumor tissue and normal tissue. About 5% of breast cancers are medullary carcinomas. The outlook (prognosis) for this kind of cancer is considered better than average. See also invasive ductal carcinoma.

melanoma [mel-uh-NO-muh]

a cancerous (malignant) tumor that begins in the cells that make the skin coloring (these cells are called melanocytes). Melanoma is almost always curable when found early. But it is likely to spread, and once it has spread to other parts of the body the chances for a cure are much lower.

menarche [men-ar-key or men-ar-key]

a woman’s first menstrual period. Early menarche (before age 12) is a risk factor for breast cancer, possibly because the earlier a woman’s periods begin, the longer she is exposed to estrogen. See also estrogen, risk factor.

menopausal hormone therapy

the use of estrogen and progesterone from an outside source after the body has stopped making its own supply because of natural or induced menopause. This type of hormone therapy is sometimes given to relieve symptoms of menopause. Studies have found that taking estrogen and progesterone together increases breast cancer risk, as well as the risk of heart disease and blood clots. See also estrogen, estrogen therapy, menopause, progesterone.

menopause [men-uh-paws]

the phase in a woman’s life when monthly cycles of menstruation stop. During this time, hormone levels typically fluctuate before they stabilize at much lower levels. Menopause usually takes place in women in their late 40s or early 50s, but it can also be brought on suddenly by surgical removal of both ovaries (oophorectomy), or by some chemotherapies that destroy ovarian function. See also chemotherapy, estrogen, hormone, ovary.

messenger RNA

the molecule that carries the information from the deoxyribonucleic acid (DNA) genetic code to the parts of the cell that make proteins. See also deoxyribonucleic acid, ribonucleic acid.

metachronous [muh-tack-ruh-nus]

happening at different times. Compare to synchronous.

metastasis [meh-tas-tuh-sis]

cancer cells that have spread to one or more sites elsewhere in the body, often by way of the lymph system or bloodstream. Regional or local metastasis is cancer that has spread to the lymph nodes, tissues, or organs close to where the cancer started (the primary site). Distant metastasis is cancer that has spread to organs or tissues that are farther away (such as when lung cancer spreads to the brain).The plural of this word is metastases (meh-tas-tuh-sees). See also cancer, lymph node, lymph system, primary site.

metastasize [ meh-TAS-tuh-size]

the spread of cancer cells to one or more sites elsewhere in the body, often by way of the lymph system or bloodstream. See also lymph system, metastasis.

metastatic [meh-tuh-STAT-ick]

a way to describe cancer that has spread from the primary site (where it started) to other structures or organs, nearby or far away (distant). See also metastasis, primary site.


also written as m. A metric measure of length. It takes about 39.37 inches (or 100 centimeters) to equal 1 meter. See also centimeter, millimeter.


see calcifications.

micrometastases [mike-row-muh-TAS-tuh-sis]

the spread of cancer cells in groups so small that they can only be seen under a microscope.

microsatellite instability [my-crow-SAT-uh-lite in-stuh-BILL-uh-tee]

also called MSI. A type of genetic mutation often linked to hereditary non-polyposis colon cancer (HNPCC). This mutation causes size differences in sections of deoxyribonucleic acid (DNA) that are normally the same size in all a person’s cells. Testing for MSI is done on tissue taken from the cancer to find out if the DNA is of different lengths; if it is, HNPCC genetic testing is usually offered. See also deoxyribonucleic acid, genetic testing, hereditary non-polyposis colon cancer, mutation.

microvascular surgery

an operation that uses a microscope to see and attach very tiny blood vessels to each other.

microwave therapy

a way of treating cancer in a few sites, such as the liver, by using heat to destroy the cells. See also ablation.


also written as mm. A metric measure of length that is 1/1000 of a meter. 10 mm equals 1 centimeter, and 1,000 mm equals a meter. It takes about 25 mm (or 2.5 cm) to equal 1 inch. See also centimeter, meter.


unit of radiation exposure. See also radiation dose.


unit of radiation exposure. See also radiation dose.


an allogeneic bone marrow or stem cell transplant in which lower doses of conditioning treatment are used before the transplant. This allows some of the patient’s own bone marrow stem cells to survive, which lowers the risk of very low blood counts during engraftment. The new stem cells kill off the patient’s stem cells over time, after the transplant engrafts or “takes.” See also allogeneic stem cell transplant, bone marrow, hematopoietic stem cell transplant, reduced-intensity conditioning, stem cells.

modified radical mastectomy

see mastectomy.

monoclonal antibodies [ma-nuh-KLO-nuhl]

man-made antibodies that are designed to lock onto certain antigens (substances that can be recognized by the immune system). Monoclonal antibodies have several uses in diagnosing and treating cancer. Monoclonal antibodies that have been attached to chemotherapy drugs or radioactive substances are able to seek out antigens unique to cancer cells and deliver these treatments directly to the cancer, which kills the cancer cell without harming healthy tissue. “Naked” monoclonal antibodies can attach to cancer cells so that the cancer cells can be found and attacked by the immune system. Research is still going on to learn more ways they can be used to treat cancer. Monoclonal antibodies are also often used to help detect and classify cancer cells under a microscope. Other studies are being done to see if radioactive atoms attached to monoclonal antibodies can be used in imaging tests to detect and locate small groups of cancer cells. See also antibody, antigen, chemotherapy, imaging studies, immunocytochemistry.

morbidity [mor-bid-ih-tee]

rate of disease in a population or group; the number of people who have a disease or condition. See also incidence, prevalence.

morphology [mor-fol-uh-jee]

in cancer, how cells look under the microscope, including shape, structure, pattern, color, and other aspects of their appearance. See also pathologist.

mortality [mor-tal-uh-tee]

a measure of the rate of death from a disease within a given group of people.


see magnetic resonance imaging.

mucinous carcinoma [mew-sin-us car-sin-O-ma]

a type of carcinoma that is formed by mucus-producing cancer cells. See also carcinoma.

mucosa [mew-ko-suh]

see mucous membrane.

mucositis [mew-ko-site-us]

inflammation of a mucous membrane, such as the lining of the mouth. See also mucous membrane.

mucous membrane

also called mucosa. The moist inner lining layer of the mouth, throat, eyelids, nose, urethra, vagina, and digestive system.

mucus [mew-kus]

the thick fluid secreted by mucous membranes and glands.

multidrug resistance [MDR]

resistance of cancer cells to several unrelated drugs after being exposed to a single chemotherapy drug. May also refer to infections that can no longer be cured by the usual antibiotics. See also chemotherapy.

multiple myeloma

a type of cancer that starts in the plasma cells. Normal plasma cells are found in the bone marrow and are an important part of the body’s immune system. When plasma cells grow out of control, they can form a tumor, usually in the bone marrow. This type of tumor is called a myeloma, and if there are many tumors the cancer is called multiple myeloma. If there is only one tumor, it is called solitary plasmacytoma. See also bone marrow, immune system.

muscularis mucosae [mus-kyu-LAIR-is myoo-ko-say]

the inner muscle layer of the digestive tube (intestine) that is between the mucosa and the submucosa. See also colon, colon wall.

muscularis propria [mus-kyu-LAIR-is pro-pree-uh]

the muscle layer that covers most parts of the intestine (digestive tube). This layer is furthest away from the center of the tube. Moving outward from the opening, the muscularis propria is beneath the submucosa. Beyond the submucosa is a thin layer of tissue called subserosa, which covers the colon but not the rectum. See also colon, colon wall, intestine, rectum.

mutation [mew-tay-shun]

a change in the deoxyribonucleic acid (DNA) of a cell. Most mutations do not cause cancer, and a few may even be helpful. But all types of cancer are thought to be due to mutations that damage a cell’s DNA. Some cancer-related mutations can be inherited (passed on from a parent). This means that the person is born with the mutated DNA in all the body’s cells. But most mutations happen after the person is born. These are called somatic or acquired mutations. This type of mutation happens in one cell at a time, and only affects cells that arise from the single mutated cell. See also cancer susceptibility genes, deoxyribonucleic acid, gene, inherited mutation, somatic mutation.

myeloablative treatment [my-uh-lo-uh-BLAY-tiv]

treatment to wipe out the bone marrow before a bone marrow or stem cell transplant. See also bone marrow, hematopoietic stem cell transplant, conditioning treatment.

myeloid leukemia [my-uh-loid loo-key-me-uh]

also called myelocytic leukemia, myelogenous leukemia, or non-lymphocytic leukemia. A type of cancer that starts in the cells that are supposed to mature into different types of blood cells. Myeloid leukemia can be chronic (CML) or acute (AML). There are a number of subtypes of acute myeloid leukemia, some with genetic abnormalities that can affect the outlook for successful treatment. See also leukemia, non-myeloid cancers.


nasopharynx [nay-zoh-FAIR-ingks]

the part of the throat that lies above and behind the soft palate, behind the structures of the nose. Compare to oropharynx, pharynx.

necrosis [nuh-crow-sis]

the death of one or more cells of the body. Necrotic refers to tissue that has died.

needle aspiration [need-ul asp-er-A-shun]

to draw out a liquid, gas, or tissue fragments using suction. In this procedure, a needle is used to reach the cyst or tumor, and with suction, draw up (aspirate) samples to be looked at under a microscope. See also biopsy, needle biopsy.

needle biopsy [need-ul by-op-see]

removal of fluid, cells, or tissue with a needle so that it can be looked at under a microscope. The main types of needle biopsy are fine needle aspiration (FNA) and core biopsy. FNA uses a thin needle to draw up (aspirate) fluid or small tissue pieces from a cyst or tumor. A core needle biopsy uses a thicker needle to remove a core of tissue from a tumor. See also biopsy, needle aspiration.

needle localization [need-ul lo-cull-ih-ZAY-shun]

a procedure used to guide a surgical biopsy when the lump is hard to find or when there are areas that look suspicious on the x-ray but there is no distinct lump. A thin needle is placed into the area. X-rays are taken and used to guide the needle to the suspicious area. The surgeon then uses the path of the needle as a guide to find the abnormal area to be removed. See also biopsy, x-ray.


a result from lab tests or pathology findings in which the abnormality being looked for was not found. When lymph nodes or other tissues are found to be negative for cancer, it means that no cancer was found there. See also lymph nodes.

negative margin

see surgical margin.

neoadjuvant therapy [nee-o-AD-juh-vunt]

treatment given before the main treatment. For example, neoadjuvant hormone therapy is sometimes used to shrink a prostate tumor before brachytherapy to make the brachytherapy more effective. Compare to adjuvant therapy. See also brachytherapy, hormone therapy, prostate.

neonatologist [nee-o-nay-TAHL-uh-jist]

a doctor who specializes in the care of the newborn baby (until they are about 6 weeks old).

neoplasia [nee-o-PLAY-zee-uh]

the process of forming an abnormal new growth. The growth can be benign (not cancer) or malignant (cancer). See also neoplasm, tumor.

