Efficacy and safety of underwater ESD with water pressure method for colorectal neoplasm: a propensity score matching

Aims Endoscopic submucosal dissection (ESD) for colorectal neoplasm has been widely accepted treatment, but it has been difficult technically not yet, and so various methods and devices have been reported. Therefore, we introduced underwater ESD with water pressure method (U-ESD) from 2020. We evaluated the efficacy and safety of treatment for colorectal neoplasm by U-ESD compared with conventional ESD (C-ESD).

Methods This retrospective observation study investigated 291 patients with 311 colorectal lesions diagnosed endoscopically, and treated between August 2016 and December 2022 enrolled. Of these, excluding one case having 2 lesions resected by C-ESD and WPM-ESD respectively, we identified 290 patients 309 lesions (123 patients 133 lesions in U-ESD group, 167 patients 176 lesions in C-ESD group) and compare the treatment results between the groups. Furthermore, of 311 lesions, excluding four cases of interruption and one case of piecemeal mucosal dissection, we identified 306 colorectal neoplasms in 291 patients (123 patients 132 lesions in U-ESD group, 167 patients 174 lesions in C-ESD group), analyzed the clinical characteristics of the lesions and compared procedure time. Finally, using propensity score matching, procedure time were compared between matched groups.

Results En bloc resection rates of U-ESD group and C-ESD group were 99% and 98% (p=0.63), respectively. There was no differences in intraoperative perforation rate and delayed bleeding rate of U-ESD group and C-ESD group (perforation: 3.0% vs 2.9%(p=0.92), bleeding: 4.1% vs 4.2%(p=0.96)). In analysis per lesions, the proportion of colonic lesion in U-ESD group was greater than in C-ESD (colon/rectum were 118/14 lesions in U-ESD group and 110/64 lesions in C-ESD group, p<0.01). Tumor size of U-ESD group was smaller than of C-ESD (23±9.3 mm vs 27±12 mm, p<0.01). The procedure time was significantly longer in the C-ESD group than WPM-ESD(WPM-ESD: 50±28 min, C-ESD: 65±52 min, p<0.01). Using propensity score matching, we identified 92 lesions in 92 patients from each of the two groups matched for tumor size and location. After matching, the tumor location (colon/rectum) were 80/12 lesions in both groups. Tumor size of U-ESD group was 23±7.5 mm, and of C-ESD group was 24±8.2 mm. The procedure time of WPM-ESD was significantly shorter than that of C-ESD (49±26 min vs 58±42 min, p=0.032)

Conclusions Underwater ESD with water pressure method for colorectal tumor can shorten the procedure time.