Types of Treatment Treatment Guidelines Surgery Chemotherapy Radiation Therapy Drug Therapies

Drug Therapies

Drug therapies may be used alone or in conjunction with other treatments, depending on the type and stage of cancer being treated. There are two categories of drugs used to treat breast cancer:

Hormonal therapy refers to use of drugs that block the effects of estrogen or lower estrogen levels. These drugs are also referred to as antiestrogens or estrogen antagonists. Estrogen is a hormone produced by women's ovaries that promotes the growth of some breast cancers. Tamoxifen is the drug used most often, although there are a number of other drugs that may be used, depending on the patient's individual medical profile. Some studies have shown that there is a slight increase of early stage endometrial cancer (cancer in the lining of the uterus) in women using Tamoxifen, especially if the drug is taken for more than five years. Endometrial cancer is usually diagnosed at an early stage and is almost always curable by surgery.

Other side effects of hormone therapy include weight gain, hot flashes, mood swings, vaginal bleeding, vaginal discharge, induction of premature menopause, headache, nausea, and fluid retention.

Prior to the availability of antiestrogen drugs, oophrectomy, or the removal of a woman's ovaries, was commonly used to treat breast cancer. The ovaries are the main source of estrogen in the body. Today, this procedure is sometimes used in premenopausal women; however, the use of tamoxifen and chemotherapy reduces the need for removal of the ovaries.

Immunotherapy refers to drugs that stimulate the immune system to attack the cancer.

A growth promoting protein known as HER2/neu is present in small amounts on the surface of normal breast cells and most breast cancers. In approximately one-third of all breast cancers, an excessive amount of this protein is present, promoting the aggressive growth and spread of breast cancers. The drug trastuzumab can block the HER2/neu protein from stimulating breast cancer cell growth and may cause the immune system to attack the cancer more aggressively. Trastuzumab is also used to shrink some breast cancer metastases that do not respond to chemotherapy or that recur after chemotherapy.

The side effects of trastuzumab are relatively mild and include fever and chills, nausea, vomiting, cough, diarrhea, and headache.

This website provides general information only. A physician should be contacted if you need any medical advice or if medical decisions need to be made.