Targeted Antiestrogens to Prevent Breast Cancer.

Tamoxifen, the first selective estrogen receptor modulator (SERM), has provided invaluable laboratory and clinical evidence that such drugs can reduce the risk of breast cancer and increase bone density. Raloxifene is available for the prevention of osteoporosis, and preliminary studies show a decrease in breast cancer risk. On the basis of current information about the pharmacology of SERMs, a large breast cancer prevention trial called study of tamoxifen and raloxifene (STAR) has started in the USA. Results should be available in the next seven years.