The submucosal fibrosis: what does it mean for colorectal endoscopic submucosal dissection?

Background/Aims: Endoscopic submucosal dissection (ESD) allows removal of colorectal epithelial neoplasms en bloc regardless of size. Colorectal ESD is a difficult procedure because of technical difficulties and risks of complications. This study aimed to assess the relationship between ESD outcome and degree of submucosal fibrosis. Methods: Patients with colorectal tumors undergoing ESD and their medical records were reviewed retrospectively. The degree of submucosal fibrosis was classified into three types. The relationship between ESD outcome and degree of submucosal fibrosis was analyzed. Results: ESD was performed in 158 patients. Thirty-eight cases of F0 (no) fibrosis (24.1%) and 46 cases of F2 (severe) fibrosis (29.1%) were observed. Complete resection was achieved for 138 lesions (87.3%). Multivariate analysis demonstrated that submucosal invasion of tumor and histology of carcinoma were independent risk factors for F2 fibrosis. Severe fibrosis was an independent risk factor for incomplete resection. Conclusions: Severe fibrosis is an important factor related to incomplete resection during colorectal ESD. In cases of severe fibrosis, the rate of complete resection was low even when ESD was performed by an experienced operator. Evaluation of submucosal fibrosis may be helpful to predict the submucosal invasion of tumors and technical difficulties in ESD.