Novel perfusion system using continuous liquid-suction catheter attachment in colorectal endoscopic submucosal dissection with water pressure method (with video).

Water pressure method (WPM) is useful for colorectal endoscopic submucosal dissection (ESD), characterized not only by underwater conditions but also by active water pressure via the waterjet function. However, the extension of the colorectum by injecting excess water and contaminating the operative field by stool and bleeding have been issues. This study aimed to evaluate the feasibility of a novel perfusion system using a continuous liquid-suction catheter attachment (CLCA) in colorectal ESD with WPM. We retrospectively reviewed cases in which the perfusion system was used in colorectal ESD with WPM between August 2022 and September 2023. We evaluated clinical characteristics, treatment outcomes, volume of injection by the waterjet function, volume of suction by the endoscope and CLCA, and concentration of floating matter in the operative field over time. Thirty-one cases were enrolled. The median lesion size was 30 (range, 15-100) mm. In all cases, en bloc resection was achieved without perforation. The median injection volume was 2312 (range, 1234-13,866) g. The median suction volumes by the endoscope and CLCA were 918 (range, 141-3162) and 1147 (range, 254-11,222) g, respectively. The median concentration of floating matter in the operative field (measured in 15 cases) was 15.3 (range, 7.3-112) mg/mL when the endoscope arrived at the lesion and 8.0 (range, 3.2-16) mg/mL after endoscopically washing at the beginning of the ESD. It ranged from 7.6 to 13.4 mg/dL every 20 min during ESD. This perfusion system could prevent the extension of the lumen and maintain a good field of view in colorectal ESD with WPM.

Multicenter retrospective analysis of complications and risk factors in endoscopic resection for esophageal cancer across Japan.

BACKGROUND: Endoscopic resection (ER) is a minimally invasive treatment for esophageal cancer that sometimes causes complications. To understand the real-world incidence and risk factors for these complications, a nationwide survey was conducted across Japan. METHODS: This retrospective multicenter study included patients who underwent ER for esophageal cancer from April 2017 to March 2018 (2017 complication analysis) and April 2021 to March 2022 (2021 complication analysis). The study assessed the complication rates and conducted risk factor analyses for endoscopic submucosal dissection (ESD) using data for these patients, with exclusions based on specific criteria to ensure data accuracy. RESULTS: In the 2021 complication analysis, there were two mortalities highly likely attributable (0.03%) to ER and one mortality possibly attributable (0.01%) to ER. Intraoperative perforation, delayed bleeding, and pneumonia occurred in 137 cases (1.8%), 44 cases (0.6%), and 130 cases (1.7%), respectively. In the multivariate analysis for complications after ESD, low ER volume of the facility was an independent risk factor for perforation, while lesion location in the cervical or upper thoracic esophagus was an independent factor for reduced risk of perforation. Age ≥ 80 years was a risk factor for pneumonia, while use of traction techniques was a factor for reduced risk of pneumonia. Lesions located in the middle thoracic esophagus had a lower risk of stricture, and the risk of stricture increased as the circumferential extent of the lesion increased. CONCLUSIONS: This large-scale study provided detailed insights into the complications associated with esophageal ER and identified significant risk factors.

Efficacy and safety of the water pressure method for endoscopic submucosal dissection in superficial pharyngeal cancer.

Background and study aims Superficial pharyngeal cancers can be cured with transoral surgery (TOS), which preserves organ function and quality of life. Pharyngeal endoscopic submucosal dissection (ESD) is challenging to perform because of limited maneuverability and complex anatomical features. The water pressure method (WPM) is useful for natural traction techniques during ESD and is potentially useful for pharyngeal ESD. This study aimed to investigate the short-term outcomes of WPM-ESD for pharyngeal lesions. Patients and methods Therapeutic outcomes of patients who underwent WPM-ESD for pharyngeal lesions at Keio University between May 2019 and February 2022 were retrospectively analyzed. Results Twenty-one pharyngeal lesions treated with WPM-ESD were analyzed. Three lesions were located in the oropharynx and 18 in the hypopharynx. All ESD procedures were performed under general anesthesia. The endoscopic en bloc resection rate was 100%. The median procedure time was 15 minutes (range 4-45 minutes). All patients were successfully extubated on the day of ESD. No serious adverse events (AEs) related to WPM-ESDs were observed. None of the patients required nasogastric intubation, percutaneous endoscopic gastrostomy, or tracheotomy. The median fasting time and hospital stay were 2 days (range 2-5 days) and 6 days (range 6-10 days), respectively. All the histological results indicated squamous cell carcinoma. The complete histologic resection rate was 76.2%. Conclusions WPM-ESD achieved a high en bloc resection rate and short procedure time without serious AEs. Thus, it may be a useful treatment for pharyngeal lesions.

