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Cancer Glossary

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

See dilation and curettage.
 Search  [de-BULK]
To surgically reduce the volume or amount of cancer, usually by removing as much as can be safely taken out.
 Search  [dee-OK-see-RI-bo-noo-KLEE-ick]
Most often called DNA. The genetic “blueprint” found in the center (nucleus) of each cell. DNA makes up the genes in each cell, which control its growth, division, and function. See also gene, mutation.
 Search  [DEE-poe or DEP-oh]
A shot (injection) 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.
 Search  [DER-muh-TAHL-uh-jist]
A doctor who specializes in skin diseases.
See diethylstilbestrol.
 Search  [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 finding the disease at an early stage, when it’s easier to treat, before it has grown large or spread. Certain tests can be used before a person has any symptoms to try to find cancer early. See also screening.
See dihydrotestosterone.
 Search  [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, a biopsy is needed to be sure of the diagnosis. See also biopsy, imaging studies, sign, symptom.
 Search  [DIE-uh-FRAM]
A thin, dome-shaped muscle that separates the chest from the belly (abdomen). During breathing, the diaphragm moves down to pull air into the lungs, and up to push it out.
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.
 Search  [die-ETH-ul-still-BES-trahl]
Often shortened to DES. A man-made form of estrogen that was sometimes used during pregnancy in the past. People whose mothers took DES while pregnant with them may have a higher risk of certain cancers and reproductive problems. Women who took this drug while pregnant may be at a slightly higher risk of breast cancer. It’s no longer available in the United States. See also estrogen.
 Search  [DIE-uh-TISH-un]
An expert in the area of nutrition, 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.
 Search  [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. Tumor grading systems are based on the degree of differentiation. See also grade.
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. See also gastrointestinal tract.
A way of storing an x-ray picture of the breast (mammogram) as a computer image rather than on the usual x-ray film. See also mammogram.
Often shortened to 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 generally is not painful, can be used to check for rectal cancers and some prostate cancers. See also prostate, rectum.
 Search  [die-HI-dro-tes-TOSS-ter-OWN]
Often shortened to DHT. 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.
 Search  [die-LAY-shun and CURE-uh-TAZH]
Often shortened to D & C. A procedure in which the cervix is opened slightly so that tissue from the lining of the womb (uterus) 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.
 Search  [DIP-loyd]
Cells with 23 pairs of chromosomes, such as is found in normal human cells. Compare to aneuploid. See also chromosome, ploidy.
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.
 Search  [di-SEK-shun]
Surgery to divide, separate, or remove tissues. See also axillary dissection.
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.
 Search  [DIE-ver-TICK-you-LIE-tis]
Inflammation in 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.
The process of fixing the genetic mistakes inside a cell that are sometimes made when it divides to make new cells. 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.
Giving the usual doses of chemo closer together (such as every 2 weeks rather than every 3 weeks). This schedule requires the use of drugs called growth factors to help prevent blood cell counts from getting too low. See also chemotherapy, growth factors
 Search  [doe-SIM-uh-trist]
A person who plans and calculates the correct radiation dose for each patient’s cancer treatment. See also radiation therapy.
A type of x-ray that can be used to help look for problems in the colon and/or rectum. Barium sulfate, a chalky liquid, 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 can then be seen on x-ray films. Also called DCBE, air-contrast barium enema, or barium enema with air contrast. See also barium enema, colon, rectum, x-ray.
For cancer in general, the time it takes for a cell to divide or for a tumor to double in size. Tumors vary in doubling time from 8 to more than 1,000 days. Thus, a cancer may be present for many years before it can be found.
See digital rectal exam.
The ability of cells to resist the effects of drugs used to kill or weaken them.
A hollow passage through which body fluids such as bile or saliva leave the glands where they are made. In the breast, milk passes from lobules (which make the milk) through ducts to the nipple. See also glands.
 Search  [ek-TAY-zhuh]
Widening of the ducts of the breast, often related to breast inflammation called periductal mastitis. Duct ectasia is not cancer.
 Search  [DUCK-tul CAR-sin-O-ma in SY-too]
Also called DCIS or intraductal carcinoma. A condition in which cancer cells are in lining of the milk passages (ducts) but have not grown through the duct walls into the nearby tissue.
 Search  [DUCK-tuh-GRAM]
A test in which a very thin 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.
One of the staging systems for colorectal cancer, which uses the letters A through C. See also staging, colorectal cancer.
A legal document that lets you appoint a person to make medical decisions for you if you become unable to do so for yourself. This is a type of advance directive. Compare to living will. See also advance directives.
 Search  [dis-FAY-zhe-uh]
Trouble swallowing.
 Search  [dis-PLAY-zhuh]
Abnormal cell changes that can be seen with a microscope and may lead to cancer.