Kingo Hirasawa

Introduction: This study aimed to evaluate the clinical outcomes of endoscopic resection for gastric muscularis propria-derived subepithelial lesions, including gastrointestinal stromal tumors, within a stepwise implementation program for endoscopic full-thickness resection (EFTR), and to identify factors associated with pathological R1 resection and technical difficulty. Methods: This retrospective single-center study included consecutive patients who underwent endoscopic muscularis dissection (EMD), endoscopic resection with one-port placement (EROPP), or pure EFTR between January 2017 and January 2026. These techniques were introduced sequentially but selected according to lesion characteristics, technical feasibility, and institutional experience. Clinicopathological characteristics, procedural outcomes, pathological resection status, adverse events, and long-term outcomes were analyzed. Technical difficulty was assessed using a composite definition incorporating prolonged treatment time, major adverse events, pathological R1 resection, and the use of multiple over-the-scope clips. Results: Seventy patients were included: 6 underwent EMD, 35 EROPP, and 29 pure EFTR. The median tumor size was 22 mm. Endoscopic complete resection was achieved in all patients, and pathological R0 resection in 62/70 (88.6%). Pathological R0 resection rates were 83.3%, 82.9%, and 96.5% for EMD, EROPP, and pure EFTR, respectively, with no significant difference among the three groups (P = 0.140). The median resection and closure times were 35 and 18 min, respectively. One major adverse event occurred: delayed perforation requiring endoscopic treatment. Larger tumor size was significantly associated with both pathological R1 resection and technical difficulty. During a median follow-up of 47 months for the entire cohort, no local recurrence or distant metastasis was observed. Conclusions: Endoscopic resection for selected gastric muscularis propria-derived tumors within a stepwise implementation program was associated with favorable long-term clinical outcomes. Tumor size was the principal factor associated with technical difficulty and pathological R1 resection. Pure EFTR provided favorable outcomes in appropriately selected lesions, while EROPP remained a complementary option for selected technically challenging lesions. These findings provide practical information for institutions considering the introduction of EFTR and support lesion-based procedural selection according to technical feasibility and institutional expertise.

Objectives: Endoscopic full‐thickness resection (EFTR) and laparoscopic and endoscopic cooperative surgery (LECS) are minimally invasive treatments for gastric submucosal tumors (SMTs). Because comparative data of both methods are lacking, we aimed to compare the clinical outcomes between EFTR and LECS for gastric SMT. Methods: This multicenter study included patients who underwent EFTR or LECS for gastric SMT in four Japanese institutions. A 1:1 propensity score matching (PSM) analysis was performed with a caliper width of 0.2. Covariates included age; sex; body mass index; history of abdominal surgery, cardiovascular disease, or cerebrovascular disease; comorbidities; smoking and drinking habits; antiplatelet and anticoagulant intake; along with tumor location, type, and size. Results: We enrolled 38 patients treated with EFTR and 59, with LECS. After PSM, 21 patients were selected. The histological R0 resection rate was comparable between EFTR and LECS before (95% vs. 100%) and after (91% vs. 100%) PSM. In the EFTR group, median operation time was shorter (93 min vs. 161 min, p < 0.001), median numbers of attending doctors were fewer (5 vs. 3, p < 0.001), with procedure (¥305,330 vs. ¥434,700, p = 0.017) and total hospitalization costs (¥676,400 vs. ¥861,420) lower than those in the LECS group after PSM. Adverse event rates were low (5% vs. 14%, p = 0.606) in both groups. Conclusions: EFTR and LECS provide efficacious oncological outcomes for patients with small (≤ 3 cm) intraluminal type gastric SMT. EFTR demonstrated favorable operative efficiency and economic outcomes, suggesting it may be a potentially cost‐effective alternative.

