NCCN Cancer Centers
| The National Comprehensive Cancer Network (NCCN) is a not-for-profit alliance of 23 of the world’s leading cancer centers. We are dedicated to improving the quality and effectiveness of care provided to people with cancer. |
Glossary of terms used on this site
| Term | Definition |
|---|---|
| DCIS |
Ductal carcinoma in situ. 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. Also called ductal carcinoma in situ and intraductal carcinoma. |
| De novo |
In cancer, the first occurrence of cancer in the body. |
| Debulking |
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 patient live longer. Also called tumor debulking. |
| Deductible |
The amount an insured individual must pay toward their medical expenses before their health insurance begins to pay. Most plans have a yearly deductible. |
| Deficiency |
In medicine, a shortage of a substance (such as a vitamin or mineral) needed by the body. |
| Dehydration |
A condition caused by the loss of too much water from the body. Severe diarrhea or vomiting can cause dehydration. |
| Denial of claim |
Refusal by an insurance company to honor a request by an individual (or his or her provider) to pay for health care services obtained from a health care professional. |
| Dermatofibrosarcoma protuberans |
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. These tumors are related to giant cell fibroblastomas. |
| Dermatologist |
A doctor who has special training to diagnose and treat skin problems. |
| Dermis |
The inner layer of the two main layers of the skin. The dermis has connective tissue, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures. It is made up of a thin upper layer called the papillary dermis, and a thick lower layer called the reticular dermis. |
| Dermoid cycst |
A type of benign (not cancer) germ cell tumor (type of tumor that begins in the cells that give rise to sperm or eggs) that often contains several different types of tissue such as hair, muscle, and bone. Also called mature teratoma. |
| Desmoid tumor |
A tumor of the tissue that surrounds muscles, usually in the abdomen. A desmoid tumor rarely metastasizes (spreads to other parts of the body). It may be called aggressive fibromatosis when the tumor is outside of the abdomen. |
| DEXA |
An imaging test that measures bone density (the amount of bone mineral contained in a certain volume of bone) by passing x-rays with two different energy levels through the bone. It is used to diagnose osteoporosis (decrease in bone mass and density). Also called BMD scan, bone mineral density scan, DEXA scan, dual energy x-ray absorptiometric scan, dual x-ray absorptiometry, and DXA. |
| 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. |
| Dialysis |
The process of filtering the blood when the kidneys are not able to cleanse it. |

