Hormone Treatments for Breast Cancer: Basic Facts

Hormone Therapy

If lab tests show that your tumor depended on your natural hormones to grow, it will be called estrogen-receptor-positive or progesterone-receptor-positive.  Such tumors are often sensitive to anti-estrogen treatments , called hormonal therapy. 

Hormone therapy is used to prevent the growth, spread or recurrence of breast cancer by blocking your body's natural hormones from reaching any remaining cancer cells.

Hormone therapy includes medicines that block the effects of estrogen, or having a procedure that either removes the ovaries or makes them unable to produce hormones.

The estrogen-blocking drug tamoxifen (Nolvadex) is one of the most common hormonal therapy drugs. It has been shown to decrease the chance of recurrence in some early-stage cancers and to prevent the development of cancer in the opposite breast. Tamoxifen works by blocking estrogen from attaching to estrogen receptors on cancer cells. By blocking the estrogen receptors, it is believed that the growth of the cancer cells will be halted.

Tamoxifen is effective in pre- and post-menopausal women.

Newer types of hormone therapy are called aromatase inhibitors -- examples are anastrozole and letrozole. They block the production of estrogen in the body, thus lowering the levels of the hormone in the blood.  Armatase inhibitors only work in postmenopausal women.

While on hormone therapy, you should continue to have your yearly pelvic exams, and notify your doctor of any unusual bleeding or pain. The typical length of time you will take tamoxifen or other anti-estrogen drugs is about five years.

Sometimes a treatment called ovarian ablation involves is used to treat breast cancer. Ovarian ablation means making the ovaries of premenopausal woman nonfunctional, either by removing them with surgery or by radiation therapy to the ovaries.