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J Natl Cancer Inst 2008;100:854–61.
Editor’s note: Chemoprevention with antiestrogens appears to be effective at reducing the risk of breast cancer. In a large placebo-controlled trial conducted by the National Surgical Adjuvant Breast and Bowel Project (NSABP P-1), treatment with tamoxifen reduced the incidence of invasive breast cancer by 49% (
J Natl Cancer Inst 1998;90:1371–88). However, the use of tamoxifen has been associated with increased risk of uterine cancer, stroke, and venous thromboembolism in postmenopausal women. Therefore, new, effective, and safer approaches for the prevention of breast cancer would be welcome. Two major clinical trials have provided evidence that the selective estrogen receptor (ER) modulator raloxifene is a promising drug for the prevention of breast cancer. In the MORE (Multiple Outcomes of Raloxifene Evaluation) trial, postmenopausal women with osteoporosis treated for 4 years with raloxifene had a 72% reduction in the incidence of invasive breast cancer compared with women treated with placebo (
Breast Cancer Res Treat 2001;65:125–34). The protective effect of raloxifene against breast cancer persisted over 8 years of follow-up (
J Natl Cancer Inst 2004;96:1751–61). More recently, the main results of the RUTH (Raloxifene Use for the Heart) trial were published, including information on the effects of raloxifene on invasive and non-invasive breast cancer (
N Engl J Med 2006;355:125–37). The present report provides additional data from the RUTH trial, including the effects of raloxifene on the risk of breast cancer by histological time, tumor stage, lymph node status, and tumor grade and size, as well as by duration of treatment and subgroup.