Risk Stratification System for Evaluation of Complex Polyps Can Predict Outcomes of Endoscopic Mucosal Resection

BACKGROUND: Apart from size, little is known about what makes a colonic polyp difficult to endoscopically remove. OBJECTIVE: The aim of this study was to evaluate polyp complexity by using a novel classification system and to assess how this affects success at endoscopic resection. DESIGN: This prospective cohort study was conducted at a tertiary referral center in the United Kingdom. INTERVENTIONS: Data were collected on patients referred for endoscopic resection of polyps >2 cm in size. Lesions were classified on the basis of size, morphology, site, and ease of access with the use of a novel scoring system (size/morphology/site/access). Endoscopic resection was performed to resect the lesions. Patients were followed up endoscopically to assess clinical outcomes. MAIN OUTCOME MEASURES: The primary outcomes measured were the endoscopic cure and complication rate by size/morphology/site/access grade and the cost savings of endoscopic resection over surgery. RESULTS: Endoscopic resection was performed on 220 patients (135 male) with 220 polyps, mean size of 43 mm (range, 20 mm-150 mm). Thirty-seven percent were classified as size/morphology/site/access 2 or 3; 63% were classified as the most challenging size/morphology/site/access level 4. Complete endoscopic clearance was achieved in 90% of cases with the first endoscopic resection attempt, improving to 96% with further endoscopic resection attempts. There were complications in 18 of 220 (8.1%) of cases. Complications were independent of lesion size and location but were affected by size/morphology/site/access grade (p = 0.018). Probability of clearance at first endoscopic resection attempt was affected by lesion complexity. Size/morphology/site/access 2 and 3 = 97.5 vs SMSA 4 = 87.5% (p = 0.009). Probability of cancer was not affected by size/morphology/site/access grade. For the whole cohort, endoscopic resection represented a cost saving of 726,288 pound ($1,123,858.05) over that of surgery. LIMITATIONS: The main limitation of this study is that it is a single-center, single-endoscopist series. CONCLUSIONS: The size/morphology/site/access scoring system is easy to use and provides valuable information on the lesion complexity and success and complication rates of endoscopic resection. This can be used for service planning, training endoscopists, and providing prognostic information for patients.