Background/Aims: The efficacy of endoscopic submucosal dissection (ESD) for early-stage gastric cancer is well established. However, its acquisition is challenging owing to its complexity. In Japan, G-Master is a novel ex vivo gastric ESD training model. The effectiveness of training using G-Master is unknown. This study evaluated the efficacy of gastric ESD training using the G-Master to evaluate trainees’ learning curves and performance. Methods: Four trainees completed 30 ESD training sessions using the G-Master, and procedure time, resection area, resection completion, en-bloc resection requirement, and perforation occurrence were measured. Resection speed was the primary endpoint, and learning curves were evaluated using the Cumulative Sum (CUSUM) method. Results: All trainees completed the resection and en-bloc resection of the lesion without any intraoperative perforations. The learning curves covered three phases: initial growth, plateau, and late growth. The transition from phase 1 to phase 2 required a median of 10 sessions. Each trainee completed 30 training sessions in approximately 4 months. Conclusions Gastric ESD training using the G-Master is a simple, fast, and effective method for pre-ESD training in clinical practice. It is recommended that at least 10 training sessions be conducted.

Background/Aims: The efficacy of endoscopic submucosal dissection (ESD) for early-stage gastric cancer is well established. However, its acquisition is challenging owing to its complexity. In Japan, G-Master is a novel ex vivo gastric ESD training model. The effectiveness of training using G-Master is unknown. This study evaluated the efficacy of gastric ESD training using the G-Master to evaluate trainees’ learning curves and performance. Methods: Four trainees completed 30 ESD training sessions using the G-Master, and procedure time, resection area, resection completion, en-bloc resection requirement, and perforation occurrence were measured. Resection speed was the primary endpoint, and learning curves were evaluated using the Cumulative Sum (CUSUM) method. Results: All trainees completed the resection and en-bloc resection of the lesion without any intraoperative perforations. The learning curves covered three phases: initial growth, plateau, and late growth. The transition from phase 1 to phase 2 required a median of 10 sessions. Each trainee completed 30 training sessions in approximately 4 months. Conclusions Gastric ESD training using the G-Master is a simple, fast, and effective method for pre-ESD training in clinical practice. It is recommended that at least 10 training sessions be conducted.

Background/Aims: The efficacy of endoscopic submucosal dissection (ESD) for early-stage gastric cancer is well established. However, its acquisition is challenging owing to its complexity. In Japan, G-Master is a novel ex vivo gastric ESD training model. The effectiveness of training using G-Master is unknown. This study evaluated the efficacy of gastric ESD training using the G-Master to evaluate trainees’ learning curves and performance. Methods: Four trainees completed 30 ESD training sessions using the G-Master, and procedure time, resection area, resection completion, en-bloc resection requirement, and perforation occurrence were measured. Resection speed was the primary endpoint, and learning curves were evaluated using the Cumulative Sum (CUSUM) method. Results: All trainees completed the resection and en-bloc resection of the lesion without any intraoperative perforations. The learning curves covered three phases: initial growth, plateau, and late growth. The transition from phase 1 to phase 2 required a median of 10 sessions. Each trainee completed 30 training sessions in approximately 4 months. Conclusions Gastric ESD training using the G-Master is a simple, fast, and effective method for pre-ESD training in clinical practice. It is recommended that at least 10 training sessions be conducted.

Background/Aims: Leucine-rich α-2-glycoprotein (LRG) is a new serum biomarker reflecting the disease activity of ulcerative colitis (UC), but its change during the acute phase has not been enough investigated. Methods: Patients with UC who initiated the induction therapy with steroid or advanced therapy (biologics or Janus kinase inhibitors) were prospectively enrolled. Associations of LRG, C-reactive protein (CRP) and fecal calprotectin (FC) at baseline, week 1, and week 8 with clinical remission at week 8 and subsequent endoscopic improvement within 1 year (Mayo endoscopic subscore of 0 or 1) were assessed. Results: A total of 143 patients with UC were included. LRG and CRP at week 1 were significantly lower in the clinical remission group than in the non-remission group (LRG, 20.6 μg/mL vs. 28.4 μg/mL, P< 0.001; CRP, 0.9 mg/dL vs. 2.3 mg/dL, P< 0.001) while FC demonstrated the difference between groups only at week 8. The area under the curves of week 1 LRG, CRP, and FC for week 8 clinical remission using the receiver operating characteristic curves analysis were 0.68, 0.71, and 0.57, respectively. Furthermore, LRG and CRP predicted subsequent endoscopic improvement as early as week 1, while FC was predictive only at week 8. Conclusions LRG can be an early-phase biomarker predicting subsequent clinical and endoscopic response to induction therapy.

