Colon Polyp Distribution and Risk Stratification

Abstract

Introduction: Colon cancer screening using colonoscopy was reported to have less impact in reducing right-sided colon cancer. We postulate that many right colon adenomas may have been missed during the screening process due to lack of attention. By increasing the withdraw time to pay more attention to identify adenomatous polyps, we have found far more colon adenomas in the right colon than the left colon. By focusing more effort to identify and remove polyps in the right colon, the colon cancer risk reduction should be the same between the right and left colon cancer. The future risk of colon cancer can be drastically reduced by changing our focus during routine screening colonoscopy.Table: Table. Demographics of PatientsMethods: Colonoscopy reports and pathology reports were collected and reviewed to tabulate withdraw time and adenoma detection rate since 2010. Many variables were included in the data collection including age, sex, indication, insertion time, withdraw time, etc. By 2012, we have expanded our data collection to include adenoma tissue types and location in the colon. A dedicated staff member was responsible for data entry into a Microsoft Excel spreadsheet. The graphs of this study were generated using Microsoft Excel. The statistical analysis were performed using R and Matlab. Results: Between 2012 and 2017, we have performed 10932 colonoscopies. Within this group, 6938 colonoscopies reported adenoma removal {adenoma detection rate (ADR) = 63.46%}. The distributions of the colon polyps are very different between regions of the colon (Figure #1). Significantly more adenomas were found in the ascending colon, cecum, and transverse colon (right colon) compared to the rectum, sigmoid colon, and descending colon (left colon). The ratio is 87.48% right colon adenoma versus 12.52% left colon adenoma (p < 0.00001). The difference between right and left colon adenoma is more than six fold. Tubular adenoma was the predominant type of polyp found. The average withdraw time was 22.5 minutes in our study group.Figure: Adenoma Distribution within the Colon.Conclusion: Colonoscopy is an excellent tool to reduce the risk of colon cancer. In order to make it more effective, we need to pay more attention and time to identify and remove the right colon polyps. The risk of right-sided colon polyp/adenoma is more than six fold than the left-sided colon polyp/adenoma. Furthermore, using this information we can more accurately stratify the risk of these patients to make appropriate recommendations for future screening.