Words to Know

Data and Safety Monitoring Board

Also called DSMB. 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.


Ductal carcinoma in situ, also called intraductal carcinoma. A noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, DCIS may become invasive cancer and spread to other tissues, although it is not known at this time how to predict which lesions will become invasive.

de novo

In cancer, the first occurrence of cancer in the body.


Surgical removal of as much of a tumor as possible. Debulking may increase the chance that chemotherapy or radiation therapy will kill all the tumor cells. It may also be done to relieve symptoms or help the individual live longer. Also called tumor debulking.

definitive surgery

Final surgery that results in negative (cancer-free) margins.

definitive treatment

The treatment plan for a disease or disorder that has been chosen as the best one for an individual after all other choices have been considered.


A condition caused by the loss of too much water from the body. Severe diarrhea or vomiting can cause dehydration. Some breast cancer treatments can cause dehydration. Symptoms of dehydration include dizziness, headache, decreased urine output, dry mouth, tiredness and listlessness or confusion. Severe dehydration requires immediate medical attention: Symptoms of severe dehydration may include passing out and urinating very little or not at all for 12 or more hours.


Also called AMG 162, Prolia and Xgeva. Denosumab is a medicine used to prevent or treat certain bone problems. In women affected with breast cancer, it may help prevent bone loss linked to use of aromatase inhibitors, a family of medicines used to treat postmenopausal women with estrogen-receptor positive disease. Under the brand name Xgeva, denosumab is used to prevent broken bones and other bone problems caused by solid tumors that have metastasized (spread) to bone. Denosumab binds to a protein called RANKL, and keeps RANKL from binding to another protein called RANK, on the surface of certain bone cells. This may help keep bone from breaking down. Denosumab is a type of monoclonal antibody.


A mental condition marked by ongoing feelings of sadness, despair, loss of energy and difficulty dealing with normal daily life. Other symptoms include feelings of worthlessness and hopelessness, loss of pleasure in activities, changes in eating or sleeping habits and thoughts of death or suicide. Depression can affect anyone and can be successfully treated.


The process of identifying a disease, such as breast cancer, from its signs and symptoms.

diagnostic mammogram

X-ray of the breasts used to check for breast cancer after a lump or other sign or symptom of breast cancer has been found.

diagnostic procedure

A specific test or series of steps done to help diagnose a disease or condition. Mammograms are one example of a diagnostic procedure.

diagnostic technique

A type of method or test used to help diagnose a disease or condition. Imaging tests and tests to measure blood pressure, pulse and temperature are examples of diagnostic techniques.

diagnostic trial

A research study that evaluates methods of detecting disease.


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.


Frequent and watery bowel movements.


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

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.

dietary counseling

Also called nutritional counseling. A process by which a health professional with special training in nutrition helps with healthy food choices and forming healthy eating habits. In breast cancer treatment, the goal of dietary counseling is to help individuals stay healthy during and after treatment and to stay strong enough to fight infections and help prevent the recurrence of disease.

dietary supplement

Also called nutritional supplement. A product that is added to the diet. A dietary supplement is taken by mouth and usually contains one or more dietary ingredient (such as vitamin, mineral, herb, amino acid and enzyme).