A recent multicentre randomised controlled trial compared autofluorescence imaging (AFI) with CE for dysplasia detection in colonoscopy surveillance of patients with longstanding UC (FIND-UC). In this study, CE detected significantly more dysplastic lesions per patient compared with AFI. It is unclear whether this increased dysplasia detection also translates to a reduction of dysplasia at follow-up colonoscopy. The aim of this pre-specified study is therefore to prospectively determine whether there is a difference in dysplasia detection at follow-up colonoscopy between UC patients who were randomized to AFI or CE at index colonoscopy for the FIND-UC trial.

Patients are eligible for inclusion in this study when they meet the following criteria:

Inclusion criteria

In order to be eligible to participate in this study, a subject must meet all of the following criteria:

- Patients that where included in the previous FIND-UC trial

Exclusion criteria

A potential subject who meets any of the following criteria will be excluded from participation in this study:

• Patients who not receive their surveillance colonoscopy with CE
• Patients who not undergo their surveillance colonoscopy within 3 months of the surveillance recommendations

Withdrawal of individual subjects

A patient will be excluded from the study if any of the following events occur:

• Withdrawal of informed consent
• The patient requests to be discontinued from the study
• The bowel preparation is scored as Boston Bowel Preparation Scale <6
• Incomplete colonoscopy because the endoscopist is unable to intubate the cecum during the colonoscopy
• The Mayo-score > 1 in at least in one of the bowel segments

Patients of the FIND-UC trial that undergo a follow surveillance colonoscopy