In a statement published in JAMA, the U.S. Preventive Services Task Force (USPSTF) recommended that clinicians offer to prescribe risk-reducing medications to women who are at an increased risk of breast cancer and at low risk of adverse events related to medications. However, the Task Force recommended against the routine use of risk-reducing medications in women who are not at an increased risk of breast cancer. This statement reaffirms the 2013 USPSTF recommendation on drug use to reduce breast cancer risk.

The USPSTF reviewed evidence from randomized trials and observational/diagnostic accuracy studies on the accuracy of risk-assessment methods to identify women who could benefit from breast cancer risk-reducing medications. It also reviewed evidence on the effectiveness, adverse effects, and subgroup variations of the risk-reducing medications.

Determinations

The Task Force found evidence that risk-assessment tools can predict the number of breast cancer cases expected to develop within a population. However, the same tools perform “modestly at best” in predicting whether an individual woman will or will not develop breast cancer.

The USPSTF panel of experts also found evidence that the risk-reducing medications tamoxifen, raloxifene, or aromatase inhibitors provide at least a moderate benefit in reducing the risk of developing invasive estrogen receptor–positive breast cancer in postmenopausal women who are at an increased risk for the disease. However, the benefits of taking these medications to reduce the risk of breast cancer are no greater than small in women who are not at an increased risk of the disease, according to the USPSTF.

The Task Force also found convincing evidence that taking tamoxifen and raloxifene to reduce the risk of breast cancer is associated with small to moderate harms. The panel found adequate evidence that taking aromatase inhibitors is associated with small to moderate harms.

The recommendation concludes, “Overall, the USPSTF determined that the net benefit of taking medications to reduce risk of breast cancer is larger in women who have a greater risk for developing breast cancer. The USPSTF recommends that clinicians offer to prescribe risk-reducing medications, such as tamoxifen, raloxifene, or aromatase inhibitors, to women who are at increased risk for breast cancer and at low risk for adverse medication effects (B recommendation). The USPSTF recommends against the routine use of risk-reducing medications, such as tamoxifen, raloxifene, or aromatase inhibitors in women who are not at increased risk for breast cancer (D recommendation). This recommendation applies to asymptomatic women 35 years and older, including women with previous benign breast lesions on biopsy (such as atypical ductal or lobular hyperplasia and lobular carcinoma in situ). This recommendation does not apply to women who have a current or previous diagnosis of breast cancer or ductal carcinoma in situ.”

Disclosure: For full disclosures of the study authors, visit jamanetwork.com.