Back-to-back Endoscopy Versus Single-pass Endoscopy and Chromoendoscopy in IBD Surveillance

The investigators assume based on previous research a yield of 12% using high-definition white light endoscopy and 24% using either chromoendoscopy or high-definition white light endoscopy with a second examination (Imperatore et al 2019). To show non-inferiority of back-to-back HDWLE compared to CE, with a non-inferiority margin of 10% (power 80% and alpha 5%,) a total of 226 patients per group is required.

To demonstrate a superiority of back-to-back HDWLE compared to a regular HDWLE, with a 1:2 allocation ratio of single-pass vs back-to-back , 113 and 226 patients per group are needed to achieve 80% power with an alpha of 5%. Therefore, the investigators will include 226 patients in group back-to-back HDWLE, 226 in group CE, and 113 patients in group regular HDWLE. This amounts to a total of 560 patients. To account for any screen-failures The investigators will include at most 5% (of 560) additional patients until 80% power is reached.

Inclusion criteria

• Signed informed consent
• Patients with inflammatory bowel disease, an estimated involvement of at least 30% of the colonic surface and a disease duration of at least 8 years (or any disease duration in case of concomitant primary sclerosing cholangitis).
• Previous assessable surveillance endoscopy > 1 year
• Age > 18 years

Exclusion criteria

• Active colitis > 20 cm and/or inflammation resulting in an insufficient surveillance procedure according to the endoscopist.
• Allergy or intolerance to methylene blue
• Insufficient bowel cleansing (BBPS <6)
• Refusing or incapable to agree with informed consent
• Pregnant women
• > 50 % of the colon surgically removed