Common Questions
How does raloxifene affect the risk of invasive breast cancer?
The RUTH (Raloxifene Use for The Heart) trial found that raloxifene reduced the risk of invasive breast cancer by 44% (primarily estrogen receptor positive tumors) (1). This was a randomized, placebo-controlled trial of over 10,000 postmenopausal women that received either placebo or raloxifene (60 mg/day) and were followed for 5 to 6 years. The two primary outcomes were invasive breast cancer and coronary artery events. The absolute risk reduction was 1.2 invasive breast cancers per 1000 women treated for one year.
A head to head study of raloxifene and tamoxifen, a SERM that has been shown to reduce the incidence of invasive breast cancer by over 50%, was conducted to evaluate their effects on the incidence of breast cancer. The Study of Tamoxifen and Raloxifene (STAR) was a multicenter, double blind, randomized trial of over 19,000 postmenopausal women at increased risk for breast cancer. It found that raloxifene (60 mg/day) was just as effective as tamoxifen (20 mg/day) in lowering the risk of invasive breast cancer (2). There were more cases of noninvasive breast cancer in the raloxifene group as compared with the tamoxifen group, but the difference was not statistically significant.
Fig. 1 Cumulative Incidence of Invasive and Noninvasive Breast Cancer
Copyright 2006, American Medical Association
- Barrett-Connor E, Mosca L, Collins P, et al., for the Raloxifene Use for The Heart (RUTH) Trial Investigators.. Effects of raloxifene on cardiovascular events and breast cancer in postmenopausal women. N Engl J Med 2006; 355: 125-137.
- Vogel VG, Costantino JP, Wickerham DL, Cronin WM, Cecchini RS, et al. for the National Surgical Adjuvant Breast and Bowel Project (NSABP). Effects of tamoxifen vs raloxifene on the risk of developing invasive breast cancer and other disease outcomes. The NSABP Study of Tamoxifen and raloxifene (STAR) P-2 Trial. JAMA 2006; 295: 2727-2741.