Unsedated Colonoscopy for Colorectal Cancer Screening and Surveillance

In a prospective, randomized, controlled study, two methods (water method vs. air method) of performing colonoscopy will be compared in patients undergoing unsedated colonoscopy for CRC screening. The investigators hypothesize that: 1. Study method increases overall cecal intubation with comparable assessment of current experience and patient willingness to repeat future colonoscopy compared with conventional colonoscopy 2. Study method improves bowel preparation and increases polyp pickup rate