Cancer Glossary - D

D&C   Dilation and curettage. A minor operation in which the cervix is expanded enough (dilation) to permit the cervical canal and uterine lining to be scraped with a spoon-shaped instrument called a curette (curettage). Also called dilatation and curettage.

D-20761   A synthetic luteinizing hormone-releasing hormone (LH-RH) antagonist that suppresses LH and sex steroid levels.

DACA   Acridine carboxamide. A substance that is being studied as an anticancer drug. It belongs to the family of drugs called topoisomerase inhibitors.

dacarbazine   An anticancer drug that belongs to the family of drugs called alkylating agents.

dacliximab   A monoclonal antibody that is being studied for treatment of adult T-cell leukemia. Also called daclizumab. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

daclizumab   A monoclonal antibody that is being studied for treatment of adult T-cell leukemia. Also called dacliximab. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

dactinomycin   An anticancer drug that belongs to the family of drugs called antitumor antibiotics.

dalteparin   A drug that helps prevent the formation of blood clots; it belongs to the family of drugs called anticoagulants.

danazol   A synthetic hormone that belongs to the family of drugs called androgens and is used to treat endometriosis. It is being evaluated in the treatment of endometrial cancer.

dark-field microscope   A microscope (device used to magnify small objects) in which objects are lit at a very low angle from the side so that the background appears dark and the objects show up against this dark background.

Data Safety and Monitoring Committee   An impartial group that oversees a clinical trial and reviews the results to see if they are acceptable. This group determines if the trial should be changed or closed.

daunorubicin   An anticancer drug that belongs to the family of drugs called antitumor antibiotics.

DCIS   Ductal carcinoma in situ. Abnormal cells that involve only the lining of a duct. The cells have not spread outside the duct to other tissues in the breast. Also called intraductal carcinoma.

de novo  (dih NO-vo) In cancer, the first occurrence of cancer in the body.

decitabine   An anticancer drug that belongs to the family of drugs called antimetabolites.

decortication  (de-KOR-tih-KAY-shun) Removal of part or all of the external surface of an organ.

deferoxamine   An iron-chelating agent that removes iron from tumors by inhibiting DNA synthesis and causing cancer cell death. It is used in conjunction with other anticancer agents in pediatric neuroblastoma therapy.

defibrotide   A drug under study for the prevention of veno-occlusive disease, a rare complication of high-dose chemotherapy and stem cell transplantation in which small veins in the liver become blocked.

degenerative disease   A disease marked by the progressive deterioration of a tissue or organ. Osteoarthritis, osteoporosis, and Alzheimer's disease are examples.

dehydration   A condition caused by the loss of too much water from the body. Severe diarrhea or vomiting can cause dehydration.

dehydroepiandrosterone   DHEA. A substance that is being studied as a cancer prevention drug. It belongs to the family of drugs called steroids.

delayed-type hypersensitivity response   DTH. An inflammatory response that develops 24 to 72 hours after exposure to an antigen that the immune system recognizes as foreign. This type of immune response involves mainly T cells rather than antibodies (which are made by B cells).

dendritic cell   A special type of antigen-presenting cell (APC) that activates T lymphocytes.

dendritic cell vaccine   A vaccine made of antigens and dendritic antigen-presenting cells (APCs).

denileukin diftitox   A substance used to treat cutaneous T-cell lymphoma when other treatments have not worked.

dental implant   A small metal pin placed inside the jawbone to mimic the root of a tooth. Dental implants can be used to help anchor a false tooth or teeth, or a crown or bridge.

deoxycytidine   A drug that protects healthy tissues from the toxic effects of anticancer drugs.

deoxyribonucleic acid   DNA. The molecules inside cells that carry genetic information and pass it from one generation to the next.