Novel quantitative assessment indicators for efficiency and precision of endoscopic submucosal dissection in animal training models by analyzing an electrical surgical unit.

OBJECTIVES: Although endoscopic submucosal dissection (ESD) training is important, quantitative assessments have not been established. This study aimed to explore a novel quantitative assessment system by analyzing an electrical surgical unit (ESU). METHODS: This was an ex vivo study. Step one: to identify the novel efficiency indicators, 20 endoscopists performed one ESD each, and we analyzed correlations between their resection speed and electrical status. Step two: to identify the novel precision indicators, three experts and three novices performed one ESD each, and we compared the stability of the electrical status. Step three: three novices in step two performed 19 additional ESDs, and we analyzed the learning curve using novel indicators. RESULTS: Step one: the percentage of total activation time (AT) of ESU in the procedure time (ß coefficient, 0.80; P < 0.01) and AT required for submucosal dissection (ß coefficient, -0.57; P < 0.01) were significantly correlated with the resection speed. Step two: coefficient of variation of the AT per one pulse (0.16 [range, 0.13-0.17] vs. 0.26 [range, 0.20-0.41], P = 0.049) and coefficient of variation of the peak electric power per pulse during mucosal incision (0.14 [range, 0.080-0.15] vs. 0.25 [range, 0.24-0.28], P = 0.049) were significantly lower in the experts than in the novices. Regarding the learning curve, the percentage of total AT of ESU in the procedure time and AT required for submucosal dissection had a trend of improvement. CONCLUSION: Novel indicators identified by analyzing ESU enable quantitative assessment for endoscopist's skill.

Resectability of Small Duodenal Tumors: A Randomized Controlled Trial Comparing Underwater Endoscopic Mucosal Resection and Cold Snare Polypectomy.

INTRODUCTION: Underwater endoscopic mucosal resection (UEMR) and cold snare polypectomy (CSP) are novel endoscopic procedures for superficial nonampullary duodenal epithelial tumors (SNADET). However, consensus on how to use both procedures appropriately has not been established. In this study, we evaluated treatment outcomes of both procedures, including resectability. METHODS: In this single-center randomized controlled study conducted between January 2020 and June 2022, patients with SNADET ≤12 mm were randomly allocated to UEMR and CSP groups. The primary end point was sufficient vertical R0 resection (SVR0), which was defined as R0 resection including a sufficient submucosal layer. We compared treatment outcomes including SVR0 rate between groups. RESULTS: The SVR0 rate was significantly higher in the UEMR group than in the CSP group (65.6% vs 41.5%, P = 0.01). By contrast, the R0 resection rate was not significantly different between study groups (70.3% vs 61.5%, P = 0.29). The submucosal layer thickness was significantly greater in the UEMR group than in the CSP group (median 546 [range, 309-833] µm vs 69 [0-295] µm, P < 0.01). CSP had a shorter total procedure time (median 12 [range, 8-16] min vs 1 [1-3] min, P < 0.01) and fewer total bleeding events (9.4% vs 1.5%, P = 0.06). DISCUSSION: UEMR has superior vertical resectability compared with CSP, but CSP has a shorter procedure time and fewer bleeding events. Although CSP is preferable for most small SNADET, UEMR should be selected for lesions that cannot be definitively diagnosed as mucosal low-grade neoplasias.

Prospective cross-organ analysis for the causes of fever and increased inflammatory response after endoscopic resection.

OBJECTIVES: Fever and increased inflammatory responses sometimes occur following endoscopic resection (ER). However, the differences in causes according to the organ are scarcely understood, and several modified ER techniques have been proposed. Therefore, we conducted a comprehensive prospective study to investigate the cause of fever and increased inflammatory response across multiple organs after ER. METHODS: We included patients who underwent gastrointestinal endoscopic submucosal dissection (ESD) and duodenal endoscopic mucosal resection at our hospital between January 2020 and April 2022. Primary endpoints were fever and increased C-reactive protein (CRP) levels following ER. The secondary endpoints were risk factors for aspiration pneumonia. Blood tests and radiography were performed on the day after ER, and computed tomography was performed if the cause was unknown. RESULTS: Among the 822 patients included, aspiration pneumonia was the most common cause of fever and increased CRP levels after ER of the upper gastrointestinal tract (esophagus, 53%; stomach, 48%; and duodenum, 71%). Post-ER coagulation syndrome was most common after colorectal ESD (38%). On multivariate logistic regression analysis, lesions located in the esophagus (odds ratio [OR] 3.57; P < 0.001) and an amount of irrigation liquid of ≥1 L (OR 3.71; P = 0.003) were independent risk factors for aspiration pneumonia. CONCLUSIONS: Aspiration pneumonia was the most common cause of fever after upper gastrointestinal ER and post-ER coagulation syndrome following colorectal ESD. Lesions in the esophagus and an amount of irrigation liquid of ≥1 L were independent risk factors for aspiration pneumonia.