neoplasm [NEE-o-plaz-um]

an abnormal growth (tumor) that starts from a single altered cell. A neoplasm may be benign (not cancer) or malignant (cancer). Such a growth may be described as a neoplastic (NEE-o-plas-tik) tumor. See also cancer, mutation, tumor.

nephrologist [neh-frahl-uh-jist]

a doctor who specializes in diseases of the kidneys.

nerve-sparing prostatectomy

surgery to remove the prostate in which the surgeon tries to save a man’s ability to have erections by leaving in the neurovascular bundles that control that function. See also neurovascular bundle, prostate, radical prostatectomy.

neuropathy [nur-ah-puth-ee]

nerve abnormality or damage which causes numbness, tingling, pain, muscle weakness, or even swelling. It may be caused by injury, infection, disease (cancer, diabetes, kidney failure, or poor nutrition, for example), or by drugs. Peripheral neuropathy is a type of neuropathy that starts in nerves farthest away from the brain, such as the hands and feet.

neurosurgeon [nur-o-SUR-jun]

a doctor specializing in operations to treat nervous system disorders, which includes problems in the brain, spinal cord, and nerves. See also spinal cord.

neurovascular bundles [nur-o-VAS-kyu-lur]

groups of nerves and blood vessels that run along each side of the prostate and help the penis become erect. Removal or injury of these bundles during surgery, or damage from radiation therapy, can lead to impotence. Women also have these nerve bundles that run along both sides of the vagina and affect erectile tissue in the genital area. See also impotence, nerve-sparing prostatectomy, prostate.

neutropenia [new-trow-PEEN-ee-uh]

a decrease in the number of neutrophils (white blood cells that respond quickly to infection) in the blood. If a person has less than 1,500 cells/mm3 neutrophils, he or she is considered to be neutropenic and at risk for infection. With fewer than 500 cells/mm3 the risk of infection is very high and gets higher the longer the neutropenia lasts. See also white blood cells.

neutrophils [new-trow-fills]

white blood cells that fight bacteria infections. See also white blood cells.


the tip of the breast; the pigmented projection (bump) in the center of the areola. The nipple contains the opening of milk ducts from the breast. See also areola, duct.

nipple discharge

any fluid of any color coming from the nipple.

nipple retraction

an inward turning of the nipple of the breast.

nocturia [nok-toor-ee-uh]

excessive urination during the night.

nodal status

indicates whether the cancer has spread to lymph nodes (node-positive) or has not spread to lymph nodes (node-negative). See also lymph node.


see lymph node.

nodule [nod-yool]

a small, solid lump that can be felt. This term is sometimes used to refer to a small tumor seen on x-ray. See also tumor, x-ray.

non-Hodgkin lymphoma

formerly called non-Hodgkin’s lymphoma. A cancer of the lymphatic system (a network of thin vessels and nodes throughout the body that serves as part of the immune system). The difference between non-Hodgkin lymphoma and Hodgkin disease is the Reed-Sternberg cell, which is absent in non-Hodgkin lymphoma cells. See also Hodgkin disease, immune system, lymphatic system.

non-myeloid cancers

all cancers other than myeloid leukemias. Non-myeloid cancers include all types of carcinoma, all types of sarcoma, melanoma, lymphomas, lymphocytic leukemias (ALL and CLL), and multiple myeloma. See also carcinoma, leukemia, lymphoma, melanoma, multiple myeloma, myeloid leukemia, sarcoma.

non-small cell lung cancer

also called NSCLC. One of the main classes or categories of lung cancer, based on how the cells look under the microscope. Non-small cell lung cancer includes 3 major types: squamous cell (or epidermoid) carcinoma, adenocarcinoma, and large cell (undifferentiated) carcinoma of the lung. See also carcinoma. Compare to small cell lung cancer.

non-steroidal anti-inflammatory drugs [non-steer-OYD-uhl an-tie-in-FLAM-uh-tor-ee or an-tee-in-FLAM-uh-tor-ee]

also called NSAIDs. Pain relievers and fever reducers in the family of aspirin, ibuprofen (Motrin®, Advil®), naproxen (Aleve®), and many others. Some studies have found that these drugs may lower the risk of colorectal cancer and adenomatous polyps. But the drugs can also irritate the stomach and cause bleeding and other side effects; some have been linked to higher risk of stroke and heart attack. See also colorectal cancer, polyp, familial adenomatous polyposis.

nuclear medicine

a branch of medicine that uses radioactive substances (radioisotopes) to diagnose and treat illnesses. See also radioisotope.

nuclear medicine scan

a method for finding diseases of internal organs such as the brain, liver, or bone. Small amounts of a radioactive substance (called an isotope) are put into the bloodstream. The isotope collects in certain organs and a special camera called a scintillation camera is used to make a picture of the organ and show areas of disease. See also radioisotope.

nucleus [new-klee-us]

the center of a cell where the deoxyribonucleic acid (DNA) is found and where it reproduces. Studying the size and shape of a cell’s nucleus under the microscope can help pathologists tell cancer cells from non-cancer cells. See also cell, deoxyribonucleic acid, pathologist.

nulliparous [nuh-lip-uh-rus]

never having given birth to a child.

nurse practitioner [nurs prak-tih-shun-er]

a registered nurse with a master’s or doctoral degree and special certification. Nurse practitioners diagnose and manage illness and disease, usually working closely with doctors.



a certain level of overweight; in general, a body mass index (BMI) greater than 30. BMI is figured out based on height and weight, but is not an absolute measure for overweight or obesity. Because it does not differentiate between fat and muscle, other tests must be done to know whether a person with a high BMI is actually obese.

occult [uh-kult or o-kult]

hidden or concealed. In cancer screening, can refer to small amounts of blood in stool that cannot be seen identified without special tests. See also fecal occult blood test and colorectal cancer screening.

occupational therapist [ok-you-PAY-shun-uhl]

a specially trained therapist who works with people who have disabilities to help them relearn how to perform daily activities. See also cancer care team.

off label

refers to the use of a drug to treat a condition other than that for which it was approved by the Food and Drug Administration (FDA).

omentum [o-men-tum]

a large fatty sheet in the abdomen (belly) that drapes like an apron over the stomach, intestines, and other organs.

oncogenes [on-kuh-jeenz]

mutated (changed) forms of genes that cause cells to grow and divide. Oncogenes are related to normal genes called proto-oncogenes that control normal cell growth. But oncogenes may undergo changes that activate them, resulting in cells growing out of control and becoming cancerous. See also genes, tumors. Compare to tumor suppressor genes.

oncologist [on-kahl-uh-jist]

a doctor with special training in the diagnosis and treatment of cancer. See also cancer care team.

oncology [on-kahl-o-jee]

the branch of medicine concerned with the diagnosis and treatment of cancer.

oncology clinical nurse specialist [on-kahl-o-jee]

a registered nurse with a master’s degree in oncology nursing who specializes in the care of cancer patients. Oncology nurse specialists may prepare and give treatments, monitor patients, prescribe and provide supportive care, and teach and counsel patients and their families. See also cancer care team.

oncology social worker [on-kahl-o-jee]

a person with a master’s degree in social work who is an expert in coordinating and providing non-medical care to patients. The oncology social worker counsels and assists people with cancer and their families, especially in dealing with the non-medical issues that can result from cancer, such as financial problems, housing (when treatments are given at a facility away from home), and child care. See also cancer care team.

oncoplastic surgery

newer techniques that combine oncology (cancer care) with plastic surgery.

one-step procedure

in breast cancer treatment, surgery done right after the biopsy (procedure to diagnose the cancer). The patient is given general anesthesia and does not know until waking up if the diagnosis was cancer or if extensive surgery (for instance mastectomy) was done. Once the only option in breast cancer, the one-step procedure is now rarely used, having been replaced by a two-step approach. See also anesthesia, biopsy, mastectomy, two-step procedure.

oophorectomy [oh-of-uh-rek-tuh-me]

surgery to remove the ovaries. See also ovary.

ophthalmologist [off-thuhl-MAHL-uh-jist]

a medical doctor who specializes in eye diseases.


refers to the mouth. For example, medicines that are taken orally are taken by mouth. Oral cancer is cancer of the mouth.

oral and maxillofacial surgeon [max-ill-o-FAY-shul]

a surgeon who specializes in operating on the mouth, jaw, and face.

oral contraceptives

birth control pills, which contain estrogen and/or a progesterone-like substance, known as progestin. See also estrogen, hormone, progesterone.

orchiectomy [or-key-ECK-tuh-me]

surgery to remove the testicles; also called castration. See also hormone therapy, testicles.

oropharynx [or-oh-FAIR-ingks]

the part of the throat below the soft palate and above the epiglottis, mostly behind the mouth. See also epiglottis, nasopharynx.

orthopedic surgeon [or-thuh-pee-dik]

a surgeon who specializes in diseases and injuries of the bones.

osteoporosis [os-tee-o-puh-RO-sis]

thinning of bone tissue, causing less bone mass and weaker bones, which is more common in older people. Osteoporosis can cause pain, deformity (especially of the spine), and broken bones. See also spine.

ostomy [os-tuh-me]

a general term meaning an opening, especially one made by surgery. See also colostomy, ileostomy, tracheostomy, urostomy.

ostomy nurse

see enterostomal therapist.

otolaryngologist [o-toe-lair-in-GOL-uh-jist]

also called a head and neck surgeon or an ENT (ear, nose, throat doctor); a doctor who specializes in diseases of the ear, nose, and throat.


a person being treated without staying in the hospital. Compare to inpatient. See also ambulatory.


the eggs that are released (usually one at a time) each month during a woman’s reproductive (fertile) years. The egg must be fertilized by a sperm to grow into a baby. A female is born with all the ova she will ever have. The singular of ova is ovum. See also sperm.

ovarian ablation

removal of the ovaries or inactivation of their hormones. See also ablation, ovary, hormone therapy.

ovary [o-vuh-ree]

reproductive organ in the female pelvis. Normally a woman has 2 ovaries. They contain the eggs (ova) that, when joined with sperm, can result in pregnancy. Ovaries are also the main source of estrogen, the main female sex hormone. See also estrogen, ova, sperm.

overflow incontinence

urine leak that happens when the bladder cannot be emptied. A person with overflow incontinence may need to get up often during the night to urinate, take a long time to urinate, and have a dribbling stream with little force. Overflow incontinence is usually caused by blockage or narrowing of the bladder outlet, either from cancer or scar tissue. Compare with stress incontinence, urge incontinence.



an important tumor suppressor gene that is not working properly in many cancers. The protein that this gene makes (also called p53) normally causes damaged cells to die. Mutations (changes) in this gene can be inherited (passed on from a parent) or they can happen during a person’s life. When these mutations are present, they can increase risk of many types of cancer. See also inherited disease, mutation, tumor suppressor genes.