Objectives: Ulcerative colitis (UC)‐associated neoplasia (UCAN) carries a risk of metachronous development; however, risk stratification based on inflammatory origin remains unclear. This exploratory study aimed to classify UCAN arising in colitis‐affected areas and to evaluate long‐term outcomes after endoscopic resection (ER). Methods: We retrospectively analyzed the data of 102 patients with UC who underwent ER for colorectal neoplasia between 2004 and 2024. Lesions in colitis‐affected areas were operationally classified as confirmed UCAN, based on non‐polypoid morphology and characteristic p53 and Ki‐67 immunostaining patterns, or as probable UCAN. Lesions in colitis‐unaffected areas were classified as sporadic neoplasia (SN). Cumulative incidences of metachronous neoplasia and overall survival were estimated using the Kaplan–Meier method, and associations with metachronous confirmed UCAN were assessed using univariate Cox proportional hazards models. Results: The median follow‐up period was 4.3 years. Among 102 lesions, 13 were classified as confirmed UCAN, 68 as probable UCAN, and 21 as SN. The 5‐year cumulative incidence of metachronous confirmed UCAN was significantly higher in the confirmed UCAN group (52%) than in the probable UCAN (4%) and SN (0%) groups ( p < 0.01). Confirmed UCAN remained independently associated with metachronous confirmed UCAN (hazard ratio, 11.05; 95% confidence interval, 2.01–60.7; p < 0.01). Overall survival did not differ significantly among groups. Conclusions: Using an exploratory classification, confirmed UCAN was associated with an increased incidence of metachronous neoplasia after ER. These findings suggest that this subgroup may warrant closer surveillance; however, further validation is required.

Background: Underwater endoscopic mucosal resection (UEMR) is a relatively new treatment method for sporadic non-ampullary duodenal epithelial tumors (SNADETs), and its usefulness has been reported for SNADETs ≤ 20 mm. However, its effectiveness and safety compared with conventional endoscopic mucosal resection (CEMR) remain controversial. This study aims to assess the treatment outcomes and evaluate the beneficial effects and safety of UEMR for SNADETs ≤ 20 mm. Methods: This is an open-label, multicenter collaborative, non-inferiority randomized controlled trial with two parallel groups conducted across 40 institutions in Japan. The study subjects will be patients with SNADETs ≤ 20 mm. A total of 320 patients will be randomized to either the CEMR or UEMR group in a 1:1 allocation ratio. The primary endpoint is the 1-year recurrence-free survival rate, defined as the number of cases with no recurrence of SNADET or death from any cause within one year of EMR. The secondary endpoints include the en bloc resection rate, histological complete resection rate, adverse events, technical success rate, total procedure time, resection time, mucosal closure time, complete mucosal closure rate, complete mucosal closure rate with standard clips, 1-year duodenum preservation survival rate, and device cost. Discussion: This multicenter, open-label, randomized controlled trial (RCT) with 320 subjects aims to determine whether the 1-year recurrence-free survival rate of underwater endoscopic resection is not inferior to that of conventional endoscopic mucosal resection for SNADETs ≤ 20 mm. If the efficacy and safety of UEMR are proven in this RCT, it is expected to be recognized as the standard treatment for SNADETs ≤ 20 mm. Owing to the absence of submucosal injection, UEMR is a simpler and more cost-effective technique compared to CEMR and is anticipated to become the primary method of EMR.

Background/Aims: Endoscopic submucosal dissection (ESD) for superficial non-ampullary duodenal epithelial tumors (SNADETs) is technically challenging and is associated with a risk of adverse events, particularly when lesions are located near the major papilla. Pancreatic duct (PD) stent may reduce the risk of post-ESD pancreatitis; however, no standard strategy has been established. This study aimed to evaluate the effectiveness and safety of PD stent placement combined with ESD for SNADETs near the major papilla.Methods: This was a retrospective study of duodenal ESD after prophylactic PD stent placement in patients with SNADET near the major papilla at a university hospital between March 2014 and September 2023.Results: Four lesions were located within 5 mm of the major papilla, and seven within 5 to 10 mm. The median interval between stent placement and ESD was 2 days. The en bloc and R0 resection rates were 100% and 90.9%, respectively. No stent migration occurred during ESD, and all mucosal defects were completely closed using endoscopic clips. Delayed bleeding and post-ESD pancreatitis were observed in one and two cases, respectively.Conclusions: PD stent placement combined with ESD is an effective treatment strategy for SNADETs near the major papilla. However, the risk of post-ESD pancreatitis remains, indicating the need for further preventive strategies.

