Histology of colonic submucosal lesions reveals a high proportion of benign lesions that do not require R0 en bloc endoscopic resection.

Background and study aims: Submucosal lesions in the colon are much rarer than those in the rectum. Their nature is poorly understood, as is the best technique for their excision. Based on that of rectal lesions, it most often aims for R0 en bloc resection, but without formal proof of efficacy. The aim of this study was to evaluate histology of these lesions and determine whether submucosal lesions of the colon always require R0 en bloc endoscopic resection. Patients and methods: We conducted a retrospective international study of all colonic submucosal lesions with confirmed histology by resection or biopsy. We assessed the proportion of lesions correctly managed by endoscopy, so that the proposed resection technique offered a level of tumor resection quality appropriate to the definitive histology of the lesion. Results: One hundred patients with 105 colonic submucosal lesions from 13 European centers were included. Histology revealed 91.4% (96/105) non-malignant lesions and 8.6% (9/105) malignant lesions. Endoscopic techniques used were curative in 41.7% (5/12) of cases requiring resection, non-curative in 58.3% (7/12), and endoscopic resection was not necessary in 88.7% (93/105). There was no delayed surgery for adverse events. Conclusions: Most colonic submucosal lesions are non-malignant and do not warrant advanced endoscopic resection. A new therapeutic approach could be first-line use of a low-risk, low-cost histological diagnostic technique followed in a second phase by a more advanced technique in the event of a malignant histological result. Further studies are needed to evaluate this step-up strategy.