Cancer Dictionary – D
diagnosis The process of identifying a disease by the signs and symptoms.
diaphragm (DY-uh-fram) The thin muscle below the lungs and heart that separates the chest from the abdomen.
differentiation In cancer, refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably.
diffuse Widely spread; not localized or confined.
disease progression Cancer that continues to grow or spread.
do not resuscitate order (…ree-SUH-sih-TAYT…) DNR order. A type of advance directive in which a person states that healthcare providers should not perform cardiopulmonary resuscitation (restarting the heart) if his or her heart or breathing stops. Also called DNR order.
dose The amount of medicine taken, or radiation given, at one time.
dose-dense chemotherapy (DOSE-dents KEE-moh-THAYR-uh-pee) A chemotherapy treatment plan in which drugs are given with less time between treatments than in a standard chemotherapy treatment plan.
dose-dependent Refers to the effects of treatment with a drug. If the effects change when the dose of the drug is changed, the effects are said to be dose-dependent.
dose-rate The strength of a treatment given over a period of time.
dosimetrist (do-SIM-uh-trist) A person who determines the proper radiation dose for treatment.
dosimetry (doh-SIH-muh-tree) Measurement of radiation exposure from x-rays, gamma rays, or other types of radiation used in the treatment or detection of diseases, including cancer.
double-blinded A clinical trial in which neither the medical staff nor the person knows which of several possible therapies the person is receiving.
drug resistance The failure of cancer cells, viruses, or bacteria to respond to a drug used to kill or weaken them. The cells, viruses, or bacteria may be resistant to the drug at the beginning of treatment, or may become resistant after being exposed to the drug.
drug tolerance A condition that occurs when the body gets used to a medicine so that either more medicine is needed or different medicine is needed.
dysplasia (dis-PLAY-zhuh) Cells that look abnormal under a microscope but are not cancer.