Clinical effectiveness of the pocket-creation method for colorectal endoscopic submucosal dissection

Background and study aims  Endoscopic submucosal dissection (ESD) is a technically advanced procedure for colorectal tumors. Hayashi et al. invented the "pocket-creation method (PCM)," and reported that Is-type lesions with fibrosis could be efficaciously and safely resected. However, only case studies have been published, and there are no previous reports on the usefulness of PCM in colorectal ESD for all lesions, as compared with the conventional method. This study aimed to evaluate the effectiveness and safety of PCM in colorectal ESD. Patients and methods  Ninety-six colorectal tumors were treated: 47 using the PCM and the other 49, considered the control group, using the conventional method. Therapeutic effectiveness and safety were retrospectively assessed. Results The comparison between the PCM and control groups revealed higher rates of en bloc resection (100 % vs. 88 %, P  = 0.015) and curative endoscopic resection (100 % vs. 84 %, P  = 0.0030) with PCM. There was no significant difference in perforation as an adverse event (AE) between the two groups, though perforation was observed in only 6 % of the control group and none of the PCM group. Compared with the control group, the PCM group had lower incidences of perforation and post-ESD coagulation syndrome, and both AEs were associated with excessive thermal denaturation of the muscle layer (2 % vs. 16 %, P  = 0.018). Conclusions This study demonstrated the effectiveness and safety of ESD with PCM for colorectal tumors. Although there is a possible learning curve, PCM enables the endoscopist to safely perform ESD in most cases without encountering the difficulties associated with conventional ESD.