Interobserver Agreement in Assessing Dysplasia in Colorectal Adenomatous Polyps: A Multicentric Iranian Study

Background & Objective: Most colorectal cancers (CRCs) arise from adenomatous polyps, and clinical management of this type of polyp is highly dependent on the reliability and validity of the pathological diagnosis. The aim of this study was to examine the interobserver agreement of five pathologists in assessing dysplasia in adenomatous polyps. Methods: In this study, a total of 146 adenomatous polyps of patients undergoing colonoscopy were selected from hospitals of Shahid Beheshti University of Medical Sciences, Tehran, Iran between 2017 and 2018. Five pathologists independently classified adenomatous polyps according to histologic type, nuclear pseudostratification, mitotic activity, nuclear polarity, nuclear pleomorphism, nuclear shape, nucleolus, chromatin pattern, cytology grade, architectural features, dysplasia, and final diagnosis. The overall kappa statistic (k) was used to assess agreement among pathologists. Results: The mean age of the patients was 62.06 ± 13.06 (mean ± SD) with a male-to-female ratio of 2.2:1. The most common site of resection was the sigmoid colon (28.1%). The highest agreement was found for dysplasia grade (k=0.415) and histologic type (k=0.401), whereas the lowest agreement was found for mitotic activity (k=0.185), nuclear shape (k=0.187), and nucleolus (k=0.196). Conclusion: Our findings indicate that agreement among pathologists in assessing dysplasia in adenomatous polyps is within fair to moderate levels of agreement. Therefore, there is a vital need to better clarify the current diagnostic criteria.