Prognosis after rectal cancer in blacks and whites participating in adjuvant therapy randomized trials

National health statistics indicate that blacks have lower survival rates from colorectal cancer than do whites. This disparity has been attributed to differences in stage at diagnosis and other disease features, extent and quality of treatment, and socioeconomic factors. We evaluated outcomes for blacks and whites with rectal cancer who participated in randomized clinical trials of the National Surgical Adjuvant Breast and Bowel Project (NSABP). The randomized trial setting enhances uniformity in disease stage and treatment plan among all participants.

The study included black (N = 104) or white (N = 1,070) patients from two serially conducted NSABP randomized trials for operable rectal cancer. Recurrence-free survival and survival were compared using statistical modeling to account for differences in patient and disease characteristics between the groups.

Blacks and whites had largely similar disease features at diagnosis. After adjustment for patient and tumor prognostic covariates, the black/white recurrence hazard ratio (HR) was 1.25 (95% confidence interval [CI], 0.94 to 1.66). The mortality HR was somewhat larger at 1.45 (95% CI = 1.09 to 1.93). Outcomes were improved for both groups in the more recent trial, which employed systemic adjuvant chemotherapy in all treatment arms.

Recurrence-free survival was modestly less favorable for blacks, whereas overall survival was more disparate. Outcomes between groups were more comparable than those noted in national health statistics surveys and other studies. Adequate treatment access and the identification of new prognostic factors that can identify patients at high risk of recurrence are needed to ensure optimal outcomes for rectal cancer patients of all racial/ethnic backgrounds.