Tamoxifen, raloxifene, and the prevention of breast cancer.

The recognition of a new group of drugs, now named selective estrogen receptor modulators (SERMs) has revolutionized prospects for the prevention of breast cancer. New agents will continue to be tested against tamoxifen, the first SERM and an established treatment of ER positive breast cancer. Raloxifene a related SERM is used to treat and prevent osteoporosis with the potential beneficial side effect of preventing breast cancer. The Study of Tamoxifen and Raloxifene (STAR) trial will establish whether raloxifene is an improvement over tamoxifen. Most importantly, emerging information about the molecular pharmacology of SERMs will be used to decipher the mechanism of action at specific target sites around a woman's body. This knowledge can be used to design new SERMs and advance the prospects for multifunctional medicine to prevent breast cancer, osteoporosis and coronary heart disease.