Decreased expression of TFF2 and decreased αGlcNAc glycosylation are malignant biomarkers of pyloric gland adenoma of the duodenum.

Pyloric gland adenoma (PGA) is a duodenal neoplasm expressing MUC6 and is often associated with high-grade dysplasia and adenocarcinoma. MUC6 secreted from the pyloric gland cells carries unique O-glycans exhibiting terminal α1,4-linked N-acetylglucosamine residues (αGlcNAc). The small peptide trefoil factor 2 (TFF2) is also secreted from pyloric gland cells and binds to αGlcNAc. We recently demonstrated that αGlcNAc serves as a tumor suppressor for gastric neoplasm including PGA, but the significance of TFF2 expression remains unknown. We examined 20 lesions representing low- and high-grade PGA in 22 cases by immunohistochemistry for αGlcNAc, TFF2, MUC6, MUC5AC, MUC2 and p53. αGlcNAc, TFF2 and MUC6 were co-expressed on the cell surface and a dot-like pattern in the cytosol in low-grade PGA lesions. High-grade PGA also expressed MUC6, but reduced αGlcNAc and TFF2 expression. The ratios of αGlcNAc or TFF2 to MUC6 score in high-grade PGA were significantly lower than low-grade PGA (P < 0.001). Co-expression of αGlcNAc-glycosylated MUC6 and TFF2 in PGA suggests the existence of αGlcNAc/TFF2 form complex in PGA cells, a finding consistent with our observations in non-neoplastic Brunner's gland cells. The decreased αGlcNAc and TFF2 expression are associated with high grade atypical cells, indicative of the malignant potential of PGA.

Effectiveness of water pressure method in colorectal endoscopic submucosal dissection by novice endoscopists.

Background and study aims Colorectal endoscopic submucosal dissection (ESD) remains challenging for novice endoscopists. Not only the underwater conditions but also active use of water pressure with the water pressure method (WPM) can help widen the submucosal layer. This study aimed to clarify the usefulness of WPM in colorectal ESD, especially for novice endoscopists. Methods This study was ex vivo and enrolled three novices. Each endoscopist performed conventional ESD (C-ESD) and ESD with WPM (WPM-ESD) 10 times on an excised bovine rectum. The treatment outcomes were compared between the two groups. Results Median procedure time was significantly shorter in the WPM-ESD group than in the C-ESD group (54 minutes, interquartile range [IQR] 42-67 vs. 45 minutes, IQR 34-55, P = 0.035). Although no significant difference in the activation time of electrical surgical unit (ESU) during the procedure was noted, the interval time during the procedure at which the ESU was not activated was significantly shorter in the WPM-ESD group (52 minutes, IQR 40-65 vs. 42 minutes, IQR 32-52, P = 0.030) than in the C-ESD group. Moreover, the time required for the endoscope to enter the submucosa was significantly shorter in the WPM-ESD group than in the C-ESD group (8.0 minutes, IQR 6.0-10 vs. 5.0 minutes, IQR 3.0-6.0, P < 0.001). Conclusions The present study reveals that the WPM method significantly shortens the procedure times for novices in colorectal ESD, especially the interval time, which refers to the time spent creating the field of view, and the time required for the endoscope to enter the submucosa.

Intensive endoscopic resection strategy for multiple duodenal polyposis associated with familial adenomatous polyposis.

