Clinical implications of low grade dysplasia found during inflammatory bowel disease surveillance: a retrospective study comparing chromoendoscopy and white-light endoscopy.

 Current guidelines recommend the use of pancolonic chromoendoscopy for surveillance of patients with inflammatory bowel disease (IBD). It is currently unknown whether low grade dysplasia (LGD) found using chromoendoscopy carries a similar risk of high grade dysplasia (HGD) or colorectal cancer (CRC) compared with LGD detected using white-light endoscopy (WLE). The aim of this study was to compare the risk of advanced neoplasia, a combined endpoint of HGD and CRC, during follow-up after detection of lesions containing LGD identified with either chromoendoscopy or WLE.  A retrospective cohort was established to identify patients who underwent IBD surveillance for ulcerative colitis or colonic Crohn's disease between 2000 and 2014. Subgroups were identified, based on the endoscopic technique (standard definition resolution WLE, high definition resolution WLE or chromoendoscopy). LGD detected in random biopsies was considered invisible LGD. Patients were followed until detection of advanced neoplasia, colectomy, death, or the last known surveillance colonoscopy.  Of 1065 patients undergoing IBD surveillance, 159 patients underwent follow-up for LGD, which was visible in 133 cases and invisible in 26 cases. On follow-up, five cases of HGD and five cases of CRC were detected. The overall incidence rate of advanced neoplasia was 1.34 per 100 patient-years with a median follow-up of 4.7 years and a median time to advanced neoplasia of 3.3 years. There were no significant differences in the incidence of advanced neoplasia between chromoendoscopy-detected and WLE-detected LGD.  Advanced neoplasia was found to develop infrequently after detection of LGD in patients undergoing endoscopic surveillance for IBD. LGD lesions detected with either chromoendoscopy or WLE carry similar risks of advanced neoplasia over time.