Abstract
PURPOSE: To effectively reduce cancer burden, genetic testing programs should identify high-risk individuals prior to cancer development, when risk-reduction strategies can be implemented. We evaluated trends in BRCA1/BRCA2 testing use after implementation of a publicly funded testing program. METHODS: We conducted a retrospective, near population-based study of women who underwent BRCA1/BRCA2 testing in Ontario, Canada, (2007-2016) (n = 15,986). Temporal trends were evaluated using linear and Poisson regression. RESULTS: Although annual utilization of testing increased over time (p < 0.001), mean age at testing increased from 49.9 years (SD 13.8) in 2007 to 53.8 years (SD 13.7) in 2016 (p < 0.001). The proportion of women with a cancer history at testing also increased from 53.5% in 2007 to 66.3% in 2015 (p < 0.001); the proportion of women free from breast cancer did not change significantly (49.2% in 2007 versus 45.1% in 2015, p = 0.90). As a proportion of all tested, those with breast cancer tested within 3 months of diagnosis increased over time (0.39% of tests in 2007 versus 13.6% of tests in 2015; p < 0.001). CONCLUSIONS: While the institution of a publicly funded genetic testing program was associated with rising utilization, increasing age at testing and decreasing testing of unaffected women suggest limitations in identifying high-risk individuals eligible for risk-reduction.