Prevalence of Advanced Histology in Small and Diminutive Colon Polyps

Abstract

Introduction: Colorectal cancer remains a common malignancy in the United States, with an estimated 135,000 cases newly diagnosed in 2016, according to the National Cancer Institute. The concept of the adenoma-adenocarcinoma sequence is widely accepted as a predominant pathway underlying the development of colorectal cancer. Substantial data have correlated polypoid lesion growth with carcinogenesis; however, the clinical significance and endoscopic strategies for management of small and diminutive polyps has been widely debated. In the current era marked by promotion of cost-effective care, the existing guidelines for surveillance have been questioned. The goal of this study was to characterize the prevalence of advanced histology and adenocarcinoma in small and diminutive polyps. Methods: A retrospective study was performed which reviewed consecutive screening and surveillance colonoscopies completed at an academic medical center between 2015 and 2017 and the corresponding pathology reports. Polyps were divided into 3 groups by size: (0-5mm), (6-10mm) and (>10mm). Polyps were then characterized by histology including hyperplastic, adenoma, serrated adenomas, villous component, high-grade dysplasia and cancer. Advanced histology was defined as those polyps with villous component or high-grade dysplasia. Results: A total of 3820 polyps were analyzed with 2743 polyps detected in the 0-5mm category, 803, in the 6-10mm category and 274, in the >10mm category. Of the polyps in the 0-5mm category, 1904 (69.4%) were adenomas while advanced histology was found in 18 polyps (0.66%) and adenocarcinoma in 1 polyp (0.04%). In the 6-10mm category, 534 (66.5%) were adenomas, 37 (4.61%) showed advanced histology and 5 (0.62%) were adenocarcinoma. Lastly, in the >10mm category, 139 (50.7%) were adenomas, 82 (18.6%) were advanced histology and 9 (3.3%) adenocarcinomas were detected. Conclusion: Similar to prior studies, the rates of advanced adenomas in diminutive and small polyps remain low; however, a significant increase in prevalence occurs between 0-5mm and 6-10mm in size. Additionally, adenocarcinoma was detected in 1 polyp, 0-5mm in size and in 5 polyps, 6-10mm in size. This data, questions the “predict, resect, and discard” strategies given the lack of endoscopic tools available to correctly predict histology at this time. We conclude that small and diminutive polyps still warrant resection and histologic examination in congruence with current guidelines.