Breast cancer is the most common invasive cancer in American women and is second only to carcinoma of the lung in cancer deaths. The results of the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial (BCPT) were released in April 1998. In the BCPT, 13,388 women at increased risk for the development of breast cancer were randomized to receive tamoxifen or placebo for 5 years, resulting in a 49% reduction in invasive breast cancer and a 50% reduction in noninvasive breast cancer. In May 1998, the preliminary results from the Multiple Outcomes of Raloxifene Evaluation (MORE) trial were reported to the American Society of Clinical Oncology. The MORE trial was evaluating the drug raloxifene for the prevention and treatment of osteoporosis; however, a secondary outcome was a reduction in breast cancer risk in raloxifene-treated women. Based upon the results of the BCPT and MORE trials, a second-generation breast cancer prevention trial has been initiated. The Study of Tamoxifen and Raloxifene (STAR) was initiated in June 1999. Ochsner Clinic and Alton Ochsner Medical Foundation, active participants in the BCPT, were named a clinical center for the STAR trial.