Trends in BRCA Test Utilization in an Integrated Health System, 2005-2015.

Background: Genetic testing to determine BRCA status has been available for over two decades, but there are few population-based studies of test diffusion. We report ten-year trends in BRCA testing in an integrated health care system with longstanding access to genetic services.

Methods: A cohort of women aged 18 years and older was created to ascertain BRCA testing (n = 295,087). Annual testing rates between 2005 and 2015 were calculated in all women with and without incident (i.e., newly diagnosed) breast and ovarian cancers and in clinically eligible subgroups by family cancer history, personal cancer history, and age at diagnosis. Secular trends were assessed using Poisson regression. Women tested early (2005-2008), midway (2009-2012), and late (2013-2015) in the study period were compared in cross-sectional analyses.

Results: Between 2005 and 2015, annual testing rates increased from 0.6/1,000 person years (pys) (95% confidence interval [CI]: 0.4 to 0.7/1,000 pys) to 0.8/1,000 pys (95% CI: 0.6 to 1.0/1,000 pys) in women without incident breast or ovarian cancers. Rates decreased from 71.5/1,000 pys (95% CI: 42.4 to 120.8/1,000 pys) to 44.4/1,000 pys (95% CI: 35.5 to 55.6/1,000 pys) in women with incident diagnoses, despite improvements in provision of timely BRCA testing during this timeframe. We found no evidence of secular trends in clinically eligible subgroups including women with family history indicating increased hereditary cancer risk, but no personal cancer history. At the end of the study period, 97.0% (95% CI = 96.6% to 97.3%) of these women remained untested.

Conclusion: Many eligible women did not receive BRCA testing despite having insurance coverage and access to specialty genetic services, underscoring challenges to primary and secondary hereditary cancer prevention.