Breast Cancer Glossary of Medical Terms

Ablative therapy: Treatment that involves the removal or destruction of the function of an organ, as in the surgical removal of the ovaries or the administration of some types of chemotherapy that causes the ovaries to stop functioning.

Abscess: A closed pocket of tissue containing pus (a creamy, thick, pale yellow or yellow-green fluid that comes from dead tissue); most commonly caused by a bacterial infection.

Accessory breast tissue: An uncommon condition in which additional breast tissue is found in the axillary (underarm) area.  Women with this condition often require special mammography views.

Acini: Another term for the lobules of the breast.  Lobules are milk-producing glands. 

Adenocarcinoma: Cancer that originates in the glandular tissue, such as in the ducts or lobules of the breast.

Adenoma: A benign growth originating in the glandular tissue of the breast that can compress adjacent tissue as it grows in size.  (See also fibroadenoma).

Adjuvant therapy: Additional treatment that is added to increase the effectiveness of a primary therapy. Common types of adjuvant therapy include: hormonal therapy, chemotherapy, or radiation added after surgery to increase the chances of curing the disease or keeping it in check.  

Adrenal gland: One adrenal gland is located near each kidney. Their main function is to produce hormones that regulate metabolism and control fluid balance and blood pressure. Adrenal glands also produce small amounts of “male” hormones (androgens) and “female” hormones (estrogens and progesterone).

Advanced cancer: A stage of cancer in which the disease has spread from the primary site to other parts of the body. When the cancer has spread only to the surrounding areas, it is called locally advanced. If it has spread further by traveling through the bloodstream, it is called distantly advanced or metastatic.

Alopecia: Hair loss. Temporary alopecia often occurs as a result of chemotherapy or less commonly, when radiation therapy is administered to the head.

Alternative treatment: See therapy.

Anastrozole (brand name, Arimidex): See Arimidex. 

Androgen: A male sex hormone. Androgens may be used to treat recurrent breast cancer. Their purpose is to oppose the activity of estrogen, thereby slowing growth of the cancer.

Anesthesia: The loss of feeling or sensation as a result of drugs or gases. General anesthesia causes loss of consciousness (“puts you to sleep”). Local or regional anesthesia causes loss of feeling only to a specified area.

Aneuploid: An abnormal number of chromosomes; a characteristic of cancer. (See also ploidy).

Antibiotic:  Chemical substances, produced by living organisms or synthesized (created) in laboratories, for the purpose of killing other organisms that cause disease. Some cancer therapies interfere with the body’s ability to fight off infection (they suppress the immune system), so antibiotics may be needed along with the cancer treatment to prevent or treat infections. 

Antibody: An immune system protein in the blood that defends against invading foreign agents, such as bacteria. Invading agents contain certain chemical substances called antigens. Each antibody works against a specific antigen. (See also antigen).

Antiemetic: Also spelled antemetic.  A drug used to control nausea and vomiting (emesis), which are common side effects of chemotherapy. Antiemetic drugs can be used before, during, or after chemotherapy. Granisetron and ondansetron are examples of antiemetic drugs.

Antiestrogen: A substance that blocks the effects of the hormone estrogen on tumors (for example, the drug tamoxifen). Antiestrogens are used to treat breast cancers that depend on estrogen for growth.

Antigen: A chemical substance that stimulates an immune system response. This reaction often involves production of antibodies. For example, the immune system’s response to antigens that are part of bacteria and viruses helps people resist infections. Cancer cells have certain antigens that can be detected by laboratory tests, and are important in cancer diagnosis and in monitoring response to treatment. Other cancer cell antigens play a role in immune reactions that may help the body’s resistance against cancer.

Antimetabolites:  Substances that interfere with the body’s chemical processes, such as creating proteins, DNA, and other chemicals needed for cell growth and reproduction. In treating cancer, antimetabolite drugs interferes with DNA production, which in turn prevents cell division and growth of tumors. (See also DNA).

Areola: The dark pigmented area that encircles the nipple.

Arimidex (generic name, anastrozole): A drug sometimes used to treat advanced breast cancer in post-menopausal women who have not responded well to treatment with the drug tamoxifen.

Aromasin: Brand name of exemestane. Drug used to treat metastatic breast cancer in post-menopausal women. Works by binding to the body’s aromastase enzyme, an enzyme responsible for producing the hormone, estrogen. 

Aspiration: Removal of tissue or fluid from a lump or cyst with a needle and syringe.  (See also needle aspiration).

Asymmetry: An area that is not found to be identical in both breasts (such as tissue density).  It is often a normal variant but can also be a sign of an abnormal growth.