Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-Related Cancer in Women: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.

Abstract

Importance\nPathogenic mutations in breast cancer susceptibility genes BRCA1 and BRCA2 increase risks for breast, ovarian, fallopian tube, and peritoneal cancer in women; interventions reduce risk in mutation carriers.\n\n\nObjective\nTo update the 2013 US Preventive Services Task Force review on benefits and harms of risk assessment, genetic counseling, and genetic testing for BRCA1/2-related cancer in women.\n\n\nData Sources\nCochrane libraries; MEDLINE, PsycINFO, EMBASE (January 1, 2013, to March 6, 2019, for updates; January 1, 1994, to March 6, 2019, for new key questions and populations); reference lists.\n\n\nStudy Selection\nDiscriminatory accuracy studies, randomized clinical trials (RCTs), and observational studies of women without recently diagnosed BRCA1/2-related cancer.\n\n\nData Extraction and Synthesis\nData on study methods, setting, population characteristics, eligibility criteria, interventions, numbers enrolled and lost to follow-up, outcome ascertainment, and results were abstracted. Two reviewers independently assessed study quality.\n\n\nMain Outcomes and Measures\nCancer incidence and mortality; discriminatory accuracy of risk assessment tools for BRCA1/2 mutations; benefits and harms of risk assessment, genetic counseling, genetic testing, and risk-reducing interventions.\n\n\nResults\nFor this review, 103 studies (110 articles; N\u2009=\u200992\u202f712) were included. No studies evaluated the effectiveness of risk assessment, genetic counseling, and genetic testing in reducing incidence and mortality of BRCA1/2-related cancer. Fourteen studies (n\u2009=\u200943\u202f813) of 8 risk assessment tools to guide referrals to genetic counseling demonstrated moderate to high accuracy (area under the receiver operating characteristic curve, 0.68-0.96). Twenty-eight studies (n\u2009=\u20098060) indicated that genetic counseling was associated with reduced breast cancer worry, anxiety, and depression; increased understanding of risk; and decreased intention for testing. Twenty studies (n\u2009=\u20094322) showed that breast cancer worry and anxiety were higher after testing for women with positive results and lower for others; understanding of risk was higher after testing. In 8 RCTs (n\u2009=\u200954\u202f651), tamoxifen (relative risk [RR], 0.69 [95% CI, 0.59-0.84]; 4 trials), raloxifene (RR, 0.44 [95% CI, 0.24-0.80]; 2 trials), and aromatase inhibitors (RR, 0.45 [95% CI, 0.26-0.70]; 2 trials) were associated with lower risks of invasive breast cancer compared with placebo; results were not specific to mutation carriers. Mastectomy was associated with 90% to 100% reduction in breast cancer incidence (6 studies; n\u2009=\u20092546) and 81% to 100% reduction in breast cancer mortality (1 study; n\u2009=\u2009639); oophorectomy was associated with 69% to 100% reduction in ovarian cancer (2 studies; n\u2009=\u20092108); complications were common with mastectomy.\n\n\nConclusions and Relevance\nAmong women without recently diagnosed BRCA1/2-related cancer, the benefits and harms of risk assessment, genetic counseling, and genetic testing to reduce cancer incidence and mortality have not been directly evaluated by current research.