Racial disparities in survival after young-onset colorectal cancer.

Abstract

524 Background: Despite overall reductions in morbidity and mortality from colorectal cancer (CRC), racial disparities persist. In addition, incidence among individuals age <50 is rising. Our aim was to compare survival of young onset CRC cases diagnosed in black and white individuals. Methods: Using data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program we identified individuals with CRC between the ages of 20 to 49, diagnosed in 2000-2008. Kaplan-Meier and Cox proportional hazards models were used to compare stage-specific 5 year survival between black and white individuals with young onset CRC. Results: A total of 26,236 incident young onset CRC cases (22,121 white, 4,115 black) were identified during the 9 year study period. Overall survival at 5 years following CRC diagnosis was 54.8% among blacks and 67.4% among whites (p<0.001), with blacks having a significantly higher hazard of death after adjusting for age, sex, stage, tumor site, and treatment history (HR 1.34, 95% CI 1.26-1.43). Stratifying by stage at CRC diagnosis, blacks had worse survival at every disease stage compared with whites, with the greatest racial disparities observed among stage II cancers of colon (HR 1.68 95% CI 1.38-2.04) and stage II and III cancers of the rectum (HR 1.78, 95% CI 1.51-2.09, and HR 1.86, 95% CI 1.54-2.24, respectively). Conclusions: Survival after diagnosis of CRC at young age is significantly worse among blacks compared to whites, even among individuals with early stage disease. These findings suggest that differences in tumor biology may play a role in racial disparities in CRC outcomes, which may have implications for adjuvant treatment.