Confocal chromoscopic endomicroscopy is superior to chromoscopy alone for the detection and characterisation of intraepithelial neoplasia in chronic ulcerative colitis

The diagnosis of intraepithelial neoplasia is pivotal for ongoing clinical management decisions in ulcerative colitis. Previous studies have compared the diagnostic yield of endomicroscopy with conventional "white light" endoscopy and hence the overall objective increase of endomicroscopy targeted biopsies as compared to chromoscopy guided alone is not apparent.We performed a prospective randomised controlled study to compare the diagnostic yield of intraepithelial neoplasia and cancer in patients undergoing ulcerative colitis screening using chromoscopy assisted endomicroscopy (group A) versus pan-colonic chromoscopy assisted colonoscopy (group B).Patients were randomised in a 1:1 ratio to undergo screening colonoscopy using either chromoscopic endomicroscopy or chromoscopy alone with targeted biopsies. Circumscribed lesions were characterised using endomicroscopy and chromoscopy with pit pattern analysis. Targeted biopsies in addition to conventional 10 cm quadrantic biopsies were taken. Primary outcome addressed the number of intraepithelial neoplasias detected in each group.Endomicroscopy targeted biopsies significantly increased the yield of intraepithelial neoplasia as compared to pan-chromoscopy and biopsy alone (p<0.001) and also increased the yield of high-grade dysplastic lesions (p<0.001). Endomicroscopy targeted biopsies increased the diagnostic yield of intraepithelial neoplasia as compared to chromoscopy guided biopsies alone by 2.5-fold.This is the first randomised controlled study to show the true clinical benefit of endomicroscopy for the in vivo detection and characterisation of intraepithelial neoplasia in chronic ulcerative colitis surveillance colonoscopy. Endomicroscopy with targeted biopsy may potentially be the "gold standard" for the detection of intraepithelial neoplasia in ulcerative colitis.