Prevalence of Advanced Colorectal Adenomas in Patients Undergoing Screening Colonoscopy in a Safety-net Hospital

Abstract

Introduction: Advanced colorectal adenomas are important precancerous lesions and include adenomas>9mm in size, tubulovillous histology, and high grade dysplasia. The aim of this study is to measure the prevalence of adenomas and advanced adenomas in patients undergoing screening colonoscopy, and to compare the prevalence in African Americans and other racial groups. Methods: We performed a retrospective analysis of all asymptomatic patients who underwent screening colonoscopy between July 1st 2009 and June 30th 2014. Patients with history of polyps, positive FOBT, diagnostic, or incomplete/inadequate colonoscopies were excluded. Data about patients' age, race, gender, quality of colon preparation, fellow participation (none, first, second, and third year), adenoma detection, size, location and histology were analyzed. Logistic regression was used to calculate the crude and adjusted odds ratios for the association of colonic findings with African Americans compared to other racial groups. Results: A total of 7171 screening colonoscopies were performed during the study period. 6448 patients (90%) had an adequate and complete examination, 632 patients (8.8%) had an inadequate/poor colon preparation, and 48 patients (0.7%) had failed cecal intubation. Among patients with adequate and complete examination, 2326 (36%) were men and 4122 (64%) women. Mean age was 58 years. The majority of patients were African Americans (n=5691, 88.4%), followed by white (n=334, 5.2%), Hispanic (n=213, 3.3%) and Asian (n=105, 1.6%). The overall prevalence of adenomas was 32.3%, and that of advanced adenomas was 8.3%. Overall, African Americans had similar rates of advanced adenomas compared to other racial groups (adjusted OR 1.15, 95% CI 0.9-1.5). There was a higher rate of high grade dysplasia/ cancer in African Americans compared with other racial groups (1.4% Vs. 0.5%, adjusted OR 2.9, 95% CI 1.1-8). Rates of nonadvanced adenomas, adenomas>9mm, and adenomas with tubulovillous histology were similar among both groups (table 1). The distribution of adenomas in the proximal and distal colon was similar in both groups. Conclusion: The overall prevalence of advanced adenomas was similar between African Americans and other racial groups. However, the prevalence of adenomas with dysplasia/cancer was significantly higher in African Americans. This supports the need for special efforts to improve colorectal cancer screening participation rates in African Americans.Table 1: Prevalence of advanced adenomas among African Americans and other racial groups