Hormonal Therapy
Hormonal therapies take advantage of the fact that some breast cancers depend on estrogen for their growth. These tumors grow more quickly in the presence of estrogen. Hormonal therapies manipulate the hormonal environment using synthetic substances to block the action or decrease the production of estrogen. When the cancer cells are deprived of hormonal stimulation they reproduce more slowly or not at all, and eventually may die.
Hormone therapy is given primarily to women whose tumors are estrogen- or progesterone-receptor positive. The most common anti-estrogen drug is tamoxifen. It is usually taken daily in pill form for a period of five years. It is used to treat metastatic breast cancer and also to prevent recurrences. Emerging data is establishing the efficacy of a class of drugs called aromatase inhibitors in both the adjuvant and metastatic setting. This class includes anastrazole, letrozole, and exemestane. Other hormonal agents include Megace®, goserelin, and Faslodex® (fulvestrant).
Biologic Therapy
Biologic therapies are similar to hormonal therapies in that they interrupt cellular growth. A new drug, trastuzumab (Herceptin), does this by binding to and inactivating a specific protein that is produced by some cancer cells and causes tumors to grow quickly. The protein is produced when a gene in the cancer cells, the HER2/nue gene, is overactive.
You may also be on new drugs that are part of clinical trials. A promising area of research is with vaccines created to fight substances on cancer cells. Clinical trials on vaccines and other experimental agents are not listed here, but are well described on the informed consent document you will sign if you decide to take part in a trial.
