Risk Stratification for Covert Invasive Cancer Among Patients Referred for Colonic Endoscopic Mucosal Resection: A Large Multicenter Cohort

In a prospective study of 2106 patients who underwent EMR for large sessile or flat colorectal polyps or laterally spreading lesions, we associated rectosigmoid location, combined Paris classification and surface morphology, and increasing size with increased risk for covert malignancy. Rectosigmoid 0-Is and 0-IIa+Is non-granular lesions have a high risk for malignancy, whereas proximally located 0-Is or 0-IIa granular lesions have a low risk. These findings can be used to inform decisions on which patients should undergo endoscopic submucosal dissection, EMR, or surgery. ClinicalTrials.gov, Number: NCT02000141.