Hormone Therapy

Hormones can cause tumors to grow. Hormone therapy (anti-hormones) blocks this stimulation and keeps cancer cells from growing. Hormone therapy can also help prevent new cancers from growing. It is a treatment option for people whose cancerous tissue tests positive for certain hormone receptors.

There are two main hormone categories for breast cancer. If your breast cancer is estrogen and/or progesterone positive, you may need anti-hormonal therapy. Women whose estrogen and progesterone receptors are negative will likely not be candidates for hormone therapy.

  • Anti-estrogens. This group includes tamoxifen (Nolvadex), toremifene (Fareston®) and raloxifene (Evista). These anti-hormones block the estrogen produced by the ovaries and may also help prevent bone loss. If a woman with positive receptors has not gone through menopause, she will likely receive anti-estrogens.
  • Aromatase inhibitors. This group includes anastrozole (Arimidex®), letrozole (Femara®) and exemestane (Aromesin®). These anti-hormones block estrogen produced by other tissues after menopause. If a woman with positive receptors has gone through menopause, she will likely receive an aromatase inhibitor.