Paget disease of the nipple [paa-jet]

a rare form of breast cancer that begins in the milk passages (ducts) and spreads to the skin of the nipple and areola. This affected skin may look crusted, scaly, red, or oozing. The prognosis (outlook) is generally better if these nipple changes are the only sign of breast disease and no lump can be felt. Named for the doctor who first identified it; also known as Paget’s disease. See also areola, duct, nipple

pain specialist

a doctor, nurse, or pharmacist who is an expert in pain control.

palliate [pal-ee-ate]

to relieve symptoms, such as pain, nausea, or fullness. See also palliative treatment.

palliative treatment or palliative care [pal-ee-uh-tiv]

treatment that relieves symptoms, such as pain, but is not expected to cure disease. Curative treatment can be used at the same time as palliative treatment, but the main purpose of palliative care is to improve the patient’s quality of life.

palpation [pal-pay-shun]

using the hands to examine. A palpable mass is one that can be felt.

pancolitis [pan-ko-LITE-us]

ulcerative colitis throughout the entire colon. See also colon, ulcerative colitis.

pancreas [pan-kree-us]

an organ that lies behind the stomach and contains 2 different types of gland cells. One type makes enzymes which are released into the intestines to help digest food. The other type makes insulin and glucagon, which help regulate blood sugar. See also enzyme, glandular cells.

pancreatectomy [pan-cree-uh-TEK-tuh-me]

surgery to remove the pancreas. See also pancreas.


see prostatic acid phosphatase. (Not the same as Pap test, the cancer screening method for women. For that, see Pap test.)

Pap test, also called a Pap smear

a test in which cells are scraped from a woman’s cervix and looked at under a microscope to see if abnormal cells are present. Human papillomavirus (HPV) testing is often done at the same time, and a pelvic examination is usually done as well, but these are not part of the Pap test. See also cervix, human papillomavirus, pelvic examination.

papillary [PAP-uh-lair-ee]

cancer cells that are arranged in tiny, finger-like projections when looked at under a microscope. This is a common feature of some tumors of the ovaries, uterus, thyroid gland, and other organs. See also histology, ovary, pathologist, thyroid, uterus.

papilloma [PAP-uh-lo-muh]

benign (not cancer) growth.

parafollicular [pair-uh-fah-LICK-yuh-ler]

having to do with a follicle. In cancer, the term can be used to describe the C cells on the thyroid (parafollicular cells). See also follicle, follicular.

partial mastectomy

see mastectomy.

Partin tables

in prostate cancer, a tool that uses the prostate-specific antigen (PSA), Gleason score, and stage that are obtained before surgery to predict the odds that the cancer has spread outside the prostate. See also Gleason score, prostate, prostate-specific antigen, staging.

patella or kneecap [puh-tel-uh]

the small, flat, movable bone that forms the front of the knee and protects the knee joint.

pathologic stage

see staging.

pathologist [path-all-uh-jist]

a doctor who specializes in diagnosing and classifying diseases in the lab by testing and looking at cells under a microscope. The pathologist determines whether a tumor is benign (not cancer) or cancer, and if cancer, the exact cell type and grade.

pectoral muscles

muscles attached to the front of the chest wall and upper arms. The larger one is called pectoralis major, and the smaller one is called pectoralis minor. Because these muscles are next to the breast, breast cancer may spread to them, although this rarely happens.

pediatric oncologist [pee-dee-at-trick on-kahl-uh-jist]

a doctor who specializes in cancers of children. See also cancer care team.

pediatrician [pee-dee-uh-TRISH-un]

a doctor who specializes in the care of children.

pelvic examination [pell-vick ex-am-in-A-shun]

an exam of a woman’s uterus and other pelvic organs. It is used to help find cancers of the reproductive organs. The doctor will look at external structures and palpate (feel) the internal organs such as the ovaries and uterus. See also cervix, ovary, pelvis, uterus.

pelvic exenteration [ex-en-ter-A-shun]

surgery to remove the organs in the pelvis. See also pelvis.

pelvic lymph node dissection [pell-vick limf node diss-eck-shun]

removal of the lymph nodes in the pelvis. See also lymph node, pelvic nodes, pelvis.

pelvic nodes

pelvic lymph nodes; the lymph nodes to which prostate cancer is most likely to spread. These nodes are often removed and checked for cancer as part of surgery to remove prostate and other cancers in the pelvis. See also lymph node, pelvic lymph node dissection, pelvis, prostate.

pelvis [pell-vis]

the part of the skeleton that forms a ring or basin of bones below the belly (abdomen). Pelvis may also refer to the general area of the body between the hip bones, below the abdomen. The pelvis contains the bladder, reproductive organs, and the rectum. See also bladder, rectum.

penile implant [PE-nile im-plant]

artificial device placed in the penis during surgery to help a man have erections. See also erectile dysfunction.

penis [pe-nis]

the male sex organ.

percent-free PSA [or fPSA]

a test that shows how much prostate-specific antigen (PSA) circulates unattached to blood proteins (alone) in the blood. The percent-free PSA (fPSA) is the ratio of how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not. A low fPSA may suggest the need for a biopsy. Also known as free-PSA ratio. See also biopsy, complexed PSA, prostate, prostate-specific antigen.

perforation [per-fuh-RAY-shun]

a hole in the wall of a hollow organ, like the bladder or lung.

perineal prostatectomy [pair-uh-NEE-ul pros-tuh-TECK-tuh-me]

an operation in which the prostate is removed through an incision (cut) in the skin between the scrotum and anus. See also anus, perineum, prostate, scrotum.

perineum [pair-uh-NEE-um]

the area between the anus and the scrotum or the vagina. This is called the perineal area. See also anus, scrotum, vagina.

perineural invasion [pair-uh-NOO-rul]

invasion of cancer cells into areas around nerves of the prostate gland. This is sometimes reported by pathologists looking at the prostate after it has been surgically removed, but it is not thought to affect a man’s prognosis (survival outlook). See also pathologist, prostate.

peripheral blood stem cell transplant

see hematopoietic stem cell transplant.

peripheral zone [per-if-er-uhl zon]

the outer part, near the outer edges. In the prostate, for instance, it is this area where most prostate cancers occur. See also prostate.

peritoneum [pear-i-tuh-NEE-um]

membrane that lines the abdomen (belly) and covers most of its organs. Peritoneal cavity refers to the area enclosed by the peritoneum.

permanent brachytherapy

see low-dose rate brachytherapy.

permanent section

biopsy tissue that has been prepared to be looked at under a microscope. The tissue is soaked in formaldehyde, processed in various chemicals, enclosed in a block of wax, sliced very thin, attached to a microscope slide, and stained. This process usually takes 1 to 2 days. It allows a clear view of the cells in the sample so that the pathologist can see whether or not cancer is present. Compare with frozen section. See also biopsy, pathologist.

PET scan

see positron emission tomography.

pharynx [fair-ingks]

the throat; the tube that connects the mouth and nasal passages with the swallowing tube (esophagus) and windpipe (trachea). It extends from above the soft palate, behind the mouth, down to the epiglottis. See also epiglottis, oropharynx, nasopharynx.

pheresis [fuh-ree-sis]

see apheresis.

phosphodiesterase inhibitors [fos-foe-die-ES-ter-ace in-hib-it-urs]

also called PDE5 inhibitors. Drugs, such as sildenafil (Viagra®), vardenafil (Levitra®), and tadalafil (Cialis®), that can help men get an erection. Not all forms of impotence respond to these drugs. See also impotence.

photocoagulation or photoablation [foe-toe-ko-ag-yu-LAY-shun or foe-toe-uh-blay-shun]

use of a laser beam to heat up and kill cancer cells. Most often used to relieve blockages rather than to cure cancers. See also ablation.

photodynamic therapy [foe-toe-die-NAM-ick]

also called PDT. A treatment sometimes used for cancers of the skin, esophagus (swallowing tube), lung, or bladder. PDT begins with the injection of a non-toxic chemical into the blood. This chemical is allowed to collect in the tumor for a couple of hours to a couple of days, depending on the chemical. A special type of laser light is then focused on the cancer. This light causes the chemical to change so that it can kill cancer cells. The advantage of PDT is that it can kill cancer cells with very little harm to normal cells. The downside is that it can only be used in areas that can be reached with light.

photon beam radiation therapy [foe-ton]

standard type of radiation used for external beam radiation treatments. See also conformal radiation therapy, external beam radiation therapy.

phyllodes tumor [fie-loads too-mer]

also called phylloides tumor or cystosarcoma phyllodes. A rare breast tumor, usually not cancer (benign), which grows quickly and can become quite large.

physical therapist

a health professional who uses exercises and other methods to restore or maintain the body’s strength, mobility, and function.

physiologic [fiz-ee-o-LA-jick]

pertaining to the processes of the body or its systems. May also be used to describe a particular body function or organ as normal.

phytochemical [fie-toe-KEM-ih-kul]

substance produced by plants that may produce health benefits when eaten or ingested; for example, antioxidants. See also antioxidants.


see prostatic intraepithelial neoplasia.

pituitary [pit-too-it-air-ee]

small gland underneath the brain which controls other endocrine glands in the body. Also called the master gland. See also endocrine glands.

placebo [pluh-see-bo]

an inert, inactive substance or sham procedure that may be used in studies (clinical trials) to compare the effects of a given treatment with no treatment. The pill form is commonly called a “sugar pill.” Placebo can mean a treatment, injection, or even something that looks like real surgery that is used when studying a treatment that is not given by mouth. Placeboes are not used in studies where a proven treatment is available; instead, the new treatment is tested against the proven one.

plastic or reconstructive surgeon [re-kon-STRUCK-tiv]

a surgeon specializing in restoring appearance or in rebuilding or replacing removed or injured body parts.

platelet [plate-let]

a type of blood cell that helps stop bleeding by plugging up holes in blood vessels after an injury. Chemotherapy can cause a drop in the platelet count, a condition called thrombocytopenia that carries a risk of excessive bleeding. See also chemotherapy.

pleura [plur-uh]

the membranes around the lungs and lining the chest cavity.

pleurodesis [plu-rah-dis-sis or plur-o-DEE-sis]

injection of an agent between the layers of the pleura that causes them to fuse to seal off leaks. This procedure helps prevent fluid or air from building up in the pleural cavity, the area between the pleura. See also pleura.

ploidy [ploy-dee]

number of sets of chromosomes contained in a cell. Ploidy is a marker that helps predict how quickly a cancer is likely to spread. Cancers with 23 pairs of chromosomes (the same as normal cells) are called diploid (dip-loyd) and those with either more or less than that amount are aneuploid (an-you-ployd). See also chromosome, deoxyribonucleic acid.

pneumonectomy [new-muh-NECK-tuh-me]

surgery to remove a lung. See also lobectomy.

polycythemia vera [pah-lee-sy-THEME-e-uh vair-uh]

a chronic blood disorder in which the bone marrow makes too many red blood cells, white blood cells, and platelets. This leads to a higher concentration of hemoglobin with larger amounts of red blood cells, which is the main feature of this disease. But with time, the high platelet count may become more of a problem and patients can suffer from problems with blood clots because of this and their “thickened” blood. Often, the spleen is enlarged. Over time, the bone marrow is replaced by fibrous tissue (myelofibrosis). Although it is not a true cancer, it often turns into acute myelogenous leukemia (AML) after many years. See also bone marrow, leukemia, platelet, red blood cells, spleen, white blood cells.

