enrollment terminated, analysis ongoing

Polyps found during screening colonoscopy have to be removed or at least biopsied. Attempts to save costs include endoscopic assessment of polyps with regards to differential diagnoses between adenomas (which have to be removed) and hyperplastic polyps (could be left in place or removed and not examined histologically). Such a concept would only be feasible if endoscopy can make the differential diagnosis with high accuracy. Such high accuracy rates - between 80% and 95% - have been reported from reference centers with specific scientific interest. The investigators want to test whether these results a) can be reproduced in the private practice setting performing large-volume screening colonoscopies and b) whether latest generation endoscopes provide benefit in terms of better accuracy.

Patients undergoing screening colonoscopy will be randomized to the use of two different colonoscopes, namely the latest generation (Pentax iScan, Hi Line) versus the previous generation (Classic Line). On withdrawal, all polyps found will be diagnosed according to their pit pattern (classification scheme mit example images provided) and a differential diagnosis made during the live examination. Pit patterns I/II will be classified as hyperplastic polyps, patterns III-V as adenomas (in a subgroup IV and V will be classified as pre-/malignant). All polyps will be photographed from near distance to allow for later blinded review which will be done on patients with only one polyp (to avoid mix-up of polyps) by 3 examiners and 2 independent hospital experts.

Inclusion Criteria:

• All patients undergoing screening colonoscopy

Exclusion Criteria:

• Missing consent
• No screening colonoscopy (diagnostic colonoscopy because of symptoms)