601 Advanced Neoplasia of the Left Hemicolon Are Better Detected By Fit Than Right Sided Lesions

Abstract

Traditionally, hyperplastic polyps of the colon were considered to be innocent lesions, with no malignant potential. However, the recently discovered alternative serrated pathway to colorectal cancer (CRC) suggests that at least some of these polyps are potential precursors for CRC. The aims of this study were i) to investigate the relation between hyperplastic polyps and the development of CRC and ii) to analyze the predictors for colorectal cancer in patients with hyperplastic polyps. Patients were retrospectively selected using a national pathology database (PALGA). Between 1991-1998, 943 hyperplastic polyps were detected in 568 patients undergoing diagnostic colonoscopy at our university hospital. Endoscopical data regarding number, size and location of the polyps at the index-colonoscopy were recorded. Endpoints were CRC, last colonoscopy or death. Outcome data were available using the registration database of the Regional Comprehensive Cancer Center. Kaplan-Meyer analysis was used to calculate the risk of CRC in patients with hyperplastic polyps. Results: A total of 568 patients were included (mean (SEM) age: 60 (+/1) years, 57% males), 410 patients with hyperplastic polyps only and 158 patients with hyperplastic polyps and also adenomas. Prevalence of CRC was 3.5% during a median follow-up period of 11 years (20 CRC cases), in line with prevalence of CRC in the general Dutch population. CRCs tended to be more frequently located in the right colon compared to the left colon (2.5% versus 1.1%, p=0.074). Multivariate analysis showed that presence of multiple hyperplastic polyps (hazard ratio 2.7, 95% CI 1.1 6.9; p=0.043), as well as presence of large (> 5 mm) hyperplastic polyps in the right colon (hazard ratio 7.8, 95% CI 3.0 20.5 p < 0.0001) were independent risk factors for the development of CRC. The concomitant presence of adenomas was not an additional risk factor for the development of CRC. Conclusion: Patients with large, right-sided hyperplastic polyps have nearly 8-fold increased risk for development of colorectal cancer. These data reinforce the potential role of the serrated pathway in the pathogenesis of CRC. As surveillance of patients with high-risk hyperplastic polyps remains controversial, development of guidelines is indicated.