polyp [pah-lip]

a growth from a mucous membrane commonly found in organs such as the rectum, the uterus, and the nose. Polyps may be non-cancerous (benign) or cancerous (malignant). See also adenomatous polyp, hyperplastic polyp, inflammatory polyp, mucous membrane, rectum, uterus.

polypectomy [pah-lup-ECK-tuh-me]

surgery or procedure to remove a polyp. See also polyp.

portography [por-tahg-ruh-fee]

a procedure that uses computed tomography (CT) and a dye injected into the portal vein of the liver. It takes cross-sectional x-rays of the veins to find cancer that may have spread from the colon or rectum. See also colon, computed tomography, rectum, x-ray.

positive margin

see surgical margin.

positron emission tomography [pahs-uh-trahn ee-mish-uhn tom-ahg-ruh-fee]

also called a PET scan. An imaging method that creates a picture of the body (or of biochemical events) after the injection of a very low dose of a radioactive form of a substance such as glucose (sugar). The scan computes the rate at which the tumor is using the sugar. All cells use sugar, but high-grade tumors use more sugar than normal and low-grade tumors use less than high-grade ones. PET scans may be used to find tumors or see how well a tumor is responding to treatment. See also grade, imaging studies, nuclear medicine, radioisotope.

posterior [post-eer-ee-uhr]

the back or near the back of an organ or the body.

poultice [pole-tiss]

soft paste or thick liquid that is usually heated, applied to a cloth, and placed over an inflamed or painful area. Herbs, leaves, or foods are commonly used for this in folk medicine and home remedies.


also called pre-malignant. Changes in cells that may, but do not always, become cancer.


see pre-cancerous.

predisposition [pre-dis-puh-ZISH-un]

susceptibility to a disease that can be triggered under certain conditions. For example, some women have a family history of breast cancer and are more likely (but not necessarily destined) to develop breast cancer.

prevalence [preh-vul-uns]

a measure of the proportion of people in a population with a particular disease at a given time. Compare to incidence.


the reduction of cancer risk by eliminating or reducing contact with things known to cause cancer, by changing conditions that contribute to cancer (such as obesity or lack of exercise), or by using medicines that interfere with cancer development. Lifestyle changes, such as quitting smoking, for example, reduces the number of people who will get lung and other cancers.

primary care physician

the doctor a person would normally see first when a problem arises. A primary care doctor could be a general practitioner, a family practice doctor, a gynecologist, a pediatrician, or an internal medicine doctor (an internist).

primary site

the place where cancer begins. Cancer is usually named after the organ in which it first starts. For example, cancer that starts in the breast is always breast cancer, even if it spreads (metastasizes) to other organs such as bones or lungs. See also metastasize, metastasis.

primary treatment or primary therapy

the first, and usually the most important, treatment.

progesterone [pro-jes-ter-own]

a female sex hormone released by the ovaries during every menstrual cycle to prepare the uterus (womb) for pregnancy and the breasts for milk production (lactation). See also hormone, ovary.

progesterone receptor assay

a lab test done on a sample (biopsy) of breast cancer that shows whether the cancer depends on progesterone for growth. Progesterone and estrogen receptor tests provide information to help decide whether the patient would be helped by medicines that block these hormones. See also biopsy, estrogen, estrogen receptor assay, progesterone.

prognosis [prog-no-sis]

a prediction of the course of disease; the outlook for the chances of survival.


spreading or growing disease, with or without treatment.


a hormone released from the pituitary gland that prompts the breasts to produce milk. See also hormone, pituitary.

proliferative [pro-lih-fer-uh-tiv]

rapid or excessive growth or multiplication of cells.

prophylactic mastectomy [pro-fuh-LACK-tik]

see mastectomy.

prostaglandin E1 [pros-tuh-GLAN-din]

a substance found naturally in the body that can be used to produce erections. It can be injected into the base of the penis or put into the urethra as a suppository or pellet. See also urethra.

ProstaScintTM scan [pros-tuh-sent]

an imaging study that uses low-level radioactive material to find prostate cancer that has spread beyond the prostate. The radioactive material is attached to an antibody made in a lab to recognize and stick to prostate-specific membrane antigen (PSMA), a substance found only in normal and cancerous prostate cells. This test detects spread of prostate cancer to bone, lymph nodes, and other organs, and can clearly distinguish prostate cancer from other cancers and non-cancer disorders. The ProstaScint scan is most commonly used to look for cancer if the prostate-specific antigen (PSA) level is still high after treatment. See also antibody, lymph node, prostate, prostate-specific antigen, radioisotope.

prostate [pros-tate; note that there is no “r” in the second syllable]

a gland found only in men. It is just below the bladder and in front of the rectum. The prostate makes a fluid that is part of semen. The tube that carries urine, the urethra, runs through the prostate. See also bladder, rectum, semen.

prostate-specific antigen

also called PSA. A protein made by the prostate gland. Levels of PSA in the blood often go up in men with prostate cancer as well as other conditions. The PSA test is sometimes used to help screen for prostate cancer, but it cannot predict which prostate cancers will grow and cause problems later. It is also used to check the results of treatment. See also prostate.

prostatectomy [pros-tuh-TECK-tuh-me]

surgical removal of all or part of the prostate gland. See also prostate.

prostatic acid phosphatase [pros-tat-ick a-sid fos-fuh-tace]

also called PAP. A blood test, like the prostate-specific antigen (PSA) test, that may be done when looking for evidence of prostate cancer. Unlike the PSA test, the PAP test is not useful for prostate cancer screening. (This not the same as the Pap screening test for cervical cancer; for that, see Pap test.) See also prostate, prostate-specific antigen, screening.

prostatic intraepithelial neoplasia [pros-tat-ick in-trah-ep-ith-EE-lee-uhl hi-per-play-zhuh]

also called PIN. A condition in which there are changes in how the prostate gland cells look under the microscope. The changes are classified as low-grade, meaning that the cells look almost normal, or high-grade, meaning that they look more abnormal. The condition is not cancer, but it may lead to the development of cancer. High-grade PIN is more likely to become cancer than low-grade PIN. See also prostate, atypia.

prostatic urethra [pros-tat-ick yoo-ree-thruh]

the part of the urethra that runs through the prostate. See also prostate, urethra.

prostatitis [pros-tuh-TIE-tus]

inflammation of the prostate. Prostatitis is not cancer, although it can produce swelling and cause trouble passing urine. See also prostate.

prosthesis [pros-thee-sis]

an artificial replacement part of the body, such as a breast prosthesis. A prosthesis may be implanted surgically inside the body or worn outside the body.

protein [pro-teen]

a large molecule made up of a chain of smaller units called amino acids. Proteins serve many vital functions inside and outside of the body’s cells.

protocol [pro-tuh-call]

a formal outline or plan, such as a description of what treatments a patient will get and exactly when each should be given. See also regimen.

proton [pro-tahn]

a radioactive particle used in some forms of radiation therapy. See also conformal proton beam radiation therapy, radiation therapy.

proton beam therapy

see conformal proton beam therapy.


see prostate-specific antigen.

PSA density [PSAD]

PSAD is determined by dividing the prostate-specific antigen (PSA) level by the prostate volume (its size as measured by transrectal ultrasound). A higher PSAD indicates a greater likelihood of cancer. See also prostate, prostate-specific antigen, transrectal ultrasound.

PSA doubling time [PSADT]

the length of time it takes for the prostate-specific antigen (PSA) level in the blood to double. This is sometimes useful in determining if prostate cancer is present or has come back (recurred). See also prostate, prostate-specific antigen.

PSA velocity [PSAV]

a measurement of how quickly the prostate-specific antigen (PSA) level rises over a period of time. A higher PSAV was once thought to suggest greater chance of prostate cancer being present, but that may not be true. See also prostate, prostate-specific antigen.

psychiatrist [sy-ky-uh-trist]

a medical doctor specializing in mental health and behavioral disorders. Psychiatrists can prescribe medicines and offer other types of mental health therapy.

psychologist [sy-koll-uh-jist]

a health professional who assesses a person’s mental and emotional status and provides counseling.

psychosocial [sy-ko-SO-shul]

the psychological and/or social aspects of health, disease, treatment, and/or rehabilitation.


a gene that normally helps control cell growth. Inherited changes in this gene cause Cowden syndrome, a rare disorder in which people are at higher risk for both non-cancer and cancer breast tumors. It is also linked to growths in the digestive tract, thyroid, uterus, and ovaries. See also gastrointestinal tract, gene, inherited disease, mutation, ovary, thyroid, uterus.

pubic bone [pew-bick]

also called pubis or pubic arch. Arch of bone at the center base of the pelvis, where the 2 sides join in the front. See also pelvis.

pulmonologist [pull-muh-NAHL-uh-jist]

a doctor who has specialized experience and knowledge in the diagnosis and treatment of lung conditions and diseases.


quality of life

overall enjoyment of life, which includes a person’s sense of well-being and ability to do the things that are important to him or her.



energy in a wide variety of forms that makes up the electromagnetic spectrum. It ranges from light and heat to radio waves, microwaves, and x-rays. In medicine, the 2 main types are ionizing and non-ionizing radiation. The high-energy rays that are used for x-rays, and in higher doses for cancer treatment, are called ionizing radiation. Ionizing radiation has enough energy to remove electrons from atoms. This type of radiation can be produced by medical devices, but also comes from natural sources such as radon gas (in the ground) and outer space. See also radiation dose, radiation therapy, x-ray.

radiation dose

the amount of radiation an object (such as human tissue) receives. Several units are used to describe radiation doses, as listed below.
  • rad (acronym for radiation absorbed dose) -- a basic unit of the amount of radiation transferred to an object. This measurement does not take into account the type of radiation, which can influence the effect on different body tissues. The rad has largely been replaced by the gray measurement scale (see next).
  • gray (abbreviated Gy) -- the newer, international unit of measurement of radiation transfer. One gray equals 100 rads, and a centigray is 1/100th of a gray. So, one rad equals one centigray (cGy). 1/1000 of a gray is called a milligray (mGy).
  • rem (acronym for roentgen equivalent man) -- a basic unit of radiation exposure which is based on both the dose and the type of radiation. Because of this, it is more commonly used to describe radiation exposure in humans than is the rad. Often reported in units of millirem (mrem), which is 1/1000 of a rem. The rem is sometimes replaced by the sievert (see next).
  • sievert (see-vert) -- abbreviated Sv. A newer, international unit of measurement of radiation exposure that can measure human radiation exposure. One sievert equals 100 rem. Often reported in millisieverts (mSv), which are thousandths of a sievert (or about 1/10 of a rem).
  • radiation oncologist [ray-dee-A-shun on-kahl-uh-jist]

    a doctor who specializes in using radiation to treat cancer. See also cancer care team.

