Breast Cancer Medication
Some breast cancers are hormone dependent. This means that they are stimulated by natural hormones (estrogen or progesterone) that your body produces. By blocking the hormones or decreasing the level of the hormones, hormone treatment can stop your natural hormones from stimulating the cancer.
Hormone therapy can be used to prevent the growth, spread, or recurrence of breast cancer. In some cases, hormone therapy can even be used to prevent breast cancer in people who have a high risk for it.
Although women who have not gone through menopause produce higher levels of hormones, postmenopausal women also produce hormones (although in a different manner). Because the ovaries are a main source of hormones before menopause, surgery to remove the ovaries can be an effective form of hormone therapy for premenopausal women. However, because the ovaries are only a minor source of hormones after menopause, hormone therapy surgery is not usually helpful for postmenopausal women.
In addition to surgery, medications can offer a less drastic (and less permanent) form of hormone therapy. They are also usually easy to take, since they are usually taken by mouth (except fulvestrant, which is given by injection).
One of the most well-known hormone therapies for breast cancer is tamoxifen (Nolvadex®, Soltamox™). This medication acts like estrogen at some receptors and acts like an anti-estrogen at others. In breast tissue, tamoxifen acts like an anti-estrogen, blocking the effects of estrogen. Tamoxifen may increase the risk of uterine cancer or blood clots, but the benefits of the drug often outweigh the possible risks for many women.
Other similar estrogen-blocking breast cancer medications include:
As an alternative to blocking hormones, some hormone therapy medications decrease the production of hormones. These medications are known as aromatase inhibitors. Aromatase is an enzyme in the body that produces estrogen and is a major source of estrogen in postmenopausal (but not premenopausal) women. Aromatase inhibitors include:
(Click Breast Cancer Hormone Treatment for more information.)