Weighing the Risks and Benefits of Tamoxifen and Raloxifene for Breast Cancer Prevention

Researchers have developed a tool that can help guide decisions about which drug—tamoxifen or raloxifene (EvistaR)—is the best choice for breast cancer prevention in high-risk postmenopausal women. These results were published in the Journal of Clinical Oncology.???

Drugs that block the effects of estrogen have been shown to reduce the risk of breast cancer in women at high risk of the disease. Two drugs that have been approved for breast cancer risk reduction in certain groups of women are tamoxifen and raloxifene. Tamoxifen is approved for breast cancer risk reduction in women who are at high risk of the disease (including high-risk premenopausal women). Raloxifene—originally approved for the prevention and treatment of osteoporosis—is approved for breast cancer risk reduction in postmenopausal women with osteoporosis or postmenopausal women at high risk of breast cancer.??

To help postmenopausal women and their healthcare providers evaluate the likely effect of each drug, researchers developed a benefit-risk index. In addition to considering the extent to which each drug reduced breast cancer risk, the researchers also assessed other health outcomes, such as bone fractures, blood clots, stroke, and endometrial (uterine) cancer.???

The researchers found that the risks and benefits of tamoxifen and raloxifene vary by a woman’s age, race/ethnicity, risk of breast cancer, and whether the woman has had a hysterectomy.????

The researchers write “By combining this information with information on clinical features and personal preferences, the health care provider and patient can make an informed decision.” The researchers provide tables to help specific subgroups of women evaluate the likely benefit (or harm) of each drug.?

Women who have a high risk of breast cancer as a result of their family or personal medical history may wish to talk with their doctor about ways to reduce their cancer risk.?

Reference: Freedman AN, Yu B, Gail MG et al. Benefit/risk assessment for breast cancer chemoprevention with raloxifene or tamoxifen for women age 50 years or older. Journal of Clinical Oncology. Early online publication May 2, 2011.?

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