Underutilization of BRCA1/2 testing to guide breast cancer treatment: black and Hispanic women particularly at risk

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.

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.

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.

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.