DepoFoam-encapsulated cytarabine   The anticancer drug cytarabine formulated inside small particles of a synthetic lipid material called DepoFoam. This dosage form slowly releases the drug and provides a sustained action.

depsipeptide   Anticancer drugs obtained from microorganisms.

derivative   In chemistry, a compound produced from or related to another.

dermatitis   Inflammation of the skin.

dermatofibrosarcoma protuberans  (DER-ma-toe-FI-bro-sar-KO-ma pro-TOO-ber-anz) A type of tumor that begins as a hard nodule and grows slowly. These tumors are usually found in the dermis (the inner layer of the two main layers of tissue that make up the skin) of the limbs or trunk of the body. They can grow into surrounding tissue but do not spread to other parts of the body.

dermatologist  (der-ma-TAH-lo-jist) A doctor who specializes in the diagnosis and treatment of skin problems.

dermis  (DER-mis) The lower or inner layer of the two main layers of tissue that make up the skin.

DES   Diethylstilbestrol. A synthetic hormone that was prescribed from the early 1940s until 1971 to help women with complications of pregnancy. DES has been linked to an increased risk of clear cell carcinoma of the vagina in daughters of women who used DES. DES may also increase the risk of breast cancer in women who used DES.

desmoid tumor   A tumor of the tissue that surrounds muscles, usually in the abdomen. Desmoid tumors rarely metastasize.

desmoplastic small round cell tumor  (dez-mo-PLAS-tik...) A rare, aggressive cancer that usually affects young males and usually is located in the abdomen.

dexamethasone   A synthetic steroid (similar to steroid hormones produced naturally in the adrenal gland). Dexamethasone is used to treat leukemia and lymphoma and may be used to treat some of the problems caused by other cancers and their treatment.

dexrazoxane   A drug used to protect the heart from the toxic effects of anthracycline drugs such as doxorubicin. It belongs to the family of drugs called chemoprotective agents.

dextromethorphan acetic acid   An anticancer drug that belongs to the family of drugs called angiogenesis inhibitors.

DFMO   Difluoromethylornithine. An anticancer drug that has been shown to reduce the risk of cancer in animals.

DHEA   Dehydroepiandrosterone. A substance that is being studied as a cancer prevention drug. It belongs to the family of drugs called steroids.

di-dgA-RFB4 monoclonal antibody   An anticancer drug that is a combination of a monoclonal antibody (RFB4) and an immunotoxin (dgA).

diabetes  (dye-a-BEE-teez) A disease in which the body does not properly control the amount of sugar in the blood. As a result, the level of sugar in the blood is too high. This disease occurs when the body does not produce enough insulin or does not use it properly.

diabetes mellitus  (MEL-ih-tus) A group of disorders in which there is a defect in the transfer of glucose (sugar) from the bloodstream into cells, leading to abnormally high levels of blood sugar (hyperglycemia).

diagnosis   The process of identifying a disease by the signs and symptoms.

diagnostic procedure   A method used to identify a disease.

diagnostic trial   A research study that evaluates methods of detecting disease.

dialysis  (dye-AL-ih-sis) The process of cleansing the blood when the kidneys are not able to filter the blood.

diameter   The length of a straight line that extends from one edge of a tumor or other object, through its center and to the opposite edge. It is usually used to measure the size of round or spherical shapes.

diaphragm  (DYE-a-fram) The thin muscle below the lungs and heart that separates the chest from the abdomen.

diathermy  (DYE-a-ther-mee) The use of heat to destroy abnormal cells. Also called cauterization or electrodiathermy.

diaziquone   AZQ. An anticancer drug that is able to cross the blood-brain barrier and kill cancer cells in the central nervous system.

didanosine   A drug used to treat infection caused by viruses.

DIEP flap   A type of breast reconstruction in which blood vessels called deep inferior epigastric perforators (DIEP), and the skin and fat connected to them are removed from the lower abdomen and used for reconstruction. Muscle is left in place.

diet   The things a person eats and drinks.

diethylstilbestrol  (dye-ETH-ul-stil-BES-trol) DES. A synthetic hormone that was prescribed from the early 1940s until 1971 to help women with complications of pregnancy. DES has been linked to an increased risk of clear cell carcinoma of the vagina in daughters of women who used DES. DES may also increase the risk of breast cancer in women who used DES.

dietitian   A health professional with special training in nutrition who can offer help with the choice of foods a person eats and drinks. Also called a nutritionist.