    radiation proctitis [ray-dee-A-shun prok-tie-tis]

    a possible side effect of radiation therapy to the pelvic area, involving inflammation of the rectum and anus. Problems can include pain, frequent bowel movements, bowel urgency, bleeding, chronic burning, or rectal leakage. See also anus, pelvis, radiation therapy, rectum.

    radiation therapist [ray-dee-A-shun ther-uh-pist]

    a person with special training to use the equipment that delivers radiation therapy.

    radiation therapy [ray-dee-A-shun ther-uh-pee]

    treatment with high-energy rays (ionizing energy, such as x-rays) to kill cancer cells and shrink tumors. The radiation may come from outside the body (external radiation) or from radioactive materials placed in the tumor (brachytherapy or internal radiation). Radiation therapy may be used to shrink the cancer before surgery, to kill any remaining cancer cells after surgery, or as the main treatment. It may also be used as palliative (non-curative) treatment for advanced cancer. See also brachytherapy, external beam radiation therapy, intensity modulated radiation therapy, palliative treatment, radiation dose, three-dimensional conformal radiation therapy, x-ray.

    radical perineal prostatectomy [rad-ick-uhl pair-uh-NEE-ul pros-tuh-TECK-tuh-me]

    surgery to remove the prostate through the perineum (skin behind the testicles). It is used less often, in part because this approach makes it harder for the surgeon to spare the nerves that control erections. See also neurovascular bundles, nerve-sparing prostatectomy, perineum, prostate, radical prostatectomy, retropubic prostatectomy, testicles.

    radical prostatectomy [rad-ick-uhl pros-tuh-TECK-tuh-me]

    surgery to remove the entire prostate gland, the seminal vesicles, and nearby tissue. See also prostate, seminal vesicles.

    radioactive implant [ray-dee-o-ACT-iv im-plant]

    a source of ionizing radiation that is placed in or around a tumor to kill the cancer cells. See also brachytherapy, radiation.

    radiocontrast dye [ray-dee-o-CON-trast]

    also called dye, contrast dye, radiocontrast medium. Any material used in imaging studies such as x-rays, MRIs, and CT scans to help outline the body parts being examined. These may be injected or ingested (drunk). See also imaging studies.

    radiofrequency ablation [ray-dee-oh-free-kwin-see uh-blay-shun]

    also called RFA. Treatment that uses high-energy radio waves to heat and destroy abnormal tissues. A thin, needle-like probe is guided into the tumor by ultrasound or computed tomography (CT) scan. The probe releases a high-frequency current that heats and kills cancer cells. RFA is sometimes used to treat tumors in the liver, and is being studied for use in other areas of the body. See also computed tomography scan, ultrasound.

    radioisotope [ray-dee-oh-EYE-suh-tope]

    a type of atom that is unstable and prone to break up (decay). Decay releases small fragments of atoms and radiation energy. Exposure to certain radioisotopes can cause cancer. But radioisotopes are also used to find and treat cancer. In certain imaging tests, for example, radioisotopes are injected into the body where they then collect in areas where the disease is active, showing up as brighter areas on the pictures. See also imaging studies, nuclear medicine, radiation.

    radiologic technologist [ray-dee-uh-LAH-jick teck-nah-luh-jist]

    a health professional (not a doctor) trained to position patients for x-rays, take the images, and then develop and check the images for quality. The films taken by the technologist are sent to a radiologist to be read. See also radiologist, x-ray.

    radiologist [ray-dee-AH-luh-jist]

    a doctor with special training in diagnosis of diseases by interpreting or reading x-rays and other types of diagnostic imaging studies; for example, CT and MRI scans. See also imaging studies, x-ray.

    radionuclide bone scan [ray-dee-oh-NOO-klide]

    see bone scan.

    radiopharmaceuticals [ray-dee-oh-farm-uh-SUIT-ih-kulz]

    a group of drugs that include radioactive elements or radioisotopes, such as strontium-89 or samarium-153, which are given into a vein (intravenously or IV) to treat bone pain related to cancer that has spread to the bones. See also radioisotope, strontium-89.


    See radiation therapy.

    radius [ray-dee-us]

    in the human body, there are 2 bones in the forearm that go from the elbow to the wrist. The bone on the thumb side is the radius. See also ulna.

    randomized or randomization

    a process in clinical trials that uses chance to assign participants to different groups that compare treatments. Randomization means that each person has an equal chance of being in the treatment and control (comparison) groups. This helps reduce bias in the results that might happen, if, for example, the healthiest people all were assigned to a particular treatment group. See also control group, clinical trials.


    a second surgery to remove remaining cancer. This may be done if cancer cells were found at the edge of surgically removed tissue. See also surgical margin.

    rectal surgery

    main treatment for rectal cancer. Radiation and chemotherapy may be given before or after surgery. See also adjuvant therapy, chemotherapy, neoadjuvant therapy, radiation, rectum.


    the last part of the large intestine between the sigmoid colon and the anus. See also anus, colon, sigmoid colon.


    the return of cancer after treatment. Local recurrence means that the cancer has come back at the same place as the original cancer (primary site). Regional recurrence means that the cancer has come back after treatment in the lymph nodes near the primary site. Distant recurrence is when cancer spreads (metastasizes) after treatment to distant organs or tissues (such as the lungs, liver, bone marrow, or brain). See also lymph node, metastasis, metastasize, primary site.

    red blood cells [RBCs]

    blood cells that contain hemoglobin, the substance that carries oxygen to all of the cells of the body. These cells are made in the bone marrow. Low red blood cell counts, a condition called anemia, are a common side effect of many cancer treatments. See also anemia, bone marrow.

    reduced-intensity conditioning

    doses of radiation or chemotherapy given before an allogeneic stem cell transplant, in which lower doses are used to leave some of the patient’s bone marrow cells while the new marrow engrafts. See also bone marrow, chemotherapy, conditioning treatment, hematopoietic stem cell transplant, mini-transplant, radiation.

    reduction mammoplasty

    see mammoplasty.

    refractory [re-frack-tuh-re]

    no longer responsive to a certain treatment. See also drug resistance.

    regimen [reh-juh-men]

    a strict, regulated plan (such as diet, exercise, or a medicine schedule) designed to reach certain goals. In cancer treatment, a treatment plan which may include different medicines given on a certain schedule, as well as other methods such as radiation treatments. See also protocol.

    regional involvement or regional spread

    the spread of cancer from its primary (original) site to nearby areas such as lymph nodes, but not to distant sites. See also lymph node, metastasis, primary site.

    regression [re-gresh-un]

    decrease in the size of the tumor or the extent of the cancer.

    rehabilitation [re-huh-bill-ih-TAY-shun]

    activities to help a person adjust, heal, and return to a full, productive life after injury or illness. This may involve physical restoration (such as the use of prostheses, exercises, and physical therapy), counseling, and emotional support. See also prosthesis, physical therapist, occupational therapist.

    relapse [re-laps]

    reappearance of cancer or other disease after a disease-free period. See also recurrence.


    see radiation dose.

    remission [re-MISH-un]

    complete or partial disappearance of the signs and symptoms of cancer in response to treatment; the period during which a disease is under control. A remission may not be a cure.

    replicate [REP-lih-kate]

    reproduce exact copies.

    rescue treatment

    in cancer care, procedures or treatments such as bone marrow transplant that “rescue” a patient’s immune system and blood-forming organs by stopping the actions of high-dose chemotherapy. See also bone marrow transplant, chemotherapy, immune system.

    resection [re-sek-shun]

    surgery to remove part or all of an organ or other structure.

    resectoscope [re-SEK-tuh-scope]

    instrument used in transurethral resection of the prostate (TURP), allowing the surgeon to look at the prostatic urethra and nearby prostate tissue. See also prostate, prostatic urethra, transurethral resection of the prostate.

    respiratory therapist [RES-per-uh-tor-ee ther-uh-pist]

    under the direction of a doctor, the respiratory therapist gives breathing treatments and helps manage patients on breathing machines called ventilators or respirators.

    respite care [res-pit]

    the short-term care of a sick person to provide a break (respite) to the regular caregiver(s). Respite care may be given in a nursing home, hospital, or even in the home by substitute care providers.


    outcome after treatment, or the reaction to a drug or any other therapy.


    see urinary retention.

    retinoids [ret-n-oyds]

    vitamin A and synthetic (man-made) compounds similar to vitamin A.

    retrograde ejaculation [ret-tro-grade e-jack-you-LAY-shun]

    a condition, often happening after prostate surgery or radiation in which orgasm causes semen to enter the bladder, rather than leaving the body through the penis. Also known as a dry orgasm. See also abdominoperineal resection, bladder, prostate, radiation, radical prostatectomy, semen, transurethral resection of the prostate.

    retropubic [ret-tro-PEW-bick]

    behind the pubic bone but in front of the bladder. In prostate cancer, a surgical approach to the prostate through an incision (cut) in the lower abdomen (belly) is called a retropubic prostatectomy. See also bladder, prostate, pubic bone.

    reverse transcription polymerase chain reaction [re-verse tran-scrip-shun puh-lim-er-ace]

    also called RT-PCR. A very sensitive test for finding cancer-related genetic changes (mutations) in blood, bone marrow, lymph nodes, or other tissue. RT-PCR uses chemical analysis of the ribonucleic acid or RNA (a substance related to deoxyribonucleic acid or DNA) from genes affected by the translocation (in which DNA from one chromosome breaks off and gets attached to a different chromosome). See also bone marrow, chromosome, deoxyribonucleic acid, lymph node, mutation, ribonucleic acid, translocation.


    one of a series of 12 pairs of curved bones, some of which connect to the sternum and spine to form the rib cage. The ribs enclose the chest and help protect the heart, lungs, and other organs.

    ribonucleic acid or RNA [ri-bo-noo-KLEE-ick a-sid]

    a molecule found in all cells that stores and carries genetic messages within the cell. See also deoxyribonucleic acid, messenger RNA.

    risk factor

    anything that is related to a person’s chance of getting a disease such as cancer. Some risk factors have a direct role in causing cancer, but in other cases the risk may be due to something else that goes along with the risk factor. For example, older age is linked to higher risk of many types of cancers, but the actual cause appears to be gene mutation (change), which is more likely to occur with age. Different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer; smoking is a risk factor for lung, mouth, throat, and other cancers. Some risk factors, such as smoking, can be controlled. Others, like a person’s age, can’t be changed. See also gene, mutation.


    see ribonucleic acid.

