The United States Preventive Services Task Force (USPSTF) recommends against using medications such as tamoxifen or raloxifene for reducing the risk of primary breast cancer in average risk women, as the risks associated with these medications outweigh the potential benefits.
Doctors should discuss the benefits and harms of these treatments and offer to prescribe them to women who are at high risk for breast cancer and low risk for adverse reactions. In high-risk populations, the benefits may outweigh the risks.
This recommendation reaffirms the Task Force's 2002 recommendation and provides updated evidence on the risks and benefits of risk-reducing medications for women who are at increased risk for breast cancer. To update its previous recommendations, the Task Force reviewed evidence published through December 2012.
In placebo-controlled trials, both tamoxifen and raloxifene reduced the incidence of invasive breast cancer over the five-year treatment period, and both medications reduced fractures. In head-to-head trials, tamoxifen had greater effect at reducing invasive breast cancer than raloxifene, but also was associated with more thromboembolic events, endometrial cancer, and related gynecologic outcomes and cataracts compared with placebo and raloxifene.
Using Medications to Decrease the Risk for Breast Cancer in Women: Recommendations from the U.S. Preventive Services Task Force, Ann Intern Med. Published online 24 September 2013 doi:10.7326/0003-4819-159-10-201311190-00717