Do flat polyps have an increased risk for high-grade dysplasia? – Evaluation of the macroscopic findings in a large Austrian screening colonoscopy study

Background and Aim: Flat adenomas are suspected to have a high capacity for progression and a considerable more aggressive tendency for malign degeneration than other adenomas. We suggest that also the macroscopic shape matters: the flatter a polyp is, the harder it will be detected. Nevertheless, in most of the screening studies, the macroscopic polyp morphology is not surveyed. The aim of this study was to evaluate the percentage of flat polyp findings in a screening population. Methods: We performed a cross-sectional analysis of the data from a large Austrian colonoscopy-based screening program that included…