    RT-PCR test

    see reverse transcription polymerase chain reaction.


    s-phase fraction

    the percentage of cells that are replicating (making a copy of) their deoxyribonucleic acid (DNA). DNA replication usually means that a cell is getting ready to split into 2 new cells. A low s-phase fraction is a sign that a tumor is slow-growing; a high s-phase fraction shows that the cells are dividing rapidly and the tumor is growing quickly. See also deoxyribonucleic acid.

    saline [say-lean]

    saltwater solution.

    sarcoma [sar-ko-muh]

    a cancer that starts in connective tissue, such as cartilage, fat, muscle, or bone.


    a study using either x-rays or radioisotopes to make images of internal body organs. See also bone scan, brain scan, computed tomography scan, imaging studies, magnetic resonance imaging, nuclear medicine scan, radioisotope, x-ray.

    scintillation camera [sin-till-LAY-shun]

    device used in nuclear medicine scans to detect radioactivity and make pictures that help diagnose cancer and other diseases. See also nuclear medicine, nuclear medicine scan.

    scintimammography [sin-ti-mam-AHG-gruh-fee]

    an imaging study in which a radioactive tracer is put into a vein to find breast cancer cells. The tracer attaches to breast cancer cells. It is a newer technique that may help evaluate women with abnormal mammograms, and is still being studied as doctors try to improve its usefulness. See also imaging studies, mammogram. radioisotope.


    the search for disease, such as cancer, in people who do not have any symptoms. For example, screening tests for colon cancer include colonoscopy and the fecal occult blood test. Some of the same tests used for screening may also be used as diagnostic tests, which look for cancer in a person after there is some sign of a problem. For instance, a colonoscopy would be a diagnostic test if it was used in a person who had blood in the stool or symptoms of a blockage. See also colon, colonoscopy, fecal occult blood test.


    the pouch of skin that holds the testicles. See also testicles.

    secondary tumor

    a tumor that forms as a result of spread (metastasis) of cancer from the place where it started (the primary site). See also metastasis, primary site.

    sedation [suh-day-shun]

    to make sleepy, calm, or relaxed. Drugs to cause sedation are often used along with medicines to numb an area for a procedure or certain types of surgery. See also anesthesia.

    segmental resection [seg-men-tuhl re-sek-shun]

    surgery to remove part of an organ. With colon cancer, for instance, the cancer and a length of normal colon on either side of the cancer, as well as the nearby lymph nodes are removed. The remaining sections of the colon are then reattached. See also colon, lymph node.

    selective estrogen receptor modulator [SERM]

    an estrogen-like substance that has some, but not all, of the actions of estrogen. For example, raloxifene is classified as a SERM because it (like estrogen) prevents bone loss and lowers serum cholesterol but unlike estrogen, does not stimulate the uterus to grow a lining. Tamoxifen and aromatase inhibitors are also SERMs. See also aromatase inhibitors, estrogen, uterus.

    semen [see-muhn]

    fluid released during male orgasm that contains sperm and seminal fluid. See also ejaculate, sperm.

    seminal vesicles [sim-uh-nul ves-ih-kuls]

    glands at the base of the bladder and next to the prostate that release fluid into the semen during orgasm. Cancer that spreads beyond the prostate gland may invade the seminal vesicles. See also bladder, prostate, semen.

    sentinel lymph node biopsy [sen-tin-uhl]

    sometimes abbreviated SNLB. A procedure that is used instead of routine lymph node dissection (removal) for some cancer types, Blue dye and/or a radioisotope is injected into the tumor at the time of surgery and the first (sentinel) node that picks up the dye is removed and biopsied. If the node does not contain cancer, fewer nodes are removed. See also biopsy, lymph node, lymph node dissection, radioisotope.


    a non-cancerous lump or swelling that is caused by a build-up of clear fluid.

    sex therapist

    a mental health professional such as a licensed psychiatrist, social worker, clinical nurse specialist, nurse practitioner, or psychologist with special training in counseling people about sexual changes, problems, and communication (for example, after treatment for cancer).

    sextant biopsy [sex-tunt by-op-see]

    a biopsy of the prostate in which 6 core biopsy samples are taken, one each from the top, middle, and bottom of each side of the prostate. In most cases, doctors now take 12 or more core needle samples of the prostate for more complete sampling. See also biopsy, core needle biopsy, prostate.

    side effects

    unwanted effects of treatment such as hair loss caused by chemotherapy, and fatigue (extreme tiredness) caused by radiation therapy. See also chemotherapy, radiation therapy.

    sievert or Sv

    see radiation dose.

    sigmoid colon [sig-moyd ko-lun]

    the fourth section of the colon. The sigmoid colon attaches to the rectum, which in turn connects to the anus, the opening where waste matter passes out of the body. See also anus, ascending colon, colon, descending colon, transverse colon, rectum.

    sigmoidoscope [sig-MOYD-uh-scope]

    a thin, flexible, hollow, lighted tube about the thickness of a finger. It is inserted through the rectum up into the lower part of the colon. This allows the doctor to look at the inside of the rectum and the lower part of the colon for cancer or for polyps (small growths that can become cancer). The sigmoidoscope is connected to a camera and TV monitor so the doctor can look closely at the inside of the colon. See also colon, polyp, rectum, sigmoid colon, sigmoidoscopy.

    sigmoidoscopy [sig-moid-AH-skuh-pee]

    a procedure in which a doctor can look into the rectum and the descending portion of the colon for polyps or other abnormalities. See also colorectal cancer screening, descending colon, rectum, sigmoid colon, sigmoidoscope, polyp.


    a physical change you can see. Compare to symptom.


    a process involving special x-ray pictures that are used to plan radiation treatment so that the area to be treated is precisely located and marked for treatment. See also external beam radiation therapy, x-ray.


    see spectral karyotyping.

    small cell lung cancer

    one of the 2 main types of lung cancer classified based on how the cells look under the microscope. Small cell lung cancer tends to grow and spread faster than non-small- cell lung cancer. Compare to non-small-cell lung cancer.

    small intestine

    the longest section of the intestinal tube. It breaks down food and absorbs most of the nutrients. The small intestine leads into the large intestine. See also large intestine, gastrointestinal tract.

    social worker

    a health professional who helps people find community resources and provides counseling and guidance to help with issues like insurance coverage and nursing home placement. See also cancer care team.

    solar keratosis

    see actinic keratosis.

    somatic mutation [so-mat-ick mew-tay-shun]

    a change in deoxyribonucleic acid (DNA) that starts in one cell of the body at any time of life after an embryo is formed. All the cells that arise from that cell will typically have the same mutation, which in some cases can lead to cancer. This kind of mutation is different from inherited mutations, which are present at birth and in all the cells of the body. Somatic mutations are not passed on to children. Compare to inherited disease. See also deoxyribonucleic acid, mutation.

    spectral karyotyping [speck-truhl KAIR-ee-o-type-ing]

    abbreviated SKY; also called chromosome painting. A cytogenetic blood test used to see all the pairs of chromosomes in a cell in different colors. See also chromosome, cytogenetics.

    speech therapist

    a health professional who is specially trained to work with people to help them communicate clearly. Speech therapists help re-establish communication skills and also make sure that patients can eat and drink.


    the mature male reproductive cell that must combine with an egg (ova) to make a baby. Males start making sperm in their testicles after puberty. See also ova.

    sphincter [sfink-ter]

    a ring-like muscle that can open and close to control the passage of substances in the body. The urethral sphincter squeezes the urethra shut and provides urinary control. There are 2 of these muscles in the anus to control stool (feces), called the external and internal anal sphincters. See also anus, urethra.

    spinal cord

    a long bundle of nerves that a makes up part of the central nervous system. It runs up the back enclosed inside the vertebrae (bones of the spine) and connects to the brain. It shuttles messages between the body and the brain, carrying sensory information from the body to the brain and motor information (signals to move body parts) from the brain to the body. See also brain, vertebra.

    spinal cord compression

    any process that results in pressure on the spinal cord, the spinal nerve trunks, or both. Pressure on the spinal cord can cause numbness, paralysis, or incontinence of stool or urine. This can happen when cancer spreads to the spine. See also spinal cord, incontinence.

    spinal tap

    see lumbar puncture.

    spindle cell [spin-duhl sell]

    a cell that, when seen under a microscope, looks like a long oval. Some types of sarcomas, melanomas, and carcinomas have this type of cell. There are also normal cells of the body that are shaped like spindles. See also carcinoma, melanoma, sarcoma.

    spiral CT

    also called helical CT. A special scanner that takes cross-sectional pictures around the body in a spiral or helix pattern. See also computed tomography scan.


    organ of the immune system in the upper left side of the abdomen (belly) which stores blood, breaks down old blood cells, and helps form some white blood cells such as lymphocytes. See also immune system, lymphocyte.

    sputum cytology [spew-tum sy-tahl-uh-jee]

    a study of mucus or phlegm cells under a microscope to see if they are normal.

    squamous cell carcinoma [skway-mus sell car-sin-O-mah]

    cancer that begins in the flat, non-glandular cells of the body, for example, the skin or the lining of the body’s organs.


    the extent of a cancer, which is usually assigned a number from I to IV. May be called stage grouping. See also staging.


    the process of finding out whether cancer has spread and if so, how far; the process of learning the stage of the cancer. There is more than one system for staging different types of cancer. The TNM staging system, which is used most often, gives 3 key pieces of information.
    • T refers to the size of the tumor
    • N describes whether the cancer has spread to nearby lymph nodes, and if so, how many
    • M shows whether the cancer has spread (metastasized) to other organs of the body
    • Letters or numbers after the T, N, and M give more details about each of these factors. To make this information clearer, the TNM descriptions can be grouped together into a simpler set of stages, labeled with Roman numerals (usually from I to IV). In general, the lower the number, the less the cancer has spread. A higher number means a more serious cancer. The 2 main types of staging are clinical and pathologic.
    • clinical staging is an estimate of the extent of cancer based on physical exam, biopsy results, and imaging tests.
    • pathologic staging is an estimate of the extent of cancer by studying the samples removed during surgery.
    • standard therapy

      also called conventional treatment or mainstream treatment. The most commonly used and most widely accepted form of treatment, which has usually been tested and proven. See also clinical trials, therapy.

      stem cell transplant

      see hematopoietic stem cell transplant.

      stem cells

      any type of cell that may mature into different types of cells. In cancer treatment, the term usually refers to the immature blood cells found in the bone marrow and in the blood. Even though they start out the same, these stem cells can mature into all types of blood cells. See also bone marrow.

      stenosis [steh-no-sis]

      a narrowing (stricture) of a duct or canal. See also duct.


      a very small tube or “straw-like” device that is put in to support and hold open a tube-shaped organ, such as a blood vessel or intestine.

      stereotactic needle biopsy [steer-e-o-TACK-tick need-ul by-op-see]

      a method of needle biopsy that is useful in some cases in which calcifications or a mass can be seen on imaging tests but cannot be felt. A computer maps the location of the mass to guide the placement of the needle. See also biopsy, calcifications, needle aspiration, needle biopsy, imaging studies.

      stereotactic radiosurgery [steer-e-o-TACK-tick ray-dee-o-SUR-jer-ee]

      a treatment method that focuses high doses of radiation at a tumor while limiting the exposure that normal tissue receives. Though it is called surgery, no knife or scalpel is used. The treatment may be useful for tumors that are in places where regular surgery would harm essential tissue, for example, in the brain or spinal cord, or when the patient’s condition does not permit regular surgery. See also radiation, spinal cord.


      also called infertility. The inability to have children, which can result from some types of cancer treatment.


      breastbone, the flat bone where the ribs meet in the center at the front of the chest.