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.

difluoromethylornithine   DFMO. An anticancer drug that has been shown to reduce the risk of cancer in animals.

digestive system  (dye-JES-tiv) The organs that take in food and turn it into products that the body can use to stay healthy. Waste products the body cannot use leave the body through bowel movements. The digestive system includes the salivary glands, mouth, esophagus, stomach, liver, pancreas, gallbladder, small and large intestines, and rectum.

digestive tract  (dye-JES-tiv) The organs through which food passes when food is eaten. These organs are the mouth, esophagus, stomach, small and large intestines, and rectum.

digital photography   A type of photography in which images can be viewed on a computer screen.

digital rectal examination   DRE. An examination in which a doctor inserts a lubricated, gloved finger into the rectum to feel for abnormalities.

dihematoporphyrin ether   Used in photodynamic therapy, a drug that is absorbed by tumor cells; when exposed to light, it becomes active and kills the cancer cells.

dilation and curettage  (dye-LAY-shun and kyoo-reh-TAHZH) D&C. A minor operation in which the cervix is expanded enough (dilation) to permit the cervical canal and uterine lining to be scraped with a spoon-shaped instrument called a curette (curettage). Also called D&C or dilatation and curettage.

dilator  (DYE-lay-tor) A device used to stretch or enlarge an opening.

dimesna   A drug that belongs to the family of drugs called chemoprotective agents.

dimethyl sulfoxide   A colorless liquid that readily dissolves many chemicals and penetrates animal and plant tissues. It is used in human medicine, veterinary medicine, and pharmaceuticals.

dimethylxanthenone acetic acid   An anticancer drug that belongs to the family of drugs called angiogenesis inhibitors.

dipyridamole   A drug that prevents blood cell clumping and enhances the effectiveness of fluorouracil and other chemotherapeutic agents.

disease progression   Cancer that continues to grow or spread.

disease-free survival   Length of time after treatment during which no cancer is found. Can be reported for an individual patient or for a study population.

disease-specific survival   The percentage of subjects in a study who have survived a particular disease for a defined period of time. Usually reported as time since diagnosis or treatment. In calculating this percentage, only deaths from the disease being studied are counted. Subjects who died from some other cause are not included in the calculation.

disseminate  (dih-SEM-ih-NATE) Scatter or distribute over a large area or range.

distal pancreatectomy   Removal of the body and tail of the pancreas.

distant cancer   Refers to cancer that has spread from the original (primary) tumor to distant organs or distant lymph nodes.

distraction   In medicine, a pain relief method that takes the patient's attention away from the pain.

disulfiram   A drug that slows the metabolism of retinoids, allowing them to act over a longer period of time.

diuretic   A drug that increases the production of urine.

diverticulosis   A condition marked by small sacs or pouches (diverticula) in the walls of an organ such as the stomach or colon. These sacs can become inflamed and cause a condition called diverticulitis, which may be a risk factor for certain types of cancer.

DNA   Deoxyribonucleic acid. The molecules inside cells that carry genetic information and pass it from one generation to the next.

docetaxel   An anticancer drug that belongs to the family of drugs called mitotic inhibitors.

dolasetron   A drug that prevents or reduces nausea and vomiting. It belongs to the family of drugs called antiemetics.

dolastatin 10   An anticancer drug that belongs to the family of drugs called mitotic inhibitors.

donepezil   A drug used in the treatment of Alzheimer's disease. It belongs to the family of drugs called cholinesterase inhibitors. It is being studied as a treatment for side effects caused by radiation therapy to the brain.

dose   The amount of medicine taken, or radiation given, at one time.

