Osteoporosis Drug as Effective as Tamoxifen in Preventing Invasive Breast Cancer: Initial Results Include Yale Cancer Center Patients
Initial results of the Study of Tamoxifen and Raloxifene (STAR), in which Yale Cancer Center participated, show that the drug raloxifene, currently used to prevent and treat osteoporosis in postmenopausal women, works as well as tamoxifen in reducing breast cancer risk for postmenopausal women at increased risk of the disease.
In STAR, one of the largest breast cancer prevention trials ever conducted, both drugs reduced the risk of developing invasive breast cancer by about 50 percent. In addition, women who were prospectively and randomly assigned to take raloxifene daily, and who were followed for an average of four years, had 36 percent fewer uterine cancers and 29 percent fewer blood clots than the women who were assigned to take tamoxifen. Uterine cancers, especially endometrial cancers, are a rare but serious side effect of tamoxifen. Both tamoxifen and raloxifene are known to increase a woman’s risk of blood clots.
Coordinated by the National Surgical Adjuvant Breast and Bowel Project (NSABP), a network of cancer research professionals, the trial is sponsored by the National Cancer Institute (NCI), part of the National Institutes of Health. STAR enrolled 19,747 postmenopausal women who were at increased risk of the disease. Participants were randomly assigned to receive either 60 mg of raloxifene (Evista®) or 20 mg of tamoxifen (Nolvadex®) daily for five years. In Connecticut, 307 women were enrolled including 55 women at the Yale Cancer Center.
“Results of the STAR trial will have a great impact on the treatment of many women with breast cancer. Raloxifene (Evista) was as effective as Tamoxifen at reducing the incidence of invasive breast cancer, and had fewer side effects. For most post-menopausal women at high risk, Raloxifene will probably be the current drug of choice for prevention of breast cancer,” said Donald Lannin, M.D., principal investigator of the STAR trial at Yale Cancer Center and executive director of the Yale-New Haven Breast Center. “We are hoping that future trials will identify even more effective cancer treatments.”
Women taking either drug had equivalent numbers of strokes, heart attacks and bone fractures. Both raloxifene and tamoxifen are known to protect bone health; it is estimated that half a million postmenopausal women are currently taking raloxifene by prescription to prevent or treat osteoporosis. Additionally, the initial results from STAR suggest that raloxifene does not increase the risk of developing a cataract, as tamoxifen does.
“Although no drugs are without side effects, tamoxifen and raloxifene are vital options for women who are at increased risk of breast cancer and want to take action,” said Leslie Ford, M.D., associate director for clinical research in NCI’s Division of Cancer Prevention. “For many women, raloxifene’s benefits will outweigh its risks in a way that tamoxifen’s benefits do not.”
For more information about STAR, including links to media materials and a fact sheet, visit NCI’s STAR home page at http://www.cancer.gov/star or one of NSABP’s Web sites at http://www.nsabp.pitt.edu and http://foundation.nsabp.org. For tools used to calculate a woman’s risk of breast cancer, visit http://cancer.gov/bcrisktool or http://breastcancerprevention.com.
For a Q&A related to the STAR results, go to the National Cancer Institute web site.