What is hormone therapy?

Hormone therapy is most commonly used to treat symptoms of menopause, including hot flashes, night sweats, osteoporosis, mood swings and sleep disorders.

However, hormone therapy is also used as adjuvant and neoadjuvant therapy in women who have been diagnosed with breast cancer to decrease the risk for recurrence and to treat breast cancer that has recurred or spread. It is also used for prostate cancer in men (eg, androgen deprivation therapy) to decrease or block androgen levels — such as testosterone — that are known to affect prostate cancer cells.

Hormone therapy for women is available in various forms — including pills, skin patches, gels, and as vaginal creams or rings — that consist of one or more of the female hormones estrogen and progesterone. In men, it is available in the form of shots or as small pellets of medicine placed under the skin.

The different types of hormone therapy in women include therapies that block estrogen and therapies that decrease levels of estrogen. For women with hormone receptor-positive invasive breast cancer, tamoxifen, toremifene and fulvestrant may be prescribed. Aromatase inhibitors are used to lower estrogen levels.

In men, orchiectomy, luteinizing hormone-releasing hormone (LHRH) analogs and LHRH antagonists lower androgen levels, and anti-androgens stop androgens from working.

Benefits of hormone therapy

The known benefits of hormone therapy in women are many. Women are relieved from the hot flashes, night sweats, sleep disturbances, anxiety and vaginal dryness that are experienced during menopause. Osteoporosis is also prevented with hormone therapy.

The risk for cancers that are hormone receptor-positive is increased by high levels of estrogen. For the types of breast cancers that are estrogen or progesterone receptor-positive, hormone therapy decreases estrogen levels or stops estrogen from promoting breast cancer cells.

Androgen deprivation therapy is used in men with prostate cancer who are not able to undergo surgery or radiation treatment or cannot be cured by these treatments because the cancer has spread too far. The therapy is also used in addition to radiation therapy to prevent the cancer from returning after treatment or is used to shrink prostate cancer before a patient undergoes radiation in order for treatment to be more effective.

Risks of hormone therapy

Although there are many benefits of hormone therapy, there also are known risks. Women who have been diagnosed with breast cancer and are taking hormone therapy may experience fatigue, hot flashes and mood swings. A tumor may flare in women with bone metastases, causing swelling and pain in the muscles and bones. In others, hormone therapy may need to be stopped if high calcium levels cannot be controlled in the blood.

In rare cases, some women who have experienced menopause may go on to develop endometrial cancer or uterine sarcoma caused by hormone therapy. Other risks include blood clots in the lower part of the leg, strokes, heart attack and bone thinning in premenopausal women.

For men, the risks associated with use of hormone therapy include hot flashes, osteoporosis, anemia, decreased mental sharpness, loss of muscle mass, weight gain, fatigue, increased cholesterol and depression. However, according to the American Cancer Society, the benefits outweigh the risks of hormone therapy.

Looking ahead

Research is ongoing on hormone therapy use for cancer. Specifically, researchers are examining the effect of epigenetic-immune modification on reversing hormone-therapy resistance in women with breast neoplasms. In addition, researchers are assessing Ra-223 dichloride in combination with hormone therapy plus denosumab (Xgeva, Amgen) for the control of breast cancer that has spread to the bones and bone marrow.

A major area of research for hormone therapy in men includes a study examining whether DCVAC/PCa plus hormone therapy can improve PSA progression times in a population of men with metastatic prostate cancer.

For more information:

www.nlm.nih.gov/medlineplus/ency/article/007111.htm

www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-treating-hormone-therapy

www.cancer.org/cancer/prostatecancer/overviewguide/prostate-cancer-overview-treating-hormone-therapy