Hormone Therapy for Breast Cancer

About two-thirds of women with breast cancer have tumors that contain hormone receptors. This means a tumor has receptors for the hormone estrogen (called ER-positive) or the hormone progesterone (PR-positive) or both. Hormone therapy blocks these hormones and fight the cancer's growth.

Women who are ER-positive are more likely to respond to hormone treatment than women who are ER-negative.

Tamoxifen

Tamoxifen (Nolvadex, Soltamox) is a pill you take daily. It's been prescribed for decades to treat breast cancer. Women of any age can use it, regardless of whether they've gone through menopause.

Research shows that taking tamoxifen for 5 years lowers the chance of breast cancer recurrence and new breast cancers in women with ER-positive or ER-unknown breast tumors. Doctors also use tamoxifen to treat breast cancer that has spread to other parts of the body. And they use it to prevent breast cancer in healthy women with high odds of developing the disease.

Tamoxifen also helps prevent osteoporosis, or weak bones.

But women who take tamoxifen are more likely to develop cancer of the uterus (endometrial cancer) than other women. You should get regular pelvic exams and tell your doctor about any abnormal uterine bleeding.

Other problems that may happen when you take tamoxifen include blood clots in your legs and lungs (deep vein thrombosis and pulmonary embolism), stroke, and cataracts. Minor side effects include hot flashes and mood swings.

Aromatase Inhibitors

Aromatase inhibitors are medications that treat breast cancer in both early stages and advanced ones. They prevent your body from making estrogen. They only work in women who are past menopause, though.

Anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara) are aromatase inhibitors. Doctors prescribe them to treat ER-positive breast cancer, either following tamoxifen treatment or by themselves.

Palbociclib (Ibrance) works by blocking a protein that controls cell division, so it keeps cancer cells from growing. You take it with letrozole. 

If you've gone through menopause and have hormone receptor positive, HER2-negative advanced breast cancer, you may take ribociclib (Kisqali) with an aromatase inhibitor as initial hormone therapy.

One serious side effect of aromatase inhibitors is osteoporosis, which can lead to bone fractures. You'll need bone density tests to check for osteoporosis.

Other side effects include hot flashes, muscle and joint pain, memory problems, and a greater chance of heart disease.

Continued

Other Medications

Other hormone therapy drugs can treat breast cancer, too. Most, such as fulvestrant (Faslodex) and toremifene (Fareston), are used to treat metastatic breast cancer.

Toremifene, like tamoxifen, blocks certain effects of estrogen. Doctors use it as a treatment for advanced breast cancer in postmenopausal women.

Fulvestrant blocks estrogen receptors temporarily.

Ovarian Ablation

If you haven't yet gone through menopause and have ER-positive cancer, your doctor may want to stop your ovaries from making estrogen. This can be done by:

Your treatment may include both ovarian ablation and hormone therapy. Studies show that giving women an LHRH agonist alone or with tamoxifen is at least as effective as the chemotherapy combination used in hormone-sensitive, early breast cancer and in metastatic breast cancer of premenopausal women.

WebMD Medical Reference Reviewed by Laura J. Martin, MD on April 23, 2017

Sources

SOURCES:

National Cancer Institute.

Breastcancer.org.

Medscape. 

Pfizer Inc.

© 2017 WebMD, LLC. All rights reserved.

Pagination