Comparison of dissection speed during colorectal ESD between the novel Multiloop (M-loop) traction method and ESD methods without traction.

Background and study aims We previously reported on a novel traction method called Multiloop (M-loop) for faster colorectal endoscopic submucosal dissection (ESD). In this study, we retrospectively compared the difference in submucosal dissection time (SDT), and submucosal dissection speed (SDS) between groups of patients who were treated using traction with the M-loop method, and with non-traction methods of colorectal ESD. Patients and methods We reviewed and timed duration of colorectal ESD by the non-traction method from videos recorded between June 2016 and December 2017. From January 2018 onward, we used the M-loop method during all colorectal ESDs and timed it until August 2018. Outcomes of colorectal ESD with the M-loop method and non-traction methods were compared. The study involved two experts and eight non-experts and was carried out at a tertiary endoscopic center in Japan. Results The study included 50 patients who treated with the M-loop method and 115 patients treated with the non-traction method. Submucosal dissection time (SDT) was not significantly different (M-loop group, 42.1  ±â€Šâ€Š4.2 min, non-traction ESD group, 51.9 ±â€Š3.3 min) ( P  = 0.098), but submucosal dissection speed (SDS) was significantly greater (M-loop group, 28.0 ±â€Š2.9 mm 2  /min, non-traction ESD group, 19.9 ±â€Š2.0 mm 2 /min) ( P  = 0.0014) in the M-loop method group. Multivariate analysis showed that the M-loop method increased SDS by odds ratio of 1.46 ( P  = 0.001) when compared to the non-traction ESD method. A significant difference was also observed for SDT and SDS when the two methods were compared after propensity score matching ( P  = 0.001). No differences in unfavorable outcomes were observed. Conclusions The M-loop method improved SDS compared to non-traction methods of ESD. The method is an effective tool to assist colorectal ESD.

Multiloop as a novel traction method in accelerating colorectal endoscopic submucosal dissection.

BACKGROUND AND AIMS: Traction methods have been reported to speed up endoscopic submucosal dissection (ESD). We used the multiloop (M-loop) method as a traction method for colorectal ESD and recorded the submucosal dissection time (SDT) and submucosal dissection speed (SDS). METHODS: From January to August 2018, we used the M-loop method for colorectal ESD procedures and timed the duration and recorded the outcomes. Two experts and eight nonexperts performed the procedures, which were carried out at a tertiary endoscopic center in Japan. RESULTS: A total of 50 patients were treated by colorectal ESD using the M-loop method. The mean SDT was 42.1 ± 4.16 minutes and the mean SDS was 28.0 ± 2.89 mm2/minutes. The mean SDS was 38.9 ± 6.9 mm2/minutes for experts and 25.3 ± 3.1 mm2/minutes for nonexperts. En bloc resection was achieved in 100% of cases. There were 3 adverse events and unfavorable outcomes. CONCLUSIONS: Traction by the M-loop method improved SDS in colorectal ESD. The method can be an effective tool to assist colorectal ESD. Further evaluation of the usefulness of the M-loop method is required in direct comparison with conventional ESD.

Evaluation of an e-learning system for diagnosis of gastric lesions using magnifying narrow-band imaging: a multicenter randomized controlled study.

Background and study aim Magnifying narrow-band imaging (M-NBI) is useful for the accurate diagnosis of early gastric cancer (EGC). However, acquiring skill at M-NBI diagnosis takes substantial effort. An Internet-based e-learning system to teach endoscopic diagnosis of EGC using M-NBI has been developed. This study evaluated its effectiveness. Participants and methods This study was designed as a multicenter randomized controlled trial. We recruited endoscopists as participants from all over Japan. After completing Test 1, which consisted of M-NBI images of 40 gastric lesions, participants were randomly assigned to the e-learning or non-e-learning groups. Only the e-learning group was allowed to access the e-learning system. After the e-learning period, both groups received Test 2. The analysis set was participants who scored < 80 % accuracy on Test 1. The primary end point was the difference in accuracy between Test 1 and Test 2 for the two groups. Results A total of 395 participants from 77 institutions completed Test 1 (198 in the e-learning group and 197 in the non-e-learning group). After the e-learning period, all 395 completed Test 2. The analysis sets were e-learning group: n = 184; and non-e-learning group: n = 184. The mean Test 1 score was 59.9 % for the e-learning group and 61.7 % for the non-e-learning group. The change in accuracy in Test 2 was significantly higher in the e-learning group than in the non-e-learning group (7.4 points vs. 0.14 points, respectively; P < 0.001). Conclusion This study clearly demonstrated the efficacy of the e-learning system in improving practitioners' capabilities to diagnose EGC using M-NBI.Trial registered at University Hospital Medical Information Network Clinical Trials Registry (UMIN000008569).

Usefulness of dilated blood vessels in the tumor periphery for assessing the invasion depth of small-sized depressed colorectal cancer.

The relationship between dilated blood vessels in the tumor periphery and the tumor invasion depth is unclear. Therefore, the present study aimed to clarify the relationship between dilated blood vessels and the invasion depth of small-sized (<30 mm) colorectal cancer (CRC), and its implications on endoscopic treatment.We performed a single-arm observational study of the diagnostic accuracy of the existence of dilated vessels in the tumor periphery of CRC lesions as an indicator of submucosal deep (SM-d, ≥1000 µm) carcinomas. Lesions were classified into two groups based on the existence of dilated vessels by two experienced endoscopists. The clinicopathological features, invasion depth, and lymphovascular invasion/poorly differentiated clusters were analyzed in all resected specimens.Four hundred and two consecutive small-sized CRC lesions were included. The dilated vessels were observed in 96/402 (24%) lesions, and most of them (93/96) were found in depressed lesions. In depressed lesions, the histopathological diagnosis of the dilated vessels group showed SM-d or deeper invasion in 84/93 (90%) cases, whereas 3/20 (15%) had SM-d invasion in the nondilated vessels group (P < 0.001). When the dilated vessels were used as an indicator of SM-d or deeper invasion in depressed lesions, the sensitivity was 95.6%, specificity was 66.7%, and accuracy was 90.2%. No correlation was observed between the existence of dilated vessels and the lesion site, lesion diameter, and lymphovascular invasion/poorly differentiated cluster.The existence of dilated blood vessels in the tumor periphery suggests SM-d or deeper invasion in depressed lesions.