Background/Aims: Many Japanese institutions use electromagnetic extracorporeal shock wave lithotripsy (ESWL) systems for treating pancreatic duct stones. However, there are no reports on direct comparisons between recent electromagnetic lithotripters. This study aimed to verify whether the new electromagnetic lithotripter can improve the efficiency of pancreatic stone fragmentation, and to clarify the role of combined endoscopic treatment on the clearance of pancreatic duct stones. Methods: We retrospectively identified 208 patients with pancreatolithiasis who underwent endoscopic adjunctive treatment after pancreatic ESWL at a single Japanese center over a 17-year period. We evaluated the outcome data of this procedure performed with SLX-F2 (last 2 years; group A) and Lithostar/Lithoskop (first 15 years; group B), as well as additional endoscopic treatments for pancreatolithiasis. We also performed logistic regression analysis to detect various factors associated with the procedure. Results: For pancreatic head stones, ESWL disintegration was achieved in 93.7% of group A patients and 69.0% of group B patients (p=0.004), and adjunctive endoscopic treatment removed stones in 96.8% of group A patients and 73.0% of group B patients (p=0.003). Multivariate analysis revealed that lithotripter type (odds ratio, 6.99; 95% confidence interval, 1.56 to 31.33; p<0.01) and main pancreatic duct stricture (odds ratio, 2.87; 95% confidence interval, 1.27 to 6.45; p<0.01) were significant factors for ESWL fragmentation. Conclusions The SLX F2 showed high performance in fragmenting the pancreatic duct stones.In addition, endoscopic adjunctive treatment improved the overall success rate of the procedure. The improved ESWL lithotripter has many advantages for patients undergoing pancreatic lithotripsy treatment.

An appropriate post-polypectomy surveillance program requires the effectiveness of reducing colorectal cancer and safety. In addition, the post-polypectomy surveillance program should consider the burden of limited medical resource capacity, cost-effectiveness, and patient adherence. In this sense, a risk-stratified surveillance program based on baseline colonoscopy results is ideal. Major international guidelines for post-polypectomy surveillance, such as those from the European Union and the United States, have recommended risk-stratified surveillance programs. Both guidelines have recently been updated to better differentiate between high- and low-risk individuals. In both updated guidelines, more individuals have been downgraded to lower-risk groups that require less frequent or no surveillance. Furthermore, increased attention has been paid to the surveillance of patients who undergo serrated polyp removal. Previous guidelines in Japan did not clearly outline the risk stratification in post-polypectomy surveillance. However, the new colonoscopy screening and surveillance guidelines presented by the Japan Gastroenterological Endoscopy Society include a risk-stratified post-polypectomy surveillance program. Further discussion and analysis of unresolved issues in this field, such as the optimal follow-up after the first surveillance, the upper age limit for surveillance, and the ideal method for improving adherence to surveillance guidelines, are warranted.

