Impact of age on racial disparity in early stage breast cancer in the United States.
e19058 Background: Racial disparities persists in women with early stage breast cancer and is most pronounced in Black (B) compared to White (W) women even when controlled for stage and biological subtype. Little is known about the impact of age on racial disparities. Our study evaluates the magnitude of a racial disparity in mortality across age strata in a real-world population. Methods: We identified stage I-III female breast cancer patients between 2010 – 2015 from the National Cancer Database. Hazard ratios (HR) and 95% Confidence Intervals (CI) for all-cause mortality were estimated using multivariable Cox Proportional Hazards regression, adjusted for clinical and demographic factors. The mortality risk for B and Other (O) race was compared to W across four age groups. To determine the significance in excess risk of mortality, the magnitude of disparity of each age group was compared to the > 60y age group. Results: A total of 679,327 patients were included. W comprised the largest percentage across all age groups. However, the percentage of W increased with age, while the percentage of B decreased with age (p < 0.001). The risk of mortality was significantly higher for B relative to W across all age groups ≤60y. When compared to > 60y, the magnitude of effect of age on risk of dying was significantly different (p < 0.0001) (Table). Conversely, the risk of mortality was significantly reduced for O race compared to W, with similar magnitude of effect across all ages. Conclusions: Even after adjusting for known risk factors of racial disparity such as insurance, biologic subtype and stage, the B to W racial disparity in mortality decreased with age (most pronounced in younger age) and appeared to diminish among women > 60 years of age. In contrast, the risk of dying in O race remained constant. Reasons are unclear and may be due to unmeasured socioecomomic or biologic factors that cannot be controlled for in this dataset. Regardless, identifying factors associated with worsened outcomes in younger age groups in B women should be the direction of future studies. [Table: see text]