Is BRCA testing causing women to undergo unnecessary prophylactic mastectomy?

Because the prevalence of BRCA1 and BRCA2 mutations is elevated among young women diagnosed with breast cancer, guidelines recommend carrier testing for women diagnosed with this disease at age 50 years or younger.¹ Are women being tested, however, and what are their treatment decisions surrounding those test results? The Young Women’s Breast Cancer Study (YWBCS) seeks to answer such questions.

Details of the study
Study investigators recruited women diagnosed with breast cancer at age 40 or younger from 11 academic and community hospitals in the United States and Canada beginning in 2006. There were 897 evaluable participants who were recruited between 2006 and 2014. Their mean age at diagnosis was 35.5 years and 86.1% of them were white non-Hispanic. A respective 84.5% and 99.8% of women had at least a college education and were insured.

Overall, BRCA testing was performed within 1 year of breast cancer diagnosis in 87% of participants, with rates rising from 77% in 2006 to 95% in 2013. Among participants tested, 7.6% had a BRCA1 mutation, 4.5% had a BRCA2 mutation, 4.6% had an indeterminate result of unknown clinical significance, and 81.3% had a negative test result.

A total of 86.4% of women found to be mutation carriers proceeded with risk-reducing bilateral mastectomy; 51.2% found not to be mutation carriers had this same prophylactic surgery.

What this evidence means for practice
Although it is encouraging to see that the proportion of young women with breast cancer who are receiving counseling and genetic testing is rising, the findings from this study of highly educated, largely white and affluent women is not generalizable to all US women diagnosed with breast cancer at a young age.
That more than half of BRCA-negative women in this study chose bilateral prophylactic mastectomy, a procedure not recommended in this population, is concerning, and reflects nationwide trends.² The increasing use of next-generation sequencing (which yields information on moderate- and low-penetrance genes in addition to BRCA status) means that women and their providers increasingly are being confronted with genetic testing results that call for formal genetics expertise. Unfortunately, genetics counselors remain in short supply and many clinicians without specific genetics training are offering these tests. As editorialists appropriately point out, these trends may further increase the number of relatively low-risk women proceeding with unwarranted bilateral mastectomy.³ In my practice, I continue to refer women whose family or personal histories indicate high-risk status to a cancer genetics counselor for formal counseling and possible testing.
—Andrew M. Kaunitz, MD

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