Background: The characteristics of pathologically measured (PMS) and endoscopically measured sizes (EMS) of the colorectal polyps (CRPs) is poorly understood, particularly in polypoid unremarkable mucosa (PUM), sessile serrated adenoma (SSA), and high-grade dysplasia (HGD).
Methods: To characterize the discordance and correlation between the PMS and EMS of CRPs including PUM, SSA, HGD, hyperplastic polyp (HP) and adenomas, we conducted this prospective observational study on the polyps collected between August 2012 and December 2013.
Results: PMS was significantly smaller than EMS in the 497 qualified CRPs regardless of the sites (left, transverse and right colorectum) or EMS (≥1 cm and <1 cm) subgroups. The PMS and EMS discordance was associated with a diagnosis of HP and adenoma (versus PUM, SSA or HGD), single fragment (versus multiple), 3 of the 8 endoscopists and PMS<1 cm (versus ≥1 cm). Despite a good correlation between EMS and PMS in the adenomas (ĸ=0.626, 95% confidence intervals [CI], 0.505-0.746) and a moderate correlation in the serrated polyps (SPs) including HP and SSA, (ĸ=0.424, 95% CI, 0.244-0.604), 40.4% (23/57) of the adenomas and 63.6% (21/33) of the SPs with EMS≥1 cm might warrant longer follow-up intervals since their PMS were <1 cm. The PMS and EMS had linear correlations except in CRPs with HGD or EMS≥1 cm.
Conclusions: The discordance between PMS and EMS is associated with the pathologic diagnosis, fragment number, endoscopists and PMS, and may lead to different follow-ups in a considerable portion of adenomas and SPs.
Keywords: Polyp; cancer; colonoscopy; measurement; pathology; surveillance.