Narrow Band Versus Conventional Endoscopic Imaging for Screening Colonoscopy in a Private Practice Setting - A Large Prospective Randomized Trial

in 5 private practices with 6 examiners, consecutive asymptomatic persons willing to undergo screening colonoscopy will be asked to participate in this randomized study.

After introduction of the colonoscope into the cecum, patients will be randomized into withdrawal with either the NBI mode or conventional imaging by using wide-angle colonoscopes with HDTV imaging (Olympus Corp., Hamburg, Germany) in both groups. Randomization lists will be used for group allocation in each individual practice. In the NBI group, switching back to conventional imaging, and the number of occasions for switching back and the reasons for it are documented in this group.

Patients bowel preparation consists mostly of polyethylene glycol lavage with 4-5 liters until clear rectal fluid is evacuated. All examiners shall take special care to wash and clean the entire large bowel during instrument introduction and withdrawal, in order to provide optimal imaging conditions.

The following parameters are documented:

• Age and sex of the patient
• Type and dosage of sedation
• Examination time, both for instrument introduction and withdrawal
• Polyp characteristics: size (measured by open forceps or snare), shape (pedunculated/elevated, sessile/flat, and location
• Polyp histology after removal using snare polypectomy or forceps removal (for polyps < 3 mm), or biopsy if there are contraindications
• Other lesions found such as cancers, diverticula, inflammatory lesions etc. The main outcome parameter is the adenoma detection rate (number of polyps/number of patients examined) in the two groups.