reviewed 9/10/2018

Hormone therapy: True or false?

Hormone therapy helps stop or slow breast cancer growth in women with hormone-sensitive tumors. It isn't the same as hormone replacement therapy for menopause symptoms, though. How much do you know about hormone therapy for breast cancer?

True or false: Hormone therapy is an option for all women with breast cancer.

False. Hormone therapy is used for women with hormone receptor-positive breast cancers. These cancer cells have receptor molecules that attach to the hormone estrogen—and sometimes progesterone—which helps these tumors grow. Hormone therapy doesn't work for tumors that lack these receptors. Most breast cancers are hormone-sensitive, however.

True or false: Hormone therapy works by interfering with, or lowering, estrogen.

True. Tamoxifen and similar drugs interfere with estrogen by keeping it from binding to breast cancer cells. Other hormone therapies (such as aromatase inhibitors) work by blocking estrogen production. Still other options stop the ovaries from producing estrogen—either temporarily with drugs or permanently with surgery.

True or false: Hormone therapy can actually help prevent breast cancer.

True. Hormone therapy is often used after surgery to help keep breast cancer from coming back. Or it may help control breast cancer that has spread. But hormone therapy also helps prevent breast cancer in women at high risk. Tamoxifen and raloxifene can reduce the risk of invasive breast cancer in these women by about 50 percent and 38 percent, respectively.

True or false: Side effects of breast cancer hormone therapy can mimic those of menopause.

True. Common side effects of hormone therapy include hot flashes, night sweats and vaginal dryness. Depending on the type of therapy used, more serious—but less common—side effects can include blood clots, thinning bones, and a somewhat higher risk of uterine and endometrial cancers. For most women, though, the benefits of hormone therapy outweigh the risks.

True or false: Some antidepressants can make hormone therapy less effective.

True. Medicines that might interfere with tamoxifen include a type of antidepressant medicine known as selective serotonin reuptake inhibitors (SSRIs). Evidence suggests they might make hormone therapy less likely to work as well as it should. As a precaution, some doctors prescribe a different type of antidepressant or a different type of hormone therapy.

If you have questions about hormone therapy for breast cancer, talk to your doctor.

Visit the hormones topic center

Sources: American Cancer Society; American Society of Clinical Oncology; National Cancer Institute

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