BACKGROUND AND AIM: Multiple duodenal polyposis associated with familial adenomatous polyposis (FAP) is a high risk of duodenal cancer development. We evaluated the feasibility of intensive endoscopic resection that is a comprehensive treatment strategy combining multiple kinds of endoscopic treatments. METHODS: This is a retrospective observational study. From January 2012 to July 2022, a total of 28 consecutive patients in FAP who underwent endoscopic resection for multiple duodenal polyposis more than twice were included. Various endoscopic treatments, such as cold polypectomy (CP), endoscopic mucosal resection (EMR), underwater EMR (UEMR), endoscopic submucosal dissection (ESD), and endoscopic papillectomy (EP), were applied depending on lesions size and location. We evaluated individual information from patients' medical records, including patient characteristics, lesion characteristics, details of endoscopic treatment, pathologic findings, and Spigelman index (SI). We compared the differences in the number of treatments and observation periods with and without SI decrease. RESULTS: A total of 1040 lesions were removed by 138 sessions of endoscopic resections. The median follow-up period was 3.2 years. At the beginning of the endoscopic intervention, median SI was 9 (6-11) and the proportion of Spigelman stage (SS) IV was 61%. Repeated endoscopic treatments finally reduced SI in 26 patients (93%), and the proportion of SS IV significantly decreased to 13% with every endoscopic treatment. The mean SI change was -4.2 points per year (95% confidence interval: -0.6 to -5.9). There were no patients required surgical duodenectomy during the follow-up period. CONCLUSION: Intensive resection has a potential of downstaging duodenal lesions associated with FAP.

Endoscopic resection for local residual or recurrent cancer after definitive chemoradiotherapy or radiotherapy for esophageal squamous cell carcinoma.

Chemoradiotherapy (CRT) and radiotherapy (RT) are treatment options for esophageal squamous cell carcinoma (ESCC), but local residual/recurrent cancer after CRT/RT is a major problem. Endoscopic resection (ER) is an effective treatment option for local residual/recurrent cancer. To ensure the efficacy of ER, complete removal of endoscopically visible lesions with cancer-free vertical margins is desired. This study aimed to identify the endoscopic parameters associated with the complete endoscopic removal of local residual/recurrent cancer. In this single-center, retrospective study, we used a prospectively maintained database to identify esophageal lesions that were diagnosed as local residual/recurrent cancer after CRT/RT and treated by ER between January 2012 and December 2019. We evaluated the associations of endoscopic R0 resection with findings on conventional endoscopy and endoscopic ultrasonography (EUS). In total, 98 lesions (83 cases) were identified from our database. The rate of endoscopic R0 resection was higher for flat lesions (100% versus 77%, P = 0.00014). EUS was performed for 24 non-flat lesions, and endoscopic R0 resection was achieved for 94% of lesions with an uninterrupted fifth layer. Flat lesions on conventional endoscopy and lesions with an uninterrupted fifth layer on EUS are good candidates for ER.

First clinical experience with esophageal ESD using a novel adjustable traction device.

Background and study aims In esophageal endoscopic submucosal dissection (ESD), the effectiveness of traction including clip-thread method has been reported, but it is difficult to adjust the direction of traction. Therefore, we developed a dedicated over-tube type traction device (ENDOTORNADO) that has a working channel and allows traction from any directions by rotating itself. We investigated the clinical feasibility and potential usefulness of this new device in esophageal ESD. Patients and methods This was a single-center, retrospective study. Six cases of esophageal ESD with ENDOTORNADO from January to March 2022 (tESD group) were compared with 23 cases of conventional esophageal ESD performed by the same operator from January 2019 to December 2021 (cESD group) in terms of clinical treatment outcomes. Results In all cases, en bloc resection was achieved without intraoperative perforation. The total procedure speed was significantly increased in tESD group (23 vs. 30 mm 2 /min, P  = 0.046). In particular, the submucosal dissection time was significantly reduced to about one-quarter in tESD group (11 vs. 42 min, P  = 0.004). Conclusions ENDOTORNADO creates the adjustable traction from any directions and may have the clinical feasibility. It would be an option for human esophageal ESD.

Colorectal endoscopic submucosal dissection using the water pressure method for diverticulum-associated lesions: A case series study (with video).

