Higher prevalence of proximal colon polyps and villous histology in African-Americans undergoing colonoscopy at a single equal access center

Background: In the United States, African Americans (AA) have the highest incidence and mortality from colorectal cancer (CRC) of any racial group. Few studies have evaluated if AA who undergo colonoscopy are more likely to have aggressive neoplasia (polyp) tumor biology compared to Caucasians (C). The primary aim of the study was to compare polyp characteristics between AA and C undergoing outpatient colonoscopy. Methods: A single center retrospective cohort study was performed at a single Veteran Administration (VA) health care system. The charts of 4,038 veterans undergoing colonoscopy from 2005 to 2008 were reviewed. After applying exclusion criteria, data was analyzed for 1,388 persons. Categorical variables were compared using the chi-square test and data were expressed as percentages. Continuous variables were compared using student's t-test and the data were expressed as mean with standard deviation. Results: A total of 37% of AA had proximal polyps compared to 21% of C (P<0.0001). Twenty-four percent of AA had polyps with villous histology compared to 16% of C (P=0.01). Twelve percent of AA had hyperplastic polyps compared to 20% of C (P=0.02). There was no difference in the overall prevalence of tubular adenomas, adenomatous polyps with high-grade dysplasia, number, size or polyp morphology between groups. Conclusions: In an equal access healthcare system and under varying indications, AA have more proximal polyps and polyps with more aggressive histology compared to C. This could partially explain the higher incidence of CRC in AA, and the increased likelihood for AA to develop advanced proximal neoplasia.