The 1998 approval of tamoxifen for breast cancer risk reduction opened the era of breast cancer chemoprevention. Women at increased risk for breast cancer now had an option other than healthy lifestyle and prophylactic surgery to reduce risk. However, women and their physicians were reluctant to use tamoxifen because of associated risks. Several trials investigating raloxifene suggested it may reduce breast cancer risk without having an apparent effect on the endometrium. The Study of Tamoxifen and Raloxifene (STAR) for the Prevention of Breast Cancer trial opened in 1999 to directly compare raloxifene to tamoxifen for breast cancer risk reduction. Since the unblinding of the STAR trial in 2006, raloxifene has emerged as an option for reducing breast cancer risk for postmenopausal women at increased risk for the disease.