      stoma [sto-muh]

      an opening, especially an opening made by surgery to allow elimination of body waste. See also colostomy, ileostomy, urostomy.

      stomatitis [sto-muh-TIE-tus]

      inflammation, sores, or ulcers of the mouth. Stomatitis can be a side effect of some kinds of chemotherapy.


      solid waste matter; feces.

      stool DNA testing

      a method to detect abnormal deoxyribonucleic acid (DNA) in cells that rub off from colorectal cancers and come out in the stool. This test may prove helpful in screening for colorectal cancer. See also colorectal cancer screening, deoxyribonucleic acid.

      stool softener

      a mild type of laxative that helps keep the stool from becoming hard, dry, and difficult to pass. See also laxative.

      stress incontinence

      passing a small amount of urine when coughing, laughing, sneezing, or exercising. Compare to overflow incontinence, urge incontinence.

      stricture, urethral [strick-chure, yoo-ree-thrul]

      a narrowing of the urethra due to scar tissue that blocks the flow of urine, which can result in overflow incontinence (leaking urine). This can be treated by surgically removing the scar tissue and stretching the urethra. See also overflow incontinence, urethra.

      stroma [stro-muh]

      connective tissue.

      stromal tumor

      see gastrointestinal stromal tumors.

      strontium-89 [stron-tee-um]

      a radioactive substance (radioisotope) that is used for treatment of bone pain from cancer that has spread to the bones. It is injected into a vein and is attracted to areas of bone containing cancer. The radiation given off by the strontium-89 kills the cancer cells, and helps relieve pain. See also radioisotope.

      submucosa [sub-mew-KO-suh]

      a layer of the colon between the muscularis mucosae and the muscularis propria. See also colon wall.

      supraclavicular lymph nodes [sue-pruh-klah-VICK-you-lar]

      lymph nodes that are found just above the collarbone (clavicle). See also lymph node.

      surgeon [sur-jun]

      a doctor who operates.

      surgical biopsy

      also called open surgical biopsy. Removal of tissues using open surgery so that the tissues can be looked at under a microscope to find out if they contain cancer cells. Biopsies may also be done laparoscopically, or with thin needles. See also biopsy, fine needle aspiration biopsy, laparoscope.

      surgical margin

      edge of the tissue removed during surgery. A negative surgical margin means that no cancer cells were found on the outer edge of the removed tissue, and is considered a sign that none of the cancerous mass was left behind. A positive surgical margin means that cancer cells are found at the outer edge of the tissue removed and is usually a sign that some cancer remains in the body.

      surgical oncologist

      a doctor who specializes in using surgery to treat cancer. See also cancer care team.

      survival rate

      the percentage of people still alive within a certain period of time after diagnosis or treatment. For cancer, a 5-year survival rate is often given. This does not mean that people can’t live more than 5 years, nor does it mean that those who live for 5 years are permanently cured. See also five-year relative survival rate.


      not generally used as a medical word, survivor can have different meanings when applied to people with cancer. Some people use the word to refer to anyone who has ever been diagnosed with cancer. For example, someone living with cancer may be considered a survivor. Some people use the term to refer to someone who has completed cancer treatment. Others call a person a survivor if he or she has lived several years past a cancer diagnosis. The American Cancer Society believes that each person has the right to define his or her own experience with cancer and considers a cancer survivor to be anyone who describes himself or herself this way, from diagnosis throughout the rest of his or her life.


      the state of being a cancer survivor, that is, having been diagnosed with cancer. See also survivor.

      symptom [simp-tuhm]

      a change in the body caused by an illness or condition, as described by the person experiencing it. Compare to sign.

      synchronous [sin-kruh-nus]

      occurring at the same time; for example, cancer in both breasts at the same time is synchronous. See also bilateral, metachronous.

      synergistic [sin-er-JIS-tick]

      acting together. A synergistic agent can act together with one or more other agents to produce an effect greater than that of the sum of their individual effects. Some chemotherapy drugs act synergistically. See also chemotherapy.

      systemic disease [sis-tem-ick]

      in cancer, this term means that a cancer that started in one place has spread to distant organs or structures. Compare to in situ, localized cancer.

      systemic therapy [sis-tem-ick]

      treatment that reaches and affects cells throughout the body; for example, chemotherapy. See also chemotherapy. Compare to local therapy.


      T-lymphocytes [limf-o-sites]

      also called T-cells. White blood cells made in the thymus gland. They make cytokines and play a large role in the immune response against viruses, transplanted organs and tissues, and cancer cells. See also cytokines, thymus, white blood cells.

      targeted therapy

      treatment that attacks some part of cancer cells that makes them different from normal cells. Targeted therapies tend to have fewer side effects than chemotherapy drugs with broader action. See also chemotherapy.

      temporary brachytherapy

      see high-dose rate brachytherapy.

      terminal [ter-min-uhl]

      in medicine, generally understood to mean that the disease can no longer be effectively treated or cured, and the patient is dying. See also palliative treatment, hospice.

      testicles or testes [tess-tick-ulls, tess-teez]

      the male reproductive glands normally found in the scrotum. The testicles produce sperm and the male hormone testosterone. See also scrotum, sperm, testosterone.

      testosterone [tes-toss-ter-own]

      called the male hormone, it is made mostly in the testicles. It stimulates blood flow, growth in certain tissues, and secondary sexual characteristics. In men with prostate cancer, it can also make the tumor grow. See also hormone, prostate, testicles.


      also called treatment. Any of the measures taken to treat a disease,. See also alternative therapy, complementary therapy, standard therapy, unproven therapy.

      thermography [thur-mog-ruh-fee]

      a method in which heat from the breast is measured and mapped. This method is not a reliable way to detect breast cancer. The resulting image is called a thermogram.

      thoracic surgeon [thuh-ras-ick sur-jun]

      a doctor who operates on organs in the chest cavity. The word thoracic refers to the thorax, another name for the chest.

      three-dimensional conformal radiation therapy

      also called 3DCRT. Treatment that uses sophisticated computers to very precisely map the location of the cancer within the body. The patient may be fitted with a plastic mold much like a cast to keep them still and in the same position for each treatment so that the radiation can be more precisely aimed. Radiation beams are then aimed from several directions. This reduces the radiation effects on normal tissues and may allow higher doses of radiation to be used. See also external beam radiation therapy, radiation.

      thrombocytopenia [throm-bo-sy-toe-PEEN-ee-uh]

      a decrease in the number of platelets in the blood with an increased risk of bleeding; can be a side effect of chemotherapy. See also chemotherapy, platelet.


      a gland at the base of the neck (behind the upper breastbone or sternum) that helps certain lymphocytes to mature. The thymus is part of the immune system. See also immune system, lymphocyte, sternum.


      a gland at the front of the neck which puts out hormones that regulate how quickly the body uses energy and affects many other body functions. The word thyroid can also refer to certain hormones made by the thyroid gland.

      tibia [tib-ee-uh]

      also called the shinbone. The thicker, inner bone (on the big toe side) of the 2 bones in the lower leg that go from the knee to the ankle. See also fibula.

      tissue [tish-oo]

      a collection of cells that work together to perform a particular function.

      TNM staging system

      see staging.

      total androgen blockade

      see combination hormone therapy.

      total colon exam

      also called TCE. An exam that looks at the entire colon (the large intestine); for examples, see colonoscopy or double contrast barium enema.

      toxicity [tock-sis-i-tee]

      in medical treatment, the harmful effects of a medicine or treatment, especially at higher doses. Can also refer to the effects of poisons or other non-medical substances.

      trachea [tray-key-uh]

      the windpipe. The trachea connects the larynx (voice box) with the bronchi (the 2 large air passages that lead into the lungs) and serves as the main passage for air coming from the nose and mouth into the bronchi and lungs.

      tracheostomy [tray-key-AH-stuh-me]

      surgery to create an opening of the trachea through the neck. See also trachea.

      transfusion [trans-few-zhun]

      blood or blood products that are given into a vein (intravenous or IV). Most such products are taken from unrelated donors and tested for disease before use, but a person can donate their own blood ahead of time to be given during certain planned surgeries or procedure.

      transition zone [tran-zi-shun]

      in the prostate, this is the innermost area that surrounds the urethra. This is where benign prostatic hyperplasia (BPH) develops. See also benign prostatic hyperplasia (BPH), prostate, urethra.

      translocation [tranz-low-KAY-shun]

      genetic material that is out of its normal place, as when deoxyribonucleic acid (DNA) from one chromosome breaks off and gets attached to a different chromosome. See also chromosome, deoxyribonucleic acid, mutation.

      transrectal ultrasound [trans-rek-tul ul-truh-sound]

      also called TRUS. An imaging test in which a probe is put in the rectum, where it puts out sound waves to make a picture of the prostate on a screen to help find tumors. See also prostate, rectum.

      transurethral resection of the prostate [trans-yoo-REE-thrul re-sek-shun]

      also called TURP. An operation that removes a part of the prostate gland that surrounds the urethra (the tube through which urine exits the bladder). The procedure is used for some men with prostate cancer who cannot have the prostate removed (radical prostatectomy) because of advanced age or other serious illnesses. This operation can be used to relieve symptoms caused by a tumor, but it is not expected to cure this disease or remove all of the cancer. TURP is used more often to relieve symptoms of benign prostatic hyperplasia (BPH). See also benign prostatic hyperplasia (BPH), prostate.

      transverse colon [trans-verse ko-lun]

      the second section of the colon, a part of the large intestine. It is called transverse because it goes across the body from the right to the left side. See also colon, ascending colon, descending colon, sigmoid colon.

      transverse rectus abdominus muscle flap procedure [trans-verse rek-tus ab-dom-in-us]

      also called a TRAM flap or rectus abdominus flap procedure. A method of breast reconstruction in which tissue from the lower abdominal wall (belly) which receives its blood supply from the rectus abdominus muscle is used. The tissue from this area is moved up to the chest to create a breast mound. An implant is usually not needed. Moving muscle and tissue from the lower abdomen to the chest results in flattening of the lower abdomen (a “tummy tuck”). See also breast reconstruction.

      triple-negative breast cancer

      breast cancer that does not have estrogen receptors, progesterone receptors, or human epidermal growth factor receptor 2 (HER2). This limits the effective treatment options for patients. See also estrogen receptor assay, human epidermal growth factor receptor 2, progesterone receptor assay.


      see transrectal ultrasound.

      tubular adenoma [tube-yoo-ler ad-no-muh or ad-uh-NO-muh]

      a benign (non-cancerous) polyp made of gland cells formed into tubes, in which the tubular structure generally makes up more than 75% of the adenoma. They usually cause no symptoms, and are often found during screening procedures such as colonoscopy. Because they are pre-cancerous, they are generally removed when found. See also adenomatous polyp, colonoscopy, polyp, tubulovillous adenoma, villous adenoma.

      tubular carcinoma [tube-yoo-ler car-sin-O-muh]

      a rare type of low-grade invasive breast cancer that accounts for about 2% of invasive breast cancers. The outlook for this kind of cancer is considered to be better than average. See also invasive cancer.

