Two articles in this issue of JAMA report results of the National Surgical Breast and Bowel Project Study of Tamoxifen and Raloxifene (STAR) trial, in which 19 747 postmenopausal women at increased risk of breast cancer were randomly assigned to receive either tamoxifen (20 mg/d) or raloxifene (60 mg/d) for a maximum of 5 years. In the first article, Vogel and colleaguesArticle report the trial results for major clinical outcomes. The authors found raloxifene was as effective as tamoxifen in reducing the risk of invasive breast cancer, but women taking raloxifene had anonsignificant increased risk of noninvasive breast cancer. Raloxifene use was associated with fewer thromboembolic events and cataracts and had comparable rates of other cancers, fractures, ischemic heart disease, and stroke compared with tamoxifen. In the second article, Land and colleaguesArticle report the trial findings on patient-reported symptoms and quality of life. Specifically, self-reported physical and mental health declined modestly during the trial, but there were no differences between the tamoxifen and raloxifene groups. Women taking tamoxifen reported better sexual function, but more gynecological problems, vasomotor symptoms, leg cramps, and bladder control problems, whereas women taking raloxifene reported more musculoskeletal problems, dyspareunia, and weight gain. In an editorial, Gradishar and CellaArticle discuss the results of the STAR trial and their implications for women at high risk of breast cancer.