Anatomic site distribution of colon cancer by race and other colon cancer risk factors

Black patients with colon cancer are more likely to have poorer survival from colon cancer than are white patients. To determine whether anatomic site differences might contribute to survival differences, we compared anatomic site distributions of black and white patients. As part of the Black/White Cancer Survival Study, we collected medical record data for 1,045 patients from Atlanta, New Orleans, and San Francisco/Oakland, newly diagnosed in 1985 or 1986 and interviewed 745 of them. In polychotomous logistic regression analysis, site was related to stage, grade, and histologic type and among women with age, parity, and possibly smoking. However, it was not related to race, except perhaps among men age 65 and older, among whom blacks were somewhat likely to have more transverse and distal, not proximal, cancer. These relations were consistent across subgroups and were independent of other factors examined. Results suggest that site differences are unlikely to contribute to poorer survival commonly observed among black colon cancer patients in the United States.