- The U.S. Preventive Services Task Force (USPSTF) has added aromatase inhibitors (AIs) to the list of medications for reducing breast cancer risk in postmenopausal women.
- Tamoxifen is the only risk-reducing medication indicated for premenopausal women.
Why this matters
- A draft USPSTF report issued in January 2019 also featured the introduction of AIs but did not limit their use to postmenopausal women and did not specify tamoxifen as the only agent for premenopausal women. Previous guidance was issued in 2013.
- The USPSTF does not express a preference for which agents to use in postmenopausal women (AIs, raloxifene, or tamoxifen).
- All drugs on the list have "moderate" benefit.
- AIs decrease incidence of invasive breast cancer by 16 events per 1000 women over 5 years.
- Risk reduction with tamoxifen and raloxifene was 7 and 9 events per 1000 women over 5 years, respectively.
- AIs have "small to moderate harms" including hot flashes, musculoskeletal pain, gastrointestinal symptoms, and possible stroke or fracture.
- Raloxifene and tamoxifen have different harms, also "small to moderate."
- The new USPSTF report, like previous ones, does not specify a cutoff for increased risk for breast cancer but notes that women with ≥3% risk for breast cancer in the next 5 years are likely to experience more benefit than harm.
- A detailed evidence synthesis accompanies the USPSTF recommendation.