Tamoxifen is well established therapy for breast cancer and has preventitive actions on the development of new primary breast cancers. However, there are small risks associated with its prolonged usage (e.g endometrial hypertrophy, thrombosis). Although these side effects are rare, and should not dissuade clinicians from its usage in established breast cancer, nevertheless, they are considerations when contemplating usage of the drug in the prophylactic setting (- i.e to reduce the risk of the subsequent development of cancer (higher risk patients. Raloxifene is another related drug (SERM) that has less validity in the treatment of breast cancer but is widely used for the prevention of post-meopausal osteoporosis. The STAR trial was designed to compare raloxifene with tamoxifenin terms of relative risk of development of subsequent breast cancer. The conclusions of the trial were reported at the American Society of Clinical Oncology annual meeting this year. In summary, raloxifene is an effective alternative to tamoxifen in reducing the risk of developing breast cancer and is associated with fewer of the complications traditionally associated with tamoxifen.