Risk of residual neoplasia after a noncurative colorectal endoscopic submucosal dissection for malignant lesions: a multinational study

Background Endoscopic submucosal dissection (ESD) in colorectal lesions is technically demanding and a significant rate of noncurative procedures is expected. We aimed to assess the rate of residual lesions after a noncurative ESD for colorectal cancer (CRC) and to establish predictive scores to be applied in the clinical setting. Methods Retrospective multicenter analysis of consecutive colorectal ESDs. Patients with noncurative ESDs performed for the treatment of CRC lesions submitted to complementary surgery or with at least one follow-up endoscopy were included. Results From 2255 colorectal ESDs, 381 (17%) were noncurative, and 135 of these were performed in CRC lesions. A residual lesion was observed in 24 patients (18%). Surgery was performed in 96 patients and 76 (79 %) had no residual lesion in the colorectal wall or in the lymph nodes. The residual lesion rate for sm1 cancers was 0 %, and for > sm1 cancers was also 0% if no other risk factors were present. Independent risk factors for lymph node metastasis were poor differentiation and lymphatic permeation (NCLymph score). Risk factors for the presence of a residual lesion in the wall were piecemeal resection, poor differentiation, and positive/indeterminate vertical margin (NC-Wall score). Conclusions Lymphatic permeation or poor differentiation warrant surgery owing to their high risk of lymph node metastasis, mainly in > sm1 cancers. In the remaining cases, en bloc and R0 resections resulted in a low risk of residual lesions in the wall. Our scores can be a useful tool for the management of patients who undergo noncurative colorectal ESDs. © 2023 Georg Thieme Verlag. All rights reserved.