Purpose: Women with early-onset (age ≤40 years) breast cancer are at high risk of carrying deleterious mutations in the BRCA1/2 genes; genetic assessment is thus recommended. Knowledge of BRCA1/2 mutation status is useful in guiding treatment decisions. To date, there has been no national study of BRCA1/2 testing among newly diagnosed women.
Methods: We used administrative data (2004-2007) from a national sample of 14.4 million commercially insured patients to identify newly diagnosed, early-onset breast cancer cases among women aged 20-40 years (n = 1474). Cox models assessed BRCA1/2 testing, adjusting for covariates and differential lengths of follow-up.
Results: Overall, 30% of women aged 40 years or younger received BRCA1/2 testing. In adjusted analyses, women of Jewish ethnicity were significantly more likely to be tested (hazard ratio = 2.83, 95% confidence interval: 1.52-5.28), whereas black women (hazard ratio = 0.34, 95% 0.18-0.64) and Hispanic women (hazard ratio = 0.52, 95% confidence interval: 0.33-0.81) were significantly less likely to be tested than non-Jewish white women. Those enrolled in a health maintenance organization (hazard ratio = 0.73, 95% confidence interval: 0.54-0.99) were significantly less likely to receive BRCA1/2 testing than those point of service insurance plans. Testing rates increased sharply for women diagnosed in 2007 compared with 2004.
Conclusions: In this national sample of patients with newly diagnosed breast cancer at high risk for BRCA1/2 mutations, genetic assessment was low, with marked racial differences in testing.