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DOP080 Final results of a randomised study comparing high-definition colonoscopy alone with high- definition dye spraying and electronic virtual chromoendoscopy using iSCAN for detection of colonic neoplastic lesions during IBD surveillance colonoscopy

M. Iacucci*1, M. Fort Gasia1, A. Oluseyi1, R. Panaccione1, S. Gui X2, S. Urbanski3, P. Minoo3, S. Ghosh1

1University of Calgary, Gastroenterology, Calgary, Canada, 2University of Calgary, Pathology, Calgary, Canada, 3University of Calgary, Calgary, Canada


Dye chromoendoscopy (DCE) is considered the standard of practice for IBD surveillance colonoscopy. However, the most appropriate procedure for optimum detection of neoplastic lesions (NL) is still unclear. The resolution of high-definition (HD) and virtual chromoendoscopy (VCE) colonoscopy has improved substantially, and further studies are needed to determine the optimal endoscopic technique. We aimed to conduct a randomised study comparing 3 different techniques for surveillance colonoscopy to detect colonic NL in IBD: HD, DCE, and VCE.


A randomised study (NCT02098798) was conducted to determine the detection rates of NL with HD alone, HD with DCE or HD with VCE in patients with long standing colitis (8 years from diagnosis, both UC and CD, or PSC with IBD from diagnosis). Consecutive patients with inactive disease were enrolled in 1:1:1 ratio into 3 arms of the study. Colonoscopy was performed using a Pentax EPKi processor and HD video colonoscope (EC-3490Fi; Pentax, Tokyo). Endoscopic colonic lesions were classified by the Paris classification as polypoid/non-polypoid and Kudo pit pattern The NL were histologically categorised by the modified Vienna classification as dysplasia (ALM and DALM), sessile serrated adenomas (SSAs), and adenoma-like polyps (ALP). Chi squared test was used for comparison between the 3 arms. Sensitivity, specificity, PPV, NPV, and accuracy were calculated for each technique. The study was powered to detect an absolute difference in detection of neoplastic lesion of 15% between the HD and VCE groups, with the DSC group being a reference arm.


In the study, 225 consecutive patients (122 = M, median age 49 y, range 20–77 y) were assessed by HD (n = 75), VCE (n = 75) or DCE (n = 75). Further, 31 SSAs were found in 17 patients (7.5%); 45 ALPs were found in 39 patients (17.3%); 7 dysplastic lesions were found in 6 patients (2.7%); adenocarcinoma was found in 1 patient (0.4%). The colonic neoplastic lesions found in each surveillance arm are detailed in Table 1. Neoplasia detection rates were similar amongst the 3 arms of the study (HD: 28%, DCE 22.6%, VCE 17.3%, p = NS). The 3 techniques had similar sensitivity and specificity in detecting DL. HD had a sensitivity of 93.6%, specificity of 85%, PPV 93.6%, NPV 85%, and accuracy 93.85%. DCE had a sensitivity of 86.6%, specificity of 89.6%, PPV 88%, NPV 86.7%, accuracy 87.3%, and VCE had a sensitivity of 92%, specificity of 73.3%, PPV 85.2%, NPV 84.6%, and accuracy 86%.


In this randomised study, we could not demonstrate that DCE has higher detection rates for colonic NL compared with either HD or VCE. In fact, the majority of NL was detected in the HD group, but this was not statistically significant. Overall, 7.5% of the patients had detectable SSA.