Purpose: We retrospectively investigated the impact of race/ethnicity on prognosis in patients who underwent surgery for colon cancer.
Methods: Surveillance, Epidemiology, and End Results population-based data on 39,210 colon cancer patients without distant metastasis who underwent radical surgery were analyzed. Prognostic impact of race/ethnicity for non-Hispanic white, Hispanic white, African American, and East Asian (Japanese, Chinese, Korean) American patients, and confounding factors of age, sex, registry region, year of diagnosis, tumor, node, metastasis system stage, tumor grade, tumor site, and the number of lymph nodes examined were analyzed by the Cox proportional hazard model. The lymph node count was analyzed and adjusted means were calculated by a generalized multiple regression model with respect to race and other factors.
Results: Significant differences due to race/ethnicity were observed in crude hazard ratios with respect to overall and colon cancer-specific mortality, which persisted even after adjusting for confounding factors. Adjusted hazard ratios of colon cancer-specific mortality for non-Hispanic white, Hispanic white, African American, and East Asian American patients were 1 (reference), 1.01 (95% confidence interval 0.91-1.12), 1.40 (95% confidence interval 1.31-1.50), and 0.83 (95% confidence interval 0.74-0.94), respectively. There were significant differences in crude number of lymph nodes examined among races, which were no longer significant after adjusting for covariates.
Conclusions: East Asian American patients had significantly better prognosis, while African American patients had worse prognosis than non-Hispanic white patients, despite the identical adjusted number of lymph nodes examined after surgery for colon cancer. This disparity in prognosis among races/ethnicities should be taken into consideration when deciding adjuvant chemotherapy for nonwhite patients.