      tubulovillous adenoma [tube-yoo-lo-VIH-lus ad-no-muh or ad-uh-NO-muh]

      a benign (not cancer) polyp made of gland cells formed into tubes, along with finger-like projections of gland cells when seen under a microscope. In these, the finger-like parts usually make up 25% to 50% of the adenoma. These adenomas are pre-cancerous, and are generally removed when found. See also adenomatous polyp, polyp, tubular adenoma, villous adenoma.

      tumor [too-mer or tyoo-mer]

      an abnormal lump or mass of tissue. Tumors can be benign (not cancer) or malignant (cancer).

      tumor flare

      short-term worsening of symptoms or tumor markers. See also symptoms, tumor markers.

      tumor markers

      substance made by cancer cells and sometimes normal cells. They are not very useful for cancer screening because other body tissues not related to a cancer can produce these substances, too. But tumor markers may be very useful in watching for a response to treatment after a cancer is diagnosed or looking for cancer that has come back (recurred).

      tumor necrosis factor [too-mer or tyoo-mer neck-row-sis]

      also called TNF. A substance given off by activated white blood cells that can cause the death of tumor cells. See also necrosis, white blood cells.

      tumor suppressor genes

      genes that slow down cell division or cause cells to die at the right time. Changes or mutations in these genes can lead to too much cell growth and development of cancer. See also gene, mutation.

      tumor volume

      measure of the amount of cancer present.


      see transurethral resection of the prostate.

      two-step procedure

      a method in which the procedure to diagnose the presence of breast cancer (biopsy) and breast surgery for cancer treatment (such as lumpectomy or mastectomy) are done as 2 separate procedures, days or even weeks apart. This method is often preferred by women and their health care teams because it gives them time to consider all options. Compare to one-step procedure. See also biopsy, lumpectomy, mastectomy.


      ulcerative colitis [ul-suh-ruh-tiv kuh-lie-tis]

      a type of inflammatory bowel disease. In this condition, the colon is inflamed over a long period of time. This increases a person’s risk of developing colon cancer, so starting colorectal cancer screening earlier and doing these tests more often is recommended. See also colon, Crohn’s disease, inflammatory bowel disease.

      ulna [uhl-nuh]

      of the 2 bones in the forearm that go from the elbow to the wrist, this is the one on the same side as the little finger. See also radius.

      ultrasound or ultrasonography [ul-truh-sound or ul-truh-son-AH-gruf-ee]

      imaging test in which high-frequency sound waves are used to outline a part of the body. The sound wave echoes are picked up and displayed on a computer screen. See also imaging studies.

      umbilical cord blood transplant

      the use of stem cells in blood that has been taken from the umbilical cords of newborns to replace the blood-forming stem cells in patients whose own stem cells have been destroyed by radiation or chemotherapy. See also chemotherapy, hematopoietic stem cell transplant, radiation, stem cells.

      unilateral [yoo-nih-LAT-uh-ruhl]

      affecting only one side of the body. For example, unilateral breast cancer occurs in one breast only. Compare to bilateral.

      unproven therapy

      any therapy that has not been scientifically tested and shown to work.

      unstaged cancer

      cancer that has been diagnosed but has not yet been staged, so the full extent of the cancer is not yet known. See also staging.

      ureter [your-uh-ter or yoo-ree-ter]

      a tube that carries urine from each kidney to the bladder. A person normally has 2 ureters. See also bladder, kidney, urethra.

      urethra [yoo-ree-thruh]

      the tube that carries urine from the bladder to outside the body. In women, this tube is fairly short. In men it is longer, passing through the prostate and the penis, and it also carries the semen. See also bladder, kidney, prostate, semen, ureter,.

      urge incontinence

      a sudden and uncontrollable urge pass urine. This happens when the bladder becomes too sensitive to stretching when it gets full of urine. Compare to stress incontinence, overflow incontinence.


      feeling the need to urinate (pass urine) right away.

      urinary frequency

      the need to urinate (pass urine) often.

      urinary incontinence

      partial or complete loss of urine control. See also overflow incontinence, stress incontinence, urge incontinence.

      urinary retention

      being unable to empty the bladder or unable to urinate (pass urine). See also bladder.

      urinary tract

      the system that helps to balance certain chemicals and fluids, and filter the blood. It includes the kidneys, ureters, bladder, and urethra. See also bladder, kidney, ureter, urethra.

      urinate [YUR-uh-nate]

      to release urine from the bladder. See also bladder.

      urine cytology [yur-in sy-tahl-uh-jee]

      urine is examined under a microscope to look for cancer and pre-cancer cells. Cytology can also be done on bladder washings. Bladder washing samples are taken by putting a salt solution into the bladder through a tube (called a catheter) and then removing the solution for testing. See also bladder.

      urodynamic study [yur-o-die-NAM-ick]

      test to evaluate function of the bladder muscle and sphincters. See also bladder, sphincter.

      urologist [yur-ahl-uh-jist]

      a doctor who specializes in treating problems of the urinary tract in men and women, and problems in the genital area in men. See also urinary tract.

      urostomy [yur-ahs-tuh-me]

      surgery to send urine through a new passage and then through an opening in the abdomen (belly). In a continent urostomy, the urine is stored inside the body and drained a few times a day through a tube placed into an opening called a stoma. See also stoma.

      uterine fibroid tumor [yew-ter-in fi-broyd too-mer or tyoo-mer]

      also called a fibroma. A non-cancerous tumor that is made of fibrous or connective tissue. It is the most common tumor found in women. It can be in the uterine wall or protrude into the lining of the uterus. Usually there are no symptoms, but it can cause abnormal bleeding and other symptoms depending on its size and location in the uterus. See also uterus, leiomyoma.

      uterus [yew-tuh-rus]

      also called the womb. The pear-shaped organ in a woman’s pelvis that holds and nourishes the growing embryo and fetus. The uterus is divided into 3 areas; the body is the upper part, the isthmus is the narrowed central area, and the cervix is at the base.


      vaccine [vack-seen]

      a modified version of a germ or other substance related to a disease, usually given by injection (a shot). It is used to stimulate the immune system to resist that disease for a period of time, or even permanently. For instance, the HPV vaccines help to prevent cancer by helping the body fight human papilloma virus (HPV), which can cause many types of cancer. Research continues into vaccines to help a person who has cancer, with recent progress in prostate cancer treatment.

      vacuum device or vacuum pump

      a device that creates an erection by drawing blood into the penis; a ring placed at the base of the penis then traps the blood and keeps the erection. See also impotence.

      vagina [vuh-jie-nuh]

      the passage leading from the vulva (the female genital organs that are on the outside of the body) to the uterus (the womb).

      vaginitis [va-juh-NY-tus]

      any inflammation of the vagina. Atrophic vaginitis is an inflammation of the vagina in which vaginal tissue becomes thin and dry. This condition often occurs after menopause and is caused by lack of estrogen. It may be relieved by an estrogen cream, ring, or tablet that is placed in the vagina. Vaginitis can also be a side effect of chemotherapy. See also,chemotherapy, estrogen, menopause, vagina.

      vas deferens [vass def-er-ens]

      one of 2 muscular tubes that carry sperm from the testicles to the seminal vesicles. See also seminal vesicles, sperm, testicles.

      vascular endothelial growth factor or VEGF [vas-ku-lur en-doe-THEE-lee-uhl]

      a protein that helps tumors form new blood vessels. See also angiogenesis.

      vasectomy [vuh-seck-tuh-me]

      surgery in which a segment of each vas deferens is removed to prevent release of sperm and thus prevent pregnancy. See also sperm, vas deferens.

      vertebra [ver-tuh-bruh]

      one of 33 bones that is stacked and interlocked to form the spinal column; the spinal cord runs through these bones . The plural is vertebrae (ver-tuh-bray). See also spinal cord, spine.

      villous adenoma [vih-lus ad-no-muh or ad-uh-NO-muh]

      a benign (not cancer) polyp inside the colon or rectum with finger-like projections of gland cells that can be seen under the microscope. These finger-like structures generally make up at least half of the adenoma. Villous adenomas are usually broad-based, pre-cancerous lesions, and often cause rectal bleeding. They are usually removed when found. See also adenomatous polyp, colon, polyp, rectum, tubular adenoma, tubulovillous adenoma.

      villous changes [vih-lus]

      a polyp or mass that has some finger-like projections of gland cells when seen under the microscope. If there are enough of these, the mass would be considered a villous or tubulovillous polyp. See also adenomatous polyp, colon, polyp, tubular adenoma, tubulovillous adenoma, villous adenoma.

      virtual colonoscopy

      examination of the colon for polyps or masses using special computed tomography (CT) scans. The images are combined by a computer to make a 3-dimensional (3-D) model of the colon, which doctors can “fly-through” on a computer screen. See also colon, colonoscopy, computed tomography scan, polyp.

      virus [vy-rus]

      very small organisms (called micro-organisms) that cause infections. Viruses are too small to be seen with a regular microscope. They can grow and reproduce only in living cells.


      Waldenstrom macroglobulinemia [wal-den-strom mack-row-glob-yuh-lin-EE-mee-uh]

      also called lymphoplasmacytic lymphoma. A type of non-Hodgkin lymphoma that makes large amounts of an abnormal protein (called a macroglobulin). The lymphoma cells grow mainly in the bone marrow and crowd out normal blood cells. See also bone marrow, macroglobulinemia, non-Hodgkin lymphoma.

      watchful waiting

      see expectant management.

      white blood cells [WBCs]

      blood cells that help defend the body against infections. There are many types of white blood cells. Certain cancer treatments such as chemotherapy can reduce the number of these cells and make a person more likely to get infections. See also bone marrow, chemotherapy, immune system.

      Whitmore-Jewett staging system

      classification system for prostate cancer using the categories A, B, C, or D. It has largely been replaced by the TNM system. Whitmore-Jewett staging can be translated into the TNM system, or the doctor can explain how this staging system will affect treatment options. See also prostate, staging, Gleason score.

      wire localization [lo-cull-ih-ZAY-shun]

      a method used during a surgical biopsy when the lump is hard to find or when there is an area that looks suspicious on the x-ray. A thin, hollow needle is placed into the tissue and x-rays are taken to guide the needle to the area of concern. A fine wire is put through the center of the needle. A small hook at the end of the wire keeps it in place. The hollow needle is then removed, and the surgeon uses the path of the wire as a guide to find the abnormal area to be removed. See also biopsy.



      one form of radiation that can be used at low levels to make an image of the body on film or at high levels to kill cancer cells. See also imaging studies.



      see three-dimensional conformal radiation therapy.

      5-alpha reductase [al-fuh re-duck-tace]

      an enzyme that converts testosterone to a more active hormone called dihydrotestosterone (DHT). Drugs such as finasteride (Proscar® or Propecia®) that prevent this conversion are called 5-alpha reductase inhibitors and may help reduce the risk of prostate cancer. See also prostate, testosterone.

      5-year relative survival rate

      see five-year relative survival rate.

      5-year survival rate

      see five-year survival rate.