Background and study aims Colorectal endoscopic submucosal dissection (ESD) of diverticulum-associated lesions is challenging because these lesions require precise excision in narrow spaces. The water pressure method (WPM) uses active water pressure by the waterjet function under saline solution-filled conditions. This study aimed to determine the feasibility of WPM for resection of diverticulum-associated lesions. Patients and methods This was a retrospective, observational case series study. We reviewed diverticulum-associated lesions treated by ESD with WPM at our institution between June 2017 and July 2021. Diverticulum-associated lesions were classified as follows: type 1, lesions in contact with or within 3 mm of the edge of a diverticulum; type 2, lesions that partially infiltrated the interior of a diverticulum; and type 3, lesions that infiltrated the interior of and completely covered the diverticulum. We collected data on the clinical characteristics and outcomes of the lesions. Results Seven diverticulum-associated lesions were treated with ESD using WPM. The median lesion size was 37 mm (interquartile range: 25-54 mm). There were three cases of type 1, three cases of type 2, and one case of type 3. Three lesions were resected circumventing the diverticulum, and four lesions involved resection of the diverticulum. The en bloc resection and R0 resection rates were 86 %. One patient had severe fibrosis, which caused perforation, and in another patient, the diverticulum was too deep and narrow to be completely isolated. Conclusions WPM allowed for precise procedures in the diverticulum. The feasibility of WPM has been suggested for diverticulum-associated lesions, although cases have been complex.

Predictors of stricture after non-circumferential endoscopic submucosal dissection of the esophagus and single-dose triamcinolone injection immediately after the procedure.

BACKGROUND AND AIMS: Local triamcinolone (TA) injection is widely used to prevent stricture formation after endoscopic submucosal dissection (ESD). However, stricture develops in up to 45% of patients despite this prophylactic measure. We therefore conducted a single-center prospective study to identify predictors of stricture after esophageal ESD and local TA injection. METHODS: Patients who underwent esophageal ESD and local TA injection and who were comprehensively assessed for lesion- and ESD-related factors were included in the study. Multivariate analyses were conducted to identify the predictors of stricture. RESULTS: A total of 203 patients were included in the analysis. Multivariate analysis identified residual mucosal width ≤5 mm (odds ratio [OR], 29.0; P < .0001) or 6 to 10 mm (OR, 3.7; P = .04), history of chemoradiotherapy (OR, 5.1; P = .045), and tumor in the cervical or upper thoracic esophagus (OR, 3.8; P = .018) as independent predictors of stricture. Based on the ORs of the predictors, patients were stratified into 2 groups according to stricture risk: patients in the high-risk group (residual mucosal width ≤5 mm or 6-10 mm with another predictor) had a stricture rate of 52.5% (31 of 59 cases), and patients in the low-risk group (residual mucosal width ≥11 mm or 6-10 mm without other predictors) had a stricture rate of 6.3% (9 of 144 cases). CONCLUSIONS: We identified predictors of stricture after ESD and local TA injection. Local TA injection prevented stricture formation after ESD in low-risk patients but was not sufficient to prevent stricture in high-risk patients. Additional interventions should thus be considered in high-risk patients. (University Hospital Medical Network Clinical Trials Registry number: UMIN 000028894.).

Modified double-layered suturing for a mucosal defect after colorectal endoscopic submucosal dissection (Origami method) (with video).

BACKGROUND AND AIMS: Through-the-scope clips (TTSCs) are among the most common devices used to close colorectal post-endoscopic submucosal dissection (ESD) defects. Although TTSCs are easy to deliver, even to the proximal colon, simple clipping of large defects results in mucosa-mucosa closure, which could be unreliable. We developed a novel endoscopic closure technique using a modified double-layered suturing called the origami method (OGM). This method closes not only the mucosal layer but also the muscle layer with only TTSCs, which can obtain robust closure even for large defects. This study aimed to evaluate the feasibility of this new closure method for colorectal post-ESD defects. METHODS: This retrospective observational study was conducted at a tertiary care hospital. We reviewed the cases of the OGM attempted after colorectal ESD at our institute between October 2021 and October 2022 and measured the clinical characteristics and outcomes of enrolled cases. RESULTS: The OGM was attempted in 47 cases after colorectal ESD. Thirty-one cases (66%) were in the proximal colon, 5 (11%) in the distal colon, 6 (13%) in the upper rectum, and 5 (10%) in the lower rectum. The median defect size was 38 mm, with the largest being 85 mm. Complete closure was achieved in 44 cases (94%), including all lower rectum cases. No perforations were caused by clips during closure, and delayed perforation and bleeding were not observed. CONCLUSIONS: This new closure method is feasible and recommended. The OGM could achieve reliable closure of large defects in any location, including the proximal colon and thick-walled lower rectum, using only TTSCs.

Novel closure method for a large mucosal defect after endoscopic resection: String clip suturing method with an anchor.

