Endoscopic Tri-Modal Imaging (ETMI) for the detection and classification of early colorectal neoplasia: a multicentre randomised controlled trial

Background and study aims
A colonoscopy is an examination where a long flexible tube (endoscope) with a light and camera on the end is inserted through your back passage. This enables the doctor or nurse to get a clear view of the bowel lining to look for polyps. These polyps are potentially dangerous because a small number of them become malignant after several years. This is why it is important that the endoscopist finds these polyps and removes them. We know from previous research that a number of polyps are being missed during a colonoscopy. There are different reasons for a polyp to be missed; they can be very small or hidden behind a fold, for example. Normally, a colonoscopy is performed with standard white light. Several new techniques have been developed to improve the quality of colonscopy. These new techniques have made it possible to better visualize the colon, which could lead to fewer polyps being missed. One of these techniques is called autofluorescence imaging (AFI), another new technique is called narrow band imaging (NBI). During AFI, the colon is being inspected with fluorescing light, while during NBI the colon is being inspected with a particular wavelength of light (mostly blue). Both of these techniques can be incorporated into a normal endoscope. This means that an endoscopist can change between any of the techniques by pressing a button on the endoscope. The aim of this study is to compare the two new techniques (AFI and NBI) with the standard technique, which is normal white light.
Who can participate?
Patients aged over 18 undergoing colonoscopy because of polyps or colorectal cancer in the past, complaints such as changes in bowel habits or rectal blood loss, or family history of colorectal cancer.
What does the study involve?
The preparation before the colonoscopy (bowel cleansing) is done as usual. The colonoscopy itself is also similar to a regular colonoscopy. In order to assess whether any of these techniques are better at detecting polyps, we need to know whether any polyps are being missed. This means that the colon needs to be inspected twice. Participants are randomly allocated into two groups; for one group the colon is inspected twice with standard white light, while the other group will have inspection with white light first and AFI/NBI during the second inspection.