Background/Aims: Probe-based confocal laser endomicroscopy (pCLE) requires the administration of intravenous (IV) fluorescein. This study aimed to determine the optimal dose of IV fluorescein for both upper and lower gastrointestinal (GI) tract pCLE. Methods: Patients 20 to 79 years old with gastric high-grade dysplasia (HGD) or colorectal neoplasms (CRNs) were enrolled in the study. The dose de-escalation method was employed with five levels. The primary endpoint of the study was the determination of the optimal dose of IV fluorescein for pCLE of the GI tract. The reduced dose was determined based on off-line reviews by three endoscopists. An insufficient dose of fluorescein was defined as the dose of fluorescein with which the pCLE images were not deemed to be visible. If all three endoscopists determined that the tissue structure was visible, the doses were de-escalated. Results: A total of 12 patients with gastric HGD and 12 patients with CRNs were enrolled in the study. Doses were de-escalated to 0.5 mg/kg of fluorescein for both non-neoplastic duodenal and colorectal mucosa. All gastric HGD or CRNs were visible with pCLE with IV fluorescein at 0.5 mg/kg. Conclusions In the present study, pCLE with IV fluorescein 0.5 mg/kg was adequate to visualize the magnified structure of both the upper and lower GI tract.

Background/Aims: Probe-based confocal laser endomicroscopy (pCLE) requires the administration of intravenous (IV) fluorescein. This study aimed to determine the optimal dose of IV fluorescein for both upper and lower gastrointestinal (GI) tract pCLE. Methods: Patients 20 to 79 years old with gastric high-grade dysplasia (HGD) or colorectal neoplasms (CRNs) were enrolled in the study. The dose de-escalation method was employed with five levels. The primary endpoint of the study was the determination of the optimal dose of IV fluorescein for pCLE of the GI tract. The reduced dose was determined based on off-line reviews by three endoscopists. An insufficient dose of fluorescein was defined as the dose of fluorescein with which the pCLE images were not deemed to be visible. If all three endoscopists determined that the tissue structure was visible, the doses were de-escalated. Results: A total of 12 patients with gastric HGD and 12 patients with CRNs were enrolled in the study. Doses were de-escalated to 0.5 mg/kg of fluorescein for both non-neoplastic duodenal and colorectal mucosa. All gastric HGD or CRNs were visible with pCLE with IV fluorescein at 0.5 mg/kg. Conclusions In the present study, pCLE with IV fluorescein 0.5 mg/kg was adequate to visualize the magnified structure of both the upper and lower GI tract.

This systematic review aimed to assess the efficacy of the current approach to tissue traction during the endoscopic submucosal dissection (ESD) of superficial esophageal cancer, early gastric cancer, and colorectal neoplasms.We performed a systematic electronic literature search of articles published in PubMed and selected comparative studies to investigate the treatment outcomes of tractionassisted versus conventional ESD. Using the keywords, we retrieved 381 articles, including five eligible articles on the esophagus, 13 on the stomach, and 12 on the colorectum. A total of seven randomized controlled tri-als and 23 retrospective studies were identified. Clip line traction and submucosal tunneling were effective in re-ducing the procedural time during esophageal ESD. The efficacy of traction methods in gastric ESD varied in terms of the devices and strategies used depending on the le-sion location and degree of submucosal fibrosis. Several prospective and retrospective studies utilized traction de-vices without the need to reinsert the colonoscope. When pocket creation is included, the traction devices and methods effectively shorten the procedural time during colorectal ESD. Although the efficacy is dependent on the organ and tumor locations, several traction techniques have been demonstrated to be efficacious in facilitating ESD by maintaining satisfactory traction during dissection.

Colorectal tumors with superficial submucosal invasion, which cannot be removed by snaring, are one of the most optimal indications for colorectal endoscopic submucosal dissection (ESD). Therefore, estimation of the invasion depth is the first key to successful colorectal ESD. Although estimation of the invasion depth based on the gross morphology may be useful in selected cases, its diagnostic accuracy could not reach the clinical requirement. The Japan Narrow-band Imaging (NBI) Expert Team (JNET) classification of NBI magnifying endoscopy findings is a useful method for histologic prediction and invasion depth estimation. However, magnifying chromoendoscopy is still necessary for JNET type 2B lesions to reach a satisfactory diagnostic accuracy. Endocytoscopy with artificial intelligence is a promising technology in invasion depth estimation; however, more data are needed for its clinical application.
Artificial Intelligence ; Classification ; Colonoscopy ; Colorectal Neoplasms ; Endoscopy ; Japan ; Methods ; Neoplasm Staging ; SNARE Proteins