Assessing Effect of Withdrawal Time on Adenoma Detection Rate for Screening Colonoscopy

The investigators' null hypothesis is that a withdrawal time of 9 to 10 minutes is non-inferior to a withdrawal time of 12 minutes or greater. Thus, the goal of this tandem design trial is to compare the additional diagnostic yield (# of missed lesions) for withdrawal times exceeding 10 minutes for screening/surveillance colonoscopies. Although withdrawal times longer than the standard 6-minute recommendation have been shown to be beneficial, there is limited prospective evidence investigating the benefit or lack thereof for withdrawal times greater than 9-10 minutes.