Individuals With Sessile Serrated Polyps Express an Aggressive Colorectal Phenotype

Abstract

Sessile serrated polyps are precursors of colorectal cancer arising from molecular pathways distinct from conventional adenomas. The association between sessile serrated polyps and conventional adenomas is not well known. We hypothesize that individuals who have coexistent sessile serrated polyps and conventional adenomas express a more severe phenotype than those harboring lesions from only one pathway. We compare colorectal phenotypes among individuals with sessile serrated polyps, those with conventional adenomas, and those expressing both. This investigation is a retrospective cross-sectional study of 3 cohorts. This study was conducted in multiple centers within 1 health care system. Individuals with sessile serrated polyps and/or conventional adenomas on first lifetime colonoscopy were included in the study. The demographics and polyp characteristics were compared among 3 cohorts to determine the differences in phenotypic expression. Two hundred sixty individuals with sessile serrated polyps and 173 with only conventional adenomas were included. The disease phenotype was most severe in individuals with coexistent sessile serrated polyps and adenomas. The sessile serrated polyps in this cohort were larger (P = .01) than in the serrated-only cohort. The conventional adenomas in this cohort were more numerous (P = .035) and more advanced (P = .046) than in the adenoma-only cohort. Synchronous colorectal cancers were found exclusively in the cohorts with sessile serrated polyps, although this did not reach statistical significance (P = .06). Cross-sectional design precluded the ability to assess for metachronous lesions. Sessile serrated polyps, but not all polyps, were reviewed. Individuals who coexpress sessile serrated polyps and conventional adenomas have an aggressive colorectal phenotype. They harbor larger sessile serrated polyps and more numerous and advanced adenomas than individuals with only sessile serrated polyps or adenomas. Synchronous colorectal cancers were found exclusively in cohorts with sessile serrated polyps. Individuals with sessile serrated polyps, especially with coexistent conventional adenomas, appear to be a high-risk group, which needs to be accounted for when calculating postpolypectomy surveillance intervals.