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-limiting   Describes side effects of a drug or other treatment that are serious enough to prevent an increase in dose or level of that treatment.

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.

double-blinded   A clinical trial in which neither the medical staff nor the person knows which of several possible therapies the person is receiving.

douche  (DOOSH) A procedure in which water or a medicated solution is used to clean the vagina and cervix.

Down syndrome   A disorder caused by the presence of an extra chromosome 21 and characterized by mental retardation and distinguishing physical features.

doxercalciferol   A substance that is being studied in the prevention of recurrent prostate cancer. It belongs to the family of drugs called vitamin D analogs.

doxorubicin   An anticancer drug that belongs to the family of drugs called antitumor antibiotics. It is an anthracycline.

doxycycline   An antibiotic drug used to treat infection.

DPPE   Belongs to a group of antihormone drugs.

DRE   Digital rectal examination. An examination in which a doctor inserts a lubricated, gloved finger into the rectum to feel for abnormalities.

dronabinol   A synthetic pill form of delta-9-tetrahydrocannabinol (THC), an active ingredient in marijuana that is used to treat nausea and vomiting associated with cancer chemotherapy.

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.

dry orgasm   Sexual climax without the release of semen from the penis.

DTGM fusion protein   An anticancer drug formed by the combination of diphtheria toxin and a colony-stimulating factor (GM-CSF). The colony-stimulating factor is attracted to cancer cells, and the diphtheria toxin kills the cells.

duct  (dukt) A tube through which body fluids pass.

ductal carcinoma   The most common type of breast cancer. It begins in the cells that line the milk ducts in the breast.

ductal carcinoma in situ  (DUK-tal kar-sin-O-ma in SYE-too) DCIS. Abnormal cells that involve only the lining of a duct. The cells have not spread outside the duct to other tissues in the breast. Also called intraductal carcinoma.

ductal lavage   A method used to collect cells from milk ducts in the breast. The cells are looked at under a microscope to check for cancer. A hair-size catheter (tube) is inserted into the nipple. A small amount of salt water flows into the duct and is then removed with the cells in it. Ductal lavage may be used in addition to physical breast examination and mammography to detect breast cancer.

Dukes' classification   A staging system used to describe the extent of colorectal cancer. Stages range from A (early stage) to D (advanced stage).

dumping syndrome   A group of symptoms that occur when food or liquid enters the small intestine too rapidly. These symptoms include cramps, nausea, diarrhea, and dizziness. Dumping syndrome sometimes occurs in people who have had a portion of their stomach removed.

duodenum  (doo-ah-DEE-num) The first part of the small intestine.

DX-52-1   An anticancer drug that belongs to the family of drugs called antitumor antibiotics. It is an anthracycline.

DX-8951f   An anticancer drug that belongs to the family of drugs called topoisomerase inhibitors. Also called exatecan mesylate.

dyscrasia   Disease. Usually refers to diseases of the blood.

dysgeusia   A bad taste in the mouth. Also called parageusia.

dyspepsia   Upset stomach.

dysphagia   Difficulty swallowing.

dysplasia  (dis-PLAY-zha) Cells that look abnormal under a microscope but are not cancer.

dysplastic nevi  (dis-PLAS-tik NEE-vye) Atypical moles; moles whose appearance is different from that of common moles. Dysplastic nevi are generally larger than ordinary moles and have irregular and indistinct borders. Their color frequently is not uniform and ranges from pink to dark brown; they usually are flat, but parts may be raised above the skin surface.

dysplastic nevus  (dis-PLAS-tik NEE-vus) An atypical mole; a mole whose appearance is different from that of a common mole. A dysplastic nevus is generally larger than an ordinary mole and has irregular and indistinct borders. Its color frequently is not uniform and ranges from pink to dark brown; it is usually flat, but parts may be raised above the skin surface.

dyspnea   Difficult, painful breathing or shortness of breath.