P106 Cromoendoscopy versus second generation Narrow band Imaging for dysplasia detection in IBD. An interim analysis of a prospective randomized control trial.

Martin Arranz, E.(1);Suarez Ferrer, C.(1);García Ramirez, L.(2);Sanchez Azofra, M.(1);Rueda García, J.L.(1);Poza Cordón, J.(1);Martín Arranz, M.D.(1);

(1)Hospital Universitario La Paz. Hospital La Paz Institute for Health Research IdiPAZ, Gastroenterology department, Madrid, Spain;(2)Hospital La Paz Institute for Health Research IdiPAZ, Gastrointestinal immunomediated diseases group, Madrid, Spain


Colonic neoplastic risk is increased in long-standing colitis. Chromoendoscopy (CE) is the recommended screening method. Narrow band imaging (NBI) is potentially a more convenient alternative. Few studies have explored the diagnostic yield of second generation NBI (Olympus 190 series) versus chromoendoscopy. 


NBICromo (NCT04403997) is an ongoing prospective randomized controlled trial in which patients with clinical indication for CE (>8 years of disease, left-side or extensive colitis, colonic Crohn´s disease with >2 colonic segments affected or associated primary esclerosing cholangitis) are randomized on 1:1 ratio to CE with methylene blue 0,1% or NBI. All procedures are done with Olympus HQ190 endoscopes by endoscopists with experience in IBD. Biopsies are taken from all visible lesions. Primary objective is to compare the total number of neoplastic lesions detected in each group. Secondary objectives are to compare the procedure time, the number of biopsies taken,and the accuracy of optical characterization of the lesions. The study has been approved by the Hospital Ethics Committee and patient informed consents were obtained.
Estimated sample size for the study is 175 patients, and recruitment is currently ongoing. An interim analysis was conducted with the first 75 randomized patients to exclude futility due to slowed recruitment caused by covid-19 pandemic .


75 patients were randomized, 34 to CE and 41 to NBI. 10 patients were excluded due to presence of inflammation or poor bowel preparation in the colonoscopy. 65 patients were analyzed per protocol, 31 in the CE arm and 34 in the NBI arm. Mean age was 57±13 years, 46.15% were male and 53.85% female. Mean disease duration was 17.1 ± 8.3 years. No significant differences were found between groups in basal characteristics.
123 lesions were detected. 77 with CE and 46 with NBI, of these 34 (27,6%) were neoplastic (14 neoplastic lesions were found in NBI group and 19 in CE group p=0.1. Neoplastic lesions were found in 13 patients in CE group (41,9%) and 7 patients with NBI (20,5%) p=0.06. Total withdrawal time (including staining and/or therapeutics) was significantly shorter in the NBI group (17.6 ±9.8 vs 30.5 ± 16.5 min p<0.001). No differences were found in biopsies numbers (2.5 ± 2.5 CE vs 1.7 ±1.6 NBI p=0.16).
AE were 1 mild post resection bleeding and 1 mild fever, both in the CE group p=0.07.


In this interim analysis there are no significant differences in dysplasia detection between CE and NBI, although more sample size is needed. NBI could be a more convenient alternative to CE, with significant shorter and more simple procedures. The ongoing clinical trial will be completed.