The US Preventive Services Task Force (USPSTF) recently released updated recommendations regarding use of medications that reduce a woman’s risk of developing breast cancer. The recommendation suggests that clinicians offer these medications to individuals at increased risk for breast cancer but low risk of experiencing adverse side effects.

In an editorial in JAMA, assistant professor of medicine Lydia Pace, MD, MPH, and professor of health care policy and medicine Nancy L. Keating, MD, MPH, highlight the difficulty of identifying a high risk patient who is unlikely to experience negative side effects.  

Drugs such as tamoxifen, raloxifene, anastrozole, and exemestane reduce the risk of developing breast cancer in high-risk patients by around 50%. These benefits appear persistent for more than 10 years after initiation of treatment; however the absolute benefit is relatively small, and these drugs do not lower the risk of dying of breast cancer. It is important to balance this benefit with the harms of these medications, including the possibility of developing venous thromboembolism, endometrial cancer, and menopausal and musculoskeletal symptoms can make patients reluctant to initiate or continue treatment.

Pace and Keating suggest that discussions of breast cancer risk and treatment preferences become a more prominent part of women’s primary care. While studies of risk-reducing medications included women with a 5-year risk higher than 1.66%, the authors believe that consideration for patients with a 5-year risk of breast cancer greater than 3% may be more reasonable. Research into safer and more effective preventative medications may improve the balance of benefits and harms for risk reducing medications.