Background and Aim: Esophageal squamous cell carcinoma (ESCC) in patients with no history of tobacco smoking or alcohol consumption accounts for approximately 5% of all ESCCs. This study aimed to clarify the clinicopathological features of superficial ESCCs in patients with no history of tobacco smoking or alcohol consumption.Methods: Clinical data and pathological features of 108 superficial ESCCs in endoscopic submucosal dissection (ESD) specimens obtained from 102 patients with no history of tobacco smoking or alcohol consumption (NTNA group) were reviewed. For comparison, the clinicopathological features of 767 superficial ESCCs in ESD specimens from 544 patients with history of tobacco smoking and alcohol consumption (TA group) were also reviewed. Factors analyzed included age, sex, synchronous/metachronous cancer, gastroesophageal reflux disease (GERD), tumor size, tumor site, macroscopic type, Lugol‐voiding lesion (LVL) grade, invasion depth, and lymphovascular invasion. LVLs were graded as A (no lesions), B (1–9 lesions), and C (> 9 lesions).Results: The univariate analysis revealed that female predominance (p < 0.01), absence of synchronous/metachronous cancer (p < 0.01), grade A LVLs (p < 0.01), presence of GERD (p < 0.01), tumor location in the middle thoracic esophagus (p < 0.05), tumor location at the posterior wall (p < 0.05), and 0–IIa macroscopic type (p < 0.01) were significantly more frequently observed in NTNA group than in TA group. Multivariate analysis identified female predominance (OR 68.2, p < 0.001), LVL grade A (OR 50.6, p < 0.001), and 0–IIa macroscopic type (OR 7.2, p < 0.001) as significant features in the NTNA group.Conclusions: This study demonstrated the unique clinicopathological features of ESCCs in patients with NTNA.

Introduction: Endoscopic submucosal dissection (ESD) has become a widely adopted treatment for early esophageal cancer. However, extensive mucosal defects resulting from ESD pose a significant risk of post-procedural strictures. Despite efforts to prevent strictures through various means, including steroid administration, they remain a challenge, significantly impacting patients’ quality of life and healthcare costs. Thus, identifying risk factors for refractory strictures following entire circumferential esophageal ESD (EC-E-ESD) is imperative. Methods: Between July 2013 and September 2023, 49 patients who underwent EC-E-ESD were retrospectively analyzed. Patients were classified based on the presence of refractory or non-refractory strictures. A refractory stricture was defined as requiring six or more endoscopic balloon dilation procedures before stricture improvement. Clinicopathological features and outcomes were examined using multivariate logistic regression analysis. Results: Refractory strictures were observed in 51% of patients. A comparison showed that the refractory group had a significantly higher percentage of muscular injury (52% vs. 8%, p = 0.002) and mucosal defect length ≥50 mm (68% vs. 37%, p = 0.047) than the non-refractory group. Multivariate analysis showed that muscular injury (odds ratio 16.2; 95% confidence interval: 2.04–129.1) was an independent risk factor for refractory strictures after EC-E-ESD. Conclusions: Muscular injury during EC-E-ESD is a risk factor for refractory strictures. Strategies to prevent injury, such as meticulous dissection techniques and effective steroid administration, may mitigate this risk. However, current prophylactic measures are inadequate, highlighting the need for further research into preventive strategies.

Although endoscopic submucosal dissection (ESD) is widely accepted for colorectal tumors, ESD of tumors involving a diverticulum remains a challenge. In particular, the absence of a muscle layer in diverticula makes intraoperative perforation almost inevitable [1] [2]. Thus, reliable closure after ESD is crucial. Here, we report a case in which complete closure was achieved using a dual-action tissue (DAT) clip for a full-thickness defect after ESD of a tumor involving a colonic diverticulum. An 18 mm protruding lesion extended into a diverticulum in the ascending colon ([Fig. 1] a). ESD was performed under conscious sedation and using carbon dioxide insufflation. A small caliber transparent hood (DH-29CR; Fujifilm, Tokyo, Japan) was attached to the tip of the endoscope, and a 1.5-mm ESD knife (T-type Cutting Knife; Micro-Tech, Nanjing, China) was used for ESD. The water pressure technique was used to dissect the submucosa, and a multi-loop device was used for traction. Submucosal dissection was performed after completing the circumferential incision. When encountering the lesion extending into the diverticulum, a short myotomy was performed in front of the diverticulum to create a gap to enter the space below the diverticulum [3]. The short myotomy was followed by a muscular incision around the lesion, and the tissue beneath the diverticulum was resected ([Fig. 1] b, c). The lesion was resected in one piece. Following the completion of ESD, the full-thickness defect was closed using a DAT clip and ordinary endoscopic clips. The muscle layer was inverted and tightly closed using a DAT clip, resulting in complete defect closure ([Fig. 1] d–f; [Video 1]). The patient was discharged on postoperative day 3. A DAT clip enabled muscle layer inversion, allowing for secure and reliable layered closure using endoscopic clips. Endoscopy_UCTN_Code_CPL_1AJ_2AD_3AD Article published online: 08 December 2025 © 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

