Risk stratification of colorectal polyps for predicting residual or recurring adenoma using the Size/Morphology/Site/Access score

Background and Aims Endoscopic mucosal resection is an effective and safe procedure to manage large non‐pedunculated colonic polyps for which residual/recurrent adenoma is the main drawback. Size/Morphology/Site/Access score determines polypectomy difficulty. We aimed to describe residual/recurrent adenoma rate according to Size/Morphology/Site/Access and to select the ize/Morphology/Site/Access cut‐off to predict low residual/recurrent adenoma. Methods This was a retrospective cohort study of endoscopic mucosal resection for large non‐pedunculated colonic polyps performed in a tertiary centre. Results Three hundred and sixteen procedures were included. The mean size of lesions was 34.5 ± 17.1 mm, 59.5% were sessile, 60.4% were in the right colon and in 17.7% ( n  = 56) the access was difficult. Of the lesions, 83.6% were Size/Morphology/Site/Access 3–4. Residual/recurrent adenoma at first and second follow‐up was significantly lower in Size/Morphology/Site/Access 2 (1.9% and 0.0%, respectively) when compared to Size/Morphology/Site/Access 3 (18.2%, p  = 0.004 and 6.7%, p  = 0.049) and Size/Morphology/Site/Access 4 (30.8%, p  < 0.001 and 22.7%, p  = 0.030). The negative predictive value of Size/Morphology/Site/Access 2 for residual/recurrent adenoma at second follow‐up was 86.1%. On multivariate analyses, Size/Morphology/Site/Access 3–4 predicted residual/recurrent adenoma at first (odds ratio 11.96, 95% confidence interval 1.57–91.13) and second follow‐up (odds ratio 2.47, 95% confidence interval 1.51–4.22) and had higher cumulative incidence of residual/recurrent adenoma compared to Size/Morphology/Site/Access 2 ( p  ≤ 0.003). Conclusion Use of the Size/Morphology/Site/Access score allows cases to be identified with a low risk of residual/recurrent adenoma.