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Hormone therapy to treat breast cancer

Breast Cancer Hormone Therapy

Hormone therapy is often used after surgery to lower the chance that a breast cancer will come back.

It may also be used for more advanced breast cancers. There are different drugs used in hormone therapy. They all are used to counter the effects of the female hormones, estrogen and progesterone, which in some women promote the growth of certain types of breast cancer cells.

How does hormone therapy target the hormones?

Hormone therapy works against breast cancer cells that have what are called estrogen and/or progesterone "receptors," or proteins on the outsides of the cells that can attach to hormones.

Breast cancer cells can have estrogen receptors (be “ER-positive”), progesterone receptors (be “PR-positive”), both, or neither. Women with receptor-positive cancers tend to have better outlooks for treatment with hormone therapy.

A protein called HER2 may also play a role.

HER2/neu, shortened to HER2, is a protein that causes growth. About 1 out of every 5 breast cancers has too much HER2. Cancers with more HER2 than average tend to spread more aggressively than other breast cancers. These cancers are said to be “HER2-positive.”

Managing the side effects of breast cancer treatment

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US.XON.10.04.011 Last Update: May 2010