USPSTF Recommends Primary Breast Cancer Preventive Medications for High-Risk Women

By Will Boggs MD

September 04, 2019

NEW YORK (Reuters Health) - Clinicians should offer risk-reducing medications to women who are at increased risk for primary breast cancer, according to an updated recommendation statement from the United States Preventive Services Task Force (USPSTF).

"Women who have a greater risk of developing breast cancer stand to benefit the most from these risk-reducing medications; meanwhile, women who are not at increased risk are more likely to experience harms than benefits," USPSTF Task Force member Dr. Michael Barry from Harvard Medical School, Boston, told Reuters Health by email. "The Task Force encourages women to talk about the benefits and harms of medication with their clinicians so they can make the best choice for themselves, based on their personal values and preferences."

Dr. Barry and colleagues on the USPSTF updated the 2013 recommendations based on an updated evidence report and systematic review of 46 studies covering more than 5 million participants.

The 2019 statement reiterates the 2013 recommendation to offer risk-reducing medications to women at increased risk for breast cancer and at low risk for adverse medication effects as well as the recommendation against routine use of risk-reducing medications in women not at increased risk.

Unlike the 2013 guidance, the current statement now includes aromatase inhibitors among the medications that can reduce the risk of breast cancer, along with tamoxifen and raloxifene.

The statement stopped short of endorsing any particular risk prediction tool, but mentioned the National Cancer Institute Breast Cancer Risk Assessment Tool and the Breast Cancer Surveillance Consortium Risk Calculator as useful resources that have been tested in US populations and are publicly available "for clinicians and patients to use as part of the process of shared, informed decision-making about taking risk-reducing medications for breast cancer."

While there is no single cutoff for defining increased risk for asymptomatic women, those with at least a 3% risk for breast cancer in the next 5 years are likely to derive more benefit than harm from these medications.

The USPSTF found insufficient evidence on the benefits and harms of risk-reducing medications in women with BRCA1/2 gene mutations or women with a history of chest radiation.

Women not at increased risk for breast cancer (those younger than 60 years with no additional risk factors for breast cancer or women with a low 5-year risk of breast cancer, for example) should not be routinely offered medications to reduce their risk of breast cancer, because the risk of harms from these medications (such as venous thromboembolic events, endometrial cancer, and cataracts) likely outweighs their potential benefit, according to the USPSTF recommendation.

"The Task Force has also identified a need for more research to better understand how to identify women at increased risk for breast cancer who may benefit from these risk-reducing measures," Dr. Barry said. "Additionally, we also need more evidence to better understand the lifelong benefits and harms of these medications and how they can reduce risk in specific populations, such as African-American women who are more likely to die of breast cancer, and women who carry harmful BRCA gene mutations."

Dr. Heidi D. Nelson from Oregon Health and Science University, Portland, Oregon, who co-authored the updated evidence report and systematic review, told Reuters Health by email, "Despite much research on methods to predict a woman's risk of breast cancer, evaluations of 18 risk assessment methods indicate that they are inaccurate. Most methods perform only slightly better than age alone as a risk predictor. Consequently, current practices of selecting women for risk-reducing medications using available methods, including the modified 5-year Gail score, are also likely inaccurate."

"Various risk criteria were used to enroll women into trials of risk-reducing medications," she said. "These criteria usually included family history of breast cancer and previous benign breast biopsy, particularly atypical hyperplasia. Results of the trials may be most applicable to women with similar risks as the trial participants."

Dr. Lydia E. Pace from Brigham and Women's Hospital, Boston, Massachusetts, who co-authored an editorial related to this report, told Reuters Health in an email, "I have cared for patients who do really well with risk-reducing medications and feel good about their decision to take them. I have other patients who have not tolerated them and need to stop after a short time. And I've had patients who strongly don't want to take a new medication every day for 5 years and don't feel the potential benefit is worth it."

"Decisions about these medications are often not clear-cut and I try to convey that, as long as women are informed, all of these decisions are okay," she said. "Hopefully, we will have a growing array of options for reducing risk that have fewer downsides. It's also important for women to remember that there are other important ways that they can reduce breast cancer risk, including reducing alcohol intake and maintaining a healthy weight."

The complete recommendation statement, evidence review, editorials, and patient page appear in the September 3rd JAMA.

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JAMA 2019.