Duodenal endoscopic submucosal dissection (ESD) is a high-risk technique; however, prophylactic closure of mucosal defects reduces the risk. Unfortunately, we have encountered cases where closure is difficult, especially in large lesions. Therefore, we developed a novel closure technique, a string clip suturing method with an anchor (SCSM-A). This study aimed to elucidate the feasibility of this method. Five patients underwent this method for the closure of mucosal defects after duodenal ESD. The initial string clip was deployed at the anal end of the mucosal defects and the second clip was deployed at the other end of the mucosal defect. A third clip was deployed on the muscular layer in the middle of the mucosal defect. The free end of the string was pulled, and additional clips were deployed around the first to the third clips for complete closure. Because of grasping the muscle layer, SCSM-A can be employed for secure closure without creating a pocket. We reviewed the background and clinical course of hospitalization of patients who underwent this method. The resected specimens ranged from 52 to 103 mm in diameter. Complete closure of the mucosal defects was possible in all the cases. There were no adverse events, and no cases required additional treatment. All the patients were discharged within 7 days. The new method achieved secure closure even for large mucosal defects after duodenal ESD. This is a technique that can be applied to other organs, e.g., the colon.

Diagnostic value of endoscopic ultrasonography for the depth of gastric cancer suspected of submucosal invasion: a multicenter prospective study.

BACKGROUND: Although the combination of conventional endoscopy (CE) and endoscopic ultrasonography (EUS) is useful for predicting the depth of early gastric cancer (EGC), the diagnostic value of EUS for submucosal (SM) invasive cancer has not been fully investigated. METHODS: We conducted a multicenter prospective study from May 2017 to January 2021 to evaluate the validity of a diagnostic strategy combining CE and EUS and to clarify the additional value of EUS for EGC suspected of SM invasion. In each case, the diagnosis was first made using CE, followed by EUS, and finally confirmed using a combination algorithm. RESULTS: A total of 180 patients with EGC were enrolled from 10 institutions, of which 175 were analyzed. The histopathological depths were M, SM1, SM2, and ≥ MP in 72, 16, 64, and 23 lesions, respectively. Treatment included 92 endoscopic submucosal dissection cases and 83 surgical cases. The overall diagnostic accuracy classified by M-SM1 or SM2-MP was 58.3% for CE, 75.7% for EUS, and 78.9% for the combination of CE and EUS; the latter two were significantly higher than that of CE alone (P < 0.001). The CE, EUS, and combination accuracy rates in 108 differentiated-type lesions were 51.9%, 77.4%, and 79.6%, respectively; the latter two were significantly higher than CE alone (P < 0.001). A significant additive effect of EUS was observed in CE-SM2 low-confidence lesions but not in CE-M-SM1 lesions or in CE-SM2 high-confidence lesions. Among the nine CE findings, irregular surface, submucosal tumor-like elevation, and non-extension signs were significant independent markers of pSM2-MP. Poorly delineated EUS lesions were misdiagnosed. CONCLUSIONS: EUS provides additional value for differentiated-type and CE-SM2 low-confidence EGCs in diagnosing invasion depth. CLINICAL REGISTRATION NUMBER: UMIN000025862.

Closure of large mucosal defects for prevention of strictures after duodenal endoscopic submucosal dissection (with video).

BACKGROUND AND AIMS: Although lesions occupying a large circumference are associated with the risk of post-endoscopic submucosal dissection (ESD) strictures, the corresponding data for duodenal lesions are unknown. We aimed to analyze the incidence of post-ESD strictures after wide-field duodenal ESD. METHODS: In this retrospective study of duodenal lesions treated with ESD between July 2010 and August 2021, we included lesions that resulted in mucosal defects occupying more than half of the circumference and excluded lesions located in bulbs and involving Vater's papilla. We analyzed the incidence rates of stricture and luminal narrowing, in addition to bleeding and perforation as the outcomes in this study. Stricture was defined as the inability of the endoscope to pass through the lumen. A single endoscopist reviewed all endoscopic images and judged the degree of luminal narrowing. RESULTS: Eighty lesions were included, of which 2 involved mucosal defects occupying more than 90% of the circumference. The wound was closed, at least partially, in 90% in all lesions and in 86% of lesions with a mucosal defect occupying more than 75% of the circumference. None of the lesions caused delayed perforation and stricture, whereas 2 lesions caused delayed bleeding. Only 6 lesions caused luminal narrowing. When examined by the degree of closure, the rate of luminal narrowing increased with complete closure, incomplete closure, and nonclosure (4.9%, 9.1%, and 25.0%, respectively). CONCLUSIONS: Suturing may prevent post-ESD bleeding and perforation as well as stricture formation in cases of duodenal tumors, with mucosal defects occupying a large circumference.