Hormone Therapy
Hormones are naturally occurring substances in the body. They stimulate the growth of hormone sensitive tissues, such as the breast,. and can also stimulate the growth and spread of breast cancer. Two methods help combat hormone dependent breast cancer. The first is by taking certain drugs that can block hormone production or change the way hormones work to fight the cancer throughout the body. The second is remove the ovaries, which secrete hormones.
The breast cancers that are hormonedependent are referred to as estrogen receptor positive (ER+) and progesterone receptor positive (PR+). Receptors are areas on the surfaces of cells where hormones can bind to promote the growth of breast cancer. Doctors can prescribe hormone therapy to block those hormone receptors in order to "starve" the cancer cells. Hormones do not promote the growth of tumors that are estrogen receptor negative (ER-) or progesterone receptor negative (PR-). Patients who have ER- and PR- breast cancers are not candidates for hormone therapy.
Hormone therapy drugs include tamoxifen (Nolvadex) and three others that are collectively referred to as aromatase inhibitors (AIs). All are taken orally each day. Tamoxifen blocks estrogen after it is produced and can reduce the risk of developing breast cancer in the same (ipsilateral) or opposite (contralateral) breast. Tamoxifen may be taken by women who are either premenopausal or postmenopausal as well as by men. Common side effects of tamoxifen include hot flashes, indigestion or feeling sick, sweats, vaginal dryness, vaginal discharge and weight gain. Rare, but more serious, side effects include blood clots (thrombosis), endometrial problems, eye problems and stroke.
AIs include anastrazole (Arimidex), letrozole (Femara) and exemestane (Aromasin). These drugs block the production of estrogen and are not prescribed for premenopausal women Side effects include hot flashes, joint pain, muscle aches, headache, depression and increased risk of bone fracture.
Side effects vary from person to person. Be sure to discuss with your healthcare provider the specific side effects of the drug you will be taking.
Would you like to talk with someone who has taken tamoxifen or an AI? Call the Y-ME Hotline at 800-221-2141 and speak with a trained peer counselor who is a breast cancer survivor.
November 2007
