Hybrid endoscopic submucosal dissection as a salvage option for difficult colorectal conventional endoscopic submucosal dissection

Background: When total submucosal dissection is difficult to achieve during conventional colorectal endoscopic submucosal dissection (C-ESD), the lesion can be resected by final snaring through salvage hybrid ESD (SH-ESD). This study aimed to examine the outcomes of SH-ESD and identify its indications that could achieve en bloc resection.Methods: We recruited 1039 consecutive patients with colorectal lesions that underwent ESD at Hiroshima University Hospital between January 2015 and December 2020. C-ESD was attempted thoroughly in 924 lesions (C-ESD group, including 9 lesions in which ESD was discontinued), and SH-ESD was performed owing to some difficulties in 115 lesions (SH-ESD group). Risk factors for incomplete resection by SH-ESD and ESD discontinuation were evaluated using multivariate analysis. The outcomes were compared between cases with remaining undissected submucosa of < 20 mm in diameter in the SH-ESD and C-ESD groups, using propensity score matching.Results: Multivariate analysis revealed that a procedure time > 80 min and remaining undissected submucosa >= 20 mm in diameter were significant risk factors for incomplete resection after SH-ESD and ESD discontinuation. By propensity score matching analysis, procedure time was significantly shorter in the SH-ESD group with remaining undissected submucosa < 20 mm in diameter than in the C-ESD group (71 min vs. 90 min, p = 0.0053), although no significant difference was found in the en bloc resection rate (94% vs. 87%, p = 0.0914).Conclusion: SH-ESD can be an alternative surgical method when conventional ESD is difficult to continue in cases in which the remaining undissected submucosa is < 20 mm in diameter.