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Cancer Glossary

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Browse the glossary by selecting a letter or by entering a cancer-related term:

 Search  [LIM-fo-sites]
Also called T cells. White blood cells that mature in the thymus. 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.
Treatment with drugs that attack some part of cancer cells that’s different from normal cells. Targeted therapies sometimes work when standard chemotherapy drugs don’t, and they tend to have fewer side effects than chemotherapy drugs. See also chemotherapy.
See high-dose rate brachytherapy.
 Search  [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.
 Search  [TESS-tick-ulls, TESS-teez]
The male reproductive glands normally found in the scrotum. The testicles produce sperm and male hormones such as testosterone. See also hormone, scrotum, sperm, testosterone.
 Search  [tes-TOSS-ter-own]
Called the male hormone, it’s made mostly in the testicles. It stimulates blood flow, growth in certain tissues, and secondary sexual characteristics. It can make prostate cancer cells grow. See also hormone, prostate, testicles.
Also called treatment. Any measures taken to fight or treat a disease.
 Search  [thur-MOG-ruh-fee]
A method in which heat from the breast is measured and mapped. The resulting image is called a thermogram. This is not a reliable way to find breast cancer.
 Search  [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.
 Search  [dih-MEN-shuh-nul kun-FOR-mul RAY-dee-AY-shun THAIR-uh-pee]
Often shortened to 3DCRT. Treatment that uses computers to very precisely map the location and the depth, width, and height 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 aimed precisely. Radiation beams are then focused on the tumor from several directions. This reduces damage to normal tissues and allows higher doses of radiation to be used. See also external beam radiation therapy, radiation.
 Search  [THROM-bo-SY-toe-PEEN-ee-uh]
A decrease in the number of platelets in the blood, which can result in an increased risk of bleeding. See also blood count, platelet.
An organ at the base of the neck (behind the upper breastbone) that helps certain lymphocytes mature. The thymus is part of the immune system. See also immune system, lymphocyte.
A gland at the front of the neck which makes 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. See also hormone.
 Search  [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. Compare to fibula.
 Search  [TISH-oo]
A collection of cells that work together to perform a particular function.
See staging.
See combination hormone therapy.
Often shortened to TCE. An exam that looks at the entire colon; for examples, see colonoscopy or double contrast barium enema. See also colon.
 Search  [tocks-IS-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.
An important tumor suppressor gene that’s often changed (mutated) and not working properly in cancer cells. The protein that this gene makes (called p53) normally causes damaged cells to die. Changes (mutations) in this gene can be passed on from a parent (inherited) or they can happen during a person’s life. Inherited TP53 mutations can increase the risk of many types of cancer. See also hereditary cancer syndrome, inherited disease, mutation, tumor suppressor genes.
 Search  [TRAY-key-uh]
Also called the windpipe. The trachea connects the voice box (larynx) with the 2 large breathing tubes that lead into the lungs (bronchi) and serves as the main passage for air coming from the nose and mouth into the bronchi and lungs.
 Search  [TRAY-key-AH-stuh-me]
Surgery to create an opening (stoma) of the trachea through the front of the neck; also used as a term for the opening itself. See also stoma, trachea.
 Search  [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 procedures.
 Search  [tran-ZIH-shun]
Area of passage from one part or condition to another. In the prostate, the transition zone refers to the innermost area that surrounds the urethra, where benign prostatic hyperplasia (BPH) develops. See also benign prostatic hyperplasia, prostate, urethra.
 Search  [TRANZ-low-KAY-shun]
Genetic material that’s out of its normal place, as when DNA (deoxyribonucleic acid) from one chromosome breaks off and attaches to a different chromosome. See also chromosome, deoxyribonucleic acid, mutation.
 Search  [trans-REK-tul UL-truh-sound]
Often shortened to 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.
 Search  [TRANS-yoo-REE-thrul re-SEK-shun]
Often shortened to TURP. An operation to remove the inner part of the prostate gland that surrounds the tube through which urine exits the bladder (the urethra). This procedure is most often used to relieve symptoms of benign prostatic hyperplasia (BPH). See also benign prostatic hyperplasia (BPH), prostate, urine.
 Search  [TRANS-verse KO-lun]
The second section of the colon, a part of the large intestine. It’s called transverse because it goes across the body from the right to the left side. See also colon, ascending colon, descending colon, sigmoid colon.
 Search  [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 belly (abdomen) including the rectus abdominus muscle is moved up to the chest and used 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.
Breast cancer that does not have estrogen receptors, progesterone receptors, or an excess of HER2 (human epidermal growth factor receptor 2). This limits the treatment options for patients. See also estrogen receptor assay, human epidermal growth factor receptor 2, progesterone receptor assay.
See transrectal ultrasound.
 Search  [TUBE-yoo-ler AD-no-muh or AD-uh-NO-muh]
A type of non-cancerous polyp in the colon or other parts of the digestive tract that’s made up of gland cells formed into tubes, in which the tubular structure generally makes up more than 75% of the polyp. Because they can become cancer, they are usually removed. See also adenomatous polyp, colon, digestive system, glandular cells, polyp, tubulovillous adenoma, villous adenoma.
 Search  [TUBE-yoo-ler CAR-sin-O-muh]
A rare type of low-grade invasive breast cancer. See also grade, invasive ductal carcinoma.
 Search  [TUBE-yoo-lo-VIH-lus AD-no-muh or AD-uh-NO-muh]
A type of non-cancerous polyp in the colon or other parts of the digestive tract that’s made up of gland cells formed into tubes, as well as finger-like projections of gland cells. The finger-like parts usually make up 25% to 50% of the polyp. These adenomas can become cancer, and are usually removed. See also adenomatous polyp, colon, digestive system, glandular cells, polyp, tubular adenoma, villous adenoma.
 Search  [TOO-mer or TYOO-mer]
An abnormal lump or mass of tissue. Tumors can be non-cancers (benign) or cancer (malignant).
Short-term worsening of symptoms or increase in tumor markers. See also symptoms, tumor markers.
Substances that can be found in the body (in the blood, urine, or other body fluids or tissues) when a person has cancer. These substances are usually made by cancer cells, but are sometimes by normal cells as well. Different types of cancer can have different tumor markers. For example, prostate-specific antigen (PSA) is a tumor marker for prostate cancer. Ideally, a tumor marker would always be found when a person has a certain type of cancer, and would never be found if a person didn’t have cancer. But in reality tumor markers are rarely like that, because normal cells can often make them as well.

So far, tumor markers haven’t been found to be very useful for cancer screening (looking for cancer in people who don’t have symptoms). But once cancer has been diagnosed, some tumor markers can be helpful in determining treatment options, watching for a response to treatment, looking for cancer that has come back (recurred), or monitoring the progression of advanced cancer. See also screening, advanced cancer.
 Search  [TOO-mer or TYOO-mer neck-ROW-sis]
Often shortened to TNF. A substance made by white blood cells that can cause the death of tumor cells. See also necrosis, white blood cells.
Genes that slow down cell division or cause cells to die at the right time. Changes (mutations) in these genes can lead to too much cell growth and development of cancer. Compare to oncogenes. See also gene, mutation.
Measure of the amount of cancer present.
See transurethral resection of the prostate.
In breast cancer, 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.