Race and risk of subsequent aggressive breast cancer following ductal carcinoma in situ

BACKGROUND: General populations of black women have a higher risk of developing breast cancer negative for both estrogen receptor (ER) and progesterone receptor (PR) in comparison with white counterparts. Racial differences remain unknown in the risk of developing aggressive invasive breast cancer (IBC) that is characterized by negativity for both ER and PR (ER–PR–) or higher 21‐gene recurrence scores after ductal carcinoma in situ (DCIS). METHODS: This study identified 163,892 women (10.5% black, 9.8% Asian, and 8.6% Hispanic) with incident DCIS between 1990 and 2015 from the Surveillance, Epidemiology, and End Results data sets. Cox proportional hazards regression was used to estimate hazards ratios (HRs) of subsequent IBC classified by the hormone receptor status and 21‐gene recurrence scores. RESULTS: During a median follow‐up of 90 months, 8333 women developed IBC. In comparison with white women, the adjusted HR of subsequent ER–PR– breast cancer was 1.86 (95% confidence interval [CI], 1.57‐2.20) for black women (absolute 10‐year difference, 2.2%) and 1.40 (95% CI, 1.14‐1.71) for Asian women (absolute 10‐year difference, 0.4%); this was stronger than the associations for ER+ and/or PR+ subtypes (P (heterogeneity) = .0004). The 21‐gene recurrence scores of subsequent early‐stage, ER+ IBCs varied by race/ethnicity (P (heterogeneity) = .057); black women were more likely than white women to have a recurrence score of 26 or higher (HR, 1.38; 95% CI, 1.00‐1.92). No significant difference was observed in the risks of subsequent IBC subtypes for Hispanic women. CONCLUSIONS: Black and Asian women with DCIS had higher risks of developing biologically aggressive IBC than white counterparts. This should be considered in treatment decisions for black and Asian patients with DCIS.