ScopeGuide-assisted Colonoscopy Versus Conventional Colonoscopy for Improved Endoscopic Performance and Enhanced Patient Experience

Summary of Research Proposal

Background:

Colon and rectal cancer (CRC) is a leading cause of cancer-related morbidity and mortality in Canada. Colonoscopy is the preferred screening modality for CRC and has been shown to decrease the likelihood of developing CRC as well as CRC-related mortality, particularly through the detection and removal of potentially pre-cancerous polyps, with the aim of preventing colon cancer, and for the diagnosis of early stage CRC that is more likely to be treatable and result in long-term survival. However, recent evidence suggests that colonoscopy has not been as universally protective against CRC as had been previously hoped, particularly for proximal cancers located in the right colon. Theories as to why this might be the case include speculation about altered biology of cancers that develop in the proximal colon and technical issues relating to the performance of colonoscopy itself. In particular, one of the problems is incomplete colonoscopy that fails to examine the entire colon to the cecum, which may occur in 10-20% of cases. Furthermore, from a public health standpoint, a considerable proportion of the population remain averse to undergoing colonoscopy, particularly because of fears of procedure discomfort, decreasing the potential impact for overall CRC reduction. Thus, optimizing the technical performance of colonoscopy and improving its acceptance among patients is important for maximizing the possible benefits to society.

One of the most common reasons for incomplete colonoscopy is excessive internal looping of the endoscope. This looping has also been shown to be the major cause of patient discomfort during the procedure. Experts agree that colonoscopy is most successful at reaching the cecum and most comfortable for patients when the endoscope is kept in a straight position by minimizing loop formation and reducing loops once they have formed. Thus, identification and reduction of endoscope loops is critically important for the successful and comfortable completion of colonoscopy. Over the years, several techniques have emerged to overcome loop formation, including withdrawal of the endoscope with torque, abdominal wall pressure and patient position changes, yet these are all done in a "trial and error" fashion. Despite this limitation, these maneuvers form the cornerstones of current colonoscopy technique. Technological innovations such as smaller caliber "pediatric" colonoscopes and "variable stiffness" colonoscopes with adjustable rigidity have been introduced that have had moderate success in diminishing patient discomfort and increasing rates of colonoscopy completion. Yet despite these efforts to improve colonoscopy practice, the reality is that many procedures are still done poorly. An audit of all colonoscopies performed in Winnipeg from 2004 to 2006 demonstrated a dismal completion rate of only 65%. Thus, something more clearly needs to be done. In an effort to help improve colonoscopy from both the technical standpoint of the endoscopist and also the comfort level of patients, Olympus has redesigned a previously developed real-time imaging system that enables visualization of the shape of the entire endoscope while it is inside the patient's body. This technology, called ScopeGuide (Olympus America, Center Valley, PA), consists of electromagnetic coils embedded within the endoscope that are detected by an external receiver dish, generating a 3D representation of the endoscope that is displayed on a monitor. It is anticipated that by visualizing the entire scope as it moves through the body, endoscopists will gain useful visual information about loop formation and scope position that will enable greater technical success while creating a more comfortable patient experience.

Study Objectives: