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Hormone Therapy for Breast Cancer

What Is Hormone Therapy?

Hormones are chemicals produced by glands in the body that are circulated in the blood. Hormone therapy, also known as hormonal therapy, hormone treatment, or endocrine therapy, is any treatment that adds, blocks, or removes hormones. Endocrine therapy is used to slow or stop the growth of certain cancers, such as prostate and breast cancer. The female hormones estrogen and progesterone, promote the growth of some breast cancer cells. Therefore, endocrine therapy may be given to block the body's naturally occurring estrogen and/or progesterone to fight the cancer's growth. Sometimes, surgery is needed to remove the source of the hormone in question. In the case of breast cancer, the ovaries may be removed if the patient still menstruates.

 

When Is Hormone Therapy Used to Treat Breast Cancer?

Endocrine therapy is used in women with breast cancer whose tumors are sensitive to the hormones estrogen or progesterone (meaning that hormones cause the cancer to grow). Not all breast cancers are hormone-sensitive, so not all breast cancers will respond to a hormone-blocking treatment.

The drugs slow or stop the growth of cancer cells that are present in the body. As an adjuvant (add-on) therapy, endocrine therapy helps prevent the original breast cancer from returning and also helps reduce the risk of the development of new cancers in the other breast.

Women at an increased risk of developing breast cancer (those with a genetic predisposition or family history) have the option of taking endocrine therapy to reduce their chance of ever developing the disease. This is known as risk-reduction therapy. The drugs that may be used in this situation are tamoxifen, fraloxifene or examestane.

 

What Are Common Hormone Drugs Used for Breast Cancer?

Tamoxifen. Tamoxifen, marketed as Nolvadex, is a drug in pill form that interferes with the activity of estrogen. Known as the "antiestrogen," tamoxifen is a drug that has been used for more than 30 years to treat patients with advanced (metastatic or stage IV) breast cancer. It is also used to treat breast cancer in men.

Tamoxifen is also used as additional therapy following surgery for early (stages I and II) and locally advanced (stage III) breast cancer, and as a means of reducing the risk of ever developing breast cancer among women at particularly high risk. Tamoxifen is useful in both premenopausal and postmenopausal women.

Tamoxifen's major side effects are hot flashes, cataract acceleration, and increased risks of blood clotting or cancers/sarcoma of the uterus.

ArimidexFemara, Aromasin. These drugs belong to a class of medications known as aromatase inhibitors. After menopause, a woman's main source of estrogen comes through a process called aromatization, in which male hormones called androgens (produced by the adrenal glands located at the top of the kidneys) are converted into estrogen. This process takes place throughout the body, in the fatty tissue. These drugs fight tumor growth by stopping the conversion of androgens into estrogen.

WebMD Medical Reference

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