Background and Aim: Qualitative diagnosis of ulcerative colitis–associated neoplasia (UCAN) is crucial for surveillance colonoscopy in patients with ulcerative colitis (UC). Although the utility of magnifying endoscopy with narrow‐band imaging (ME‐NBI) in sporadic neoplasia diagnosis has been reported, its efficacy in UCAN remains unclear. This study aimed to evaluate the usefulness of ME‐NBI for qualitative diagnosis of UCAN.Methods: We generated 60 ME‐NBI images (30 UCANs and 30 nonneoplasia lesions, including 10 polypoid and 20 nonpolypoid lesions) from patients with UC who underwent colonoscopy at our hospital between 2015 and 2023. Eleven endoscopists (seven experts and four trainees) independently assessed these images. Lesions were categorized into high‐ (≥ 80%), moderate‐ (50%–79%), and low‐ (< 50%) accuracy groups on the basis of the correct diagnostic rate.Results: Overall sensitivity, specificity, and correct diagnostic rates were 66.5%, 79.0%, and 71.8%, respectively. Experts tended to exhibit higher specificity than trainees (83% vs. 70%). Polypoid lesions showed higher sensitivity (92% vs. 54%) and lower specificity (61% vs. 88%) than nonpolypoid lesions. Overall, the kappa value was 0.411. In UCAN, 37%, 37%, and 24% were classified into the high‐, moderate‐, and low‐accuracy groups, respectively. All endoscopists assessed one case of UCAN in the low‐accuracy group as a nonneoplastic vessel with a surface pattern. Only two nonneoplasias were identified as having nonneoplastic vessel and surface patterns by all endoscopists.Conclusions: This study demonstrated the usefulness of ME‐NBI for qualitative diagnosis, along with its limitations. A unique endoscopic diagnostic algorithm for UCAN, incorporating ME‐NBI and other modalities, is necessary.

Background and Aim: Superficial nonampullary duodenal epithelial tumors (SNADETs) that are pathologically classified as gastric‐type might manifest a more aggressive behavior than the intestinal type. However, the details of their histologic and genetic features remain unclear because of their rarity. This study was aimed at identifying clinicopathological findings and early genomic events in gastric‐type SNADETs treated with endoscopic resection. Methods: We retrospectively analyzed 204 patients with SNADETs between January 2011 and September 2020. Immunohistochemical analysis for β ‐catenin and targeted exome sequence analysis of 50 cancer‐related genes using next‐generation sequencing were performed for the representative cases. Results: Among the 204 SNADETs cases, only nine (4.4%) were gastric type; the remaining 195 cases were intestinal type. Among the gastric‐type tumors, seven were adenomas and two were adenocarcinomas, whereas only three of the 195 intestinal‐type tumors were adenocarcinomas. Nuclear expression of β ‐catenin was observed in three of the nine (33%) gastric‐type tumors and in eight of the 10 (80%) intestinal‐type tumors. The most prevalent abnormality among the 50 genes tested in gastric‐type tumors was GNAS mutation (89%), whereas that in intestinal‐type tumors was APC mutation (67%). All gastric‐type adenocarcinomas had GNAS mutations as well as adenomas, while APC mutations were absent in intestinal‐type adenocarcinomas and present in most adenomas. Conclusions: GNAS mutations are more common in gastric‐type SNADETs than in the intestinal type. As GNAS mutations are continuously present from adenoma to adenocarcinoma, resection at the adenoma stage is desirable.