Colonoscopy is the gold standard screening test for colorectal cancer. Removal of pre-malignant colon polyps during colonoscopy reduces colorectal cancer mortality by over 50%. However, while colonoscopy is highly effective at preventing distal (left sided) colon cancers, it provides only limited protection from cancer in the proximal (right side) colon. Our goal is to determine if additional pre-cancerous colon polyps can be identified by looking at the right side of the colon in retroflexion. During retroflexion the tip of the colonoscope is turned 180 degrees; allowing the doctor to view the backs of colonic folds. If additional polyps can be identified in this manner colonoscopy will become a more efficient method of screening for colon cancer.