Evista is a selective estrogen receptor modulator, or SERM. SERMs have anti-estrogen effects on some tissues and estrogen-like effects on other tissues. They are used to reduce the risk of invasive breast cancer in post-menopausal women that are at a high risk of developing breast cancer. However, it should not be given to women who have already had breast cancer nor should it be used in the treatment of breast cancer.
Incidence and Mortality
Estimated new cases and deaths from breast cancer (men only) in the United States in 2013:
New cases: 2,240.
Male breast cancer is rare. Less than 1% of all breast carcinomas occur in men.[3,4] The mean age at diagnosis is between 60 and 70 years, though men of all ages can be affected with the disease.
Predisposing risk factors  appear to include radiation exposure, estrogen administration, and diseases associated with hyperestrogenism,...
One out of every four cancer diagnoses in women each year is invasive breast cancer. It can be deadly if not caught and treated early.
Noninvasive breast cancer remains in the milk ducts or lobules -- lobes -- of the breast. It does not spread to the surrounding tissue. Invasive breastcancer, though, spreads outward from the milk ducts and lobules into the surrounding breast tissue. Eventually, it spreads to other areas of the body.
Does Evista prevent all types of breast cancer?
Evista prevents invasive breast cancer in post-menopausal women who are at high risk. Evista is the second drug to be approved by the FDA to prevent invasive forms of breast cancer. The first drug, tamoxifen, has been on the market for several decades.
How does Evista reduce the risk of invasive breast cancer?
Evista works by blocking estrogen in the breast tissue of women at high risk. The medication helps prevent the spread of tumors that require estrogen to grow.
Evista is not effective, however, in women who currently have invasive breast cancer or who have had invasive breast cancer. It won't prevent cancer in these women, nor will it treat cancer once it appears.