I-Scan Versus High-definition White Light

• Mean number of adenomas per colonoscopy [ Time Frame: Colonoscopy report form provided to the physician will be filled out and collected after the procedure (1 hour). All polyps reviewed by pathologist (1 week). ] [ Designated as safety issue: No ]
  The "Colonoscopy Report Form" completed by the Physician helps to assess the number of polyps and a endoscopic description (location, size, shape) of these lesions including. Following formal review by the pathologist the polyp classification (e.g. whether it is an adenoma) is determined.
  
  

• Number of adenomas detected in the right colon during the second look [ Time Frame: Second look in the right colon and finally withdrawing through the entire colon (approximately 5 min) ] [ Designated as safety issue: No ]
  The planned "Second Look" of the right colon will involve withdrawing from the cecum to hepatic flexure, then re-inserting to the cecum and finally withdrawing through the entire colon. This is to determine if a "Second Look" in the right colon increases the mean number of adenomas detected compared with a single inspection irrespective of the imaging modality.
  
  
• To estimate the recruitment rate [ Time Frame: Upto 8 months ] [ Designated as safety issue: No ]

  Recruitment rates will be reported as follows:

  1. No. of patients given the study invitation letter
  2. No. of patients who return the form as interested
  3. No. of patients who provided informed consent
  4. No. of patients who complete the study protocol
  
  

Colorectal Cancer is the third most common cause of cancer in Canada with an estimated lifetime risk of developing the disease of 6-7%. Each year there are approximately 21,000 new cases and 9,100 deaths attributable to this disease. Colonoscopy is one of several methods recommended for CRC screening by current guidelines. While colonoscopy is the most invasive, it offers high diagnostic accuracy and ability for therapy (biopsy and removal of adenomas) compared to other modalities. The emerging evidence regarding missed neoplastic lesions with colonoscopy has resulted in quality initiatives designed to improve colonoscopy performance. I-Scan (Pentax, Montvale, NJ) is a new method that uses post processing computer algorithms to revise the standard white light to highlight pit patterns and vascular surface patterns.The relevant I-scan settings in the colon are I-scan 1 and I-scan 2. The primary objective of the study is to compare the adenoma detection rate in the right colon using High-definition white light colonoscopy versus I-scan enhanced colonoscopy.

All patients referred for a screening colonoscopy at Forzani and MacPhail Colon Cancer Centre will be considered for enrollment.All eligible patients that are not part of another research study will be approached for enrollment into the study. During the pre-assessment at the clinic a study assistant will contact all the eligible patients to describe the study and provide an "Invitation to participate in a Research study" form. The study assistant will obtain a final consent if they agree. Those not interested will simply receive the Centre's standard protocol. There will be no coercion of any sort. Following Informed Consent, treatment allocation through computer generated randomization will be revealed. Patients will be allocated to one of the three study arms (HD Colon, I-scan 1 and I-Scan 2). Patients will receive a standard bowel preparation: Split dose Polyethylene Glycol (PEG) (2L at noon + 2L at 8 PM the day before) for morning procedures or (2L at 8Pm the day before and 2L at five hours before the procedure on the day of colonoscopy) for afternoon procedure. certified gastroenterologists will perform all of the procedures with the assistance of a nurse. The planned "second look" of the right colon will involve withdrawing from the Cecum to Hepatic flexure, then re-inserting to Cecum and finally withdrawing through the entire colon. The physician performing the procedure will then fill a "Colonoscopy Report Form" including the number of polyps detected, size, shape, polypectomy method and cleanliness of the bowel.