A Novel Clinical Decision Support Tool to Predict Submucosal Invasive Cancer Within Large Non-Pedunculated Colorectal Polyps

Colorectal cancer can be effectively prevented by removal of pre-malignant polyps during colonoscopy. Large (\>=20mm) non-pedunculated colorectal polyps (LNPCPs) require careful assessment before treatment. If submucosal invasive cancer (SMI) is present, it determines whether endoscopic treatment can be curative or whether surgery is needed. Current classification systems to detect SMI are complex, require extensive training, and are underused in non-tertiary hospitals. A simple web-based clinical decision support tool was created using well-established parameters (presence of a demarcated area, polyp size, Paris classification, location, and granularity) to identify SMI within LNPCPs. Crucially, the tool uses only standard endoscopic imaging available in most endoscopy units. This prospective multi-centre study evaluates the accuracy of the tool during live endoscopic assessment. Endoscopists of varying experience will assess 10 large colorectal polyps using the tool, then undergo a 45-minute structured educational intervention. They will then assess a further 10 polyps using the tool. A third set of 10 assessments at 3 months evaluates durability of learning. Accuracy is compared to expert opinion.

Inclusion Criteria: Endoscopist participants * Gastrointestinal endoscopists of varying abilities and grades * Endoscopists who have not previously encountered the clinical decision support tool Patient participants * Referred for colonoscopy with appropriate bowel preparation * Colorectal polyp \>=20mm in size detected or referred for resection * Non-pedunculated morphology * Non-sessile serrated morphology * Signed informed consent for the procedure and trial participation Exclusion Criteria: Endoscopist participants: * Does not consent to inclusion * Does not undergo the learning intervention * No connection with endoscopy in gastroenterology Patient participants: * Does not consent to data collection for the study * Video of inadequate quality as per opinion of the principal investigator