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The U.S. Preventive Services Task Force today recommended that clinicians offer breast cancer risk-reducing medications such as tamoxifen, raloxifene and aromatase inhibitors to asymptomatic women aged 35 years and older who are at elevated risk for developing the disease and low risk for adverse effects from the treatments.
This recommendation received a B grade. The task force also recommended against, with a D grade, use of such medicines among women not at high risk for breast cancer.
“There are medications available that can help some women prevent breast cancer, but they are not for everyone,” USPSTF member Michael J. Barry, MD, director of the Informed Medical Decisions Program at Massachusetts General Hospital and professor of medicine at Harvard Medical School, said in a press release. “For women who are at increased risk for breast cancer, these medications can be beneficial and reduce their risk.”
statement, published simultaneously with an evidence report in JAMA, serves as an update to the 2013 USPSTF recommendation on medications for women to reduce their risk for primary invasive breast cancer.
Investigators for the task force reviewed reference lists in the Cochrane Central Register of Controlled Trials and Database of Systematic Reviews, EMBASE and MEDLINE between Jan. 1, 2013, and Feb. 1, 2019, and selected discriminatory accuracy studies of breast cancer risk evaluation methods; randomized clinical trials of tamoxifen, raloxifene and aromatase inhibitors for the prevention of primary breast cancer; and studies addressing adverse effects of the medications. They gathered data on methods, participant traits, inclusion criteria, outcome determination and follow-up, and pooled results of the individual trials using a random-effects model.
among individuals; incidence of breast cancer, fractures, thromboembolic events, coronary disease events, stroke, endometrial cancer and cataracts; and mortality served as the main outcomes.
The analysis included 46 studies involving more than 5 million participants. In 25 studies, 18 methods of risk assessment demonstrated low accuracy in predicting breast cancer likelihood among individuals (area under the curve, 0.55-0.65).
Results of placebo-controlled trials showed an association between the following medications and decreased incidence of invasive breast cancer: tamoxifen (risk ratio [RR] = 0.69; 95% CI, 0.59-0,84; four trials; n = 28,421); raloxifene (RR = 0.44; 95% CI, 0.24-0.8; two trials; n = 17,806); and the aromatase inhibitors exemestane and anastrozole (RR = 0.45; 95% CI, 0.26-0.7; two trials; n = 8,424).
One trial reported a higher risk for invasive breast cancer with raloxifene vs. tamoxifen after long-term follow-up (RR = 1.24; 95% CI, 1.05-1.47; n = 19,747), whereas two trials (n = 16,929) showed a lower risk for vertebral fractures with raloxifene (RR = 0.61; 95% CI, 0.53-0.73). One trial (n = 13,388) reported lower risk for nonvertebral fractures with tamoxifen vs. placebo (RR = 0.66; 95% CI, 0.45-0.98).
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