Raloxifene, the generic name for the FDA-approved, brand-name, anti-osteoporosis medication, Evista. As one of a class of drugs known as selective estrogen receptor modulators (SERMs), Evista is used to increase bone density. The ability of raloxifene to bind to estrogen receptors on breast cells and to block the effects of estrogen on the breasts led to study of the potential of raloxifene for preventing breast cancer.
A recent clinical trial (called STAR), which was conducted by the National Surgical Adjuvant Breast and Bowel Project (NSABP) and sponsored by the National Cancer Institute (NCI), demonstrated that raloxifene is as effective as tamoxifen (brand name, Nolvadex) in reducing the risk of breast cancer in post-menopausal women at high risk (based on personal medical history and family history).
At entry into the trial, the estimated risk for participants to develop breast cancer in a 5-year period was 4% (which is higher than the 1.6 % risk for post-menopausal women lacking personal medical history and family history risk factors). Of the approximately 19,000 women who participated in the trial, roughly half received raloxifene for 5 years, whereas the other half received tamoxifen for 5 years. Either medication lowered the risk of breast cancer by approximately 50%.
The trial showed that raloxifene causes fewer serious side effects than does tamoxifen:[1, 2]
• Raloxifene treatment resulted in a 36% lower risk of the side effect of uterine cancer in women who had not had a hysterectomy than did tamoxifen treatment. Previous studies on raloxifene have not demonstrated an increase in cancer of the endometrium (the lining of the uterus).
• Raloxifene treatment resulted in nearly 30% less life-threatening blood clots (i.e., deep vein thrombosis and pulmonary emboli) in major vessels than did tamoxifen treatment.
• Raloxifene treatment resulted in 21% fewer cataracts and 18% fewer cataract surgeries than did tamoxifen treatment.
A similar incidence of coronary disease and bone fractures was observed in post-menopausal women treated with raloxifene or tamoxifen in the clinical trial.
Although raloxifene is FDA-approved for the prevention of osteoporosis, the FDA has not approved raloxifene yet for the prevention of invasive breast cancer in post-menopausal women.
1. National Cancer Institute. STAR results: Raloxifene as effective as tamoxifen, better safety profile. NCI Cancer Bulletin. 2006; 3(16):1-2. Accessed at www.cancer.gov.
2. T. H. Maugh II. Drug lowers cancer risk, side effects. Los Angeles Times. 04/18/06.