Ken Inoue

Background: Minimally invasive treatments for superficial pharyngeal cancer including transoral videolaryngoscopic surgery (TOVS) and endoscopic submucosal dissection (ESD) have become more widespread as minimally invasive treatments; however, no reports have compared these treatment methods. Methods: We retrospectively investigated consecutive patients with superficial hypopharyngeal squamous cell carcinoma who underwent ESD or TOVS between January 2013 and December 2024. Results: A total of 60 lesions in 55 patients were included in the ESD and TOVS groups. The en bloc resection rate was 100% in both groups. The R0 resection rate in the ESD group showed a nonsignificant trend toward being higher than that in the TOVS group (58.1% vs. 34.5%; p = 0.077). No significant differences were observed in the 3‐year overall survival (OS) rates between the TOVS and ESD groups (93.8% vs. 81.3%; p = 0.330). The 3‐year cumulative incidence of local recurrence was 13.6% in the TOVS group and 5.9% in the ESD group ( p = 0.241). In an exploratory univariate analysis, tumor thickness ≥ 1000 μm was significantly associated with lymph node metastasis ( p = 0.017). Conclusions: Clinical outcomes in patients with superficial hypopharyngeal cancer were not significantly different between ESD and TOVS. Although the cumulative incidence of local recurrence was numerically lower after ESD than after TOVS, the difference was not statistically significant. Both procedures may represent feasible minimally invasive treatment options for selected patients.

Endoscopic closure of mucosal defects after colorectal endoscopic submucosal dissection (ESD) has been increasingly adopted to prevent adverse events. Various devices and techniques, including conventional clips, clips with various technical tips, clip with line, clip with device, special clips, and suturing devices, have been developed, achieving high rates of complete closure (approximately 95% on average), although procedure times and technical complexity vary considerably. Among 14 eligible comparative studies, including randomized controlled trials and retrospective studies published up to April 2026, a meta-analysis was performed to evaluate the efficacy of complete closure after colorectal ESD in preventing delayed bleeding (DB), delayed perforation (DP), and post-ESD coagulation syndrome (PECS). For DB, pooled analysis demonstrated that complete endoscopic closure was significantly associated with a reduced risk of DB (odds ratio [OR]: 0.77, 95% confidence interval [CI]: 0.60–0.97, p = 0.030, I² = 53.6%). In contrast, no significant differences were observed between the closure and non-closure groups for DP (OR: 0.60, 95% CI: 0.23–1.55, p = 0.290, I² = 0.0%) or PECS (OR: 0.94, 95% CI: 0.65–1.38, p = 0.765, I² = 56.6%). In a literature review, reported risk factors for DB include lesion size >50 mm, an ASA score of III or IV, antithrombotic therapy, age ≥75 years, and rectal location. Severe fibrosis and prolonged ESD procedure time have been reported as risk factors for DP, whereas female sex, age ≥70 years, right-sided colon, and lesion size >24 mm have been associated with PECS. Overall, various closure devices and techniques achieve high technical success rates after colorectal ESD. Complete closure appears beneficial for reducing DB, particularly in high-risk patients, whereas its efficacy for preventing DP and PECS remains uncertain. Further studies are warranted.

Background and study aims: Post-endoscopic submucosal dissection (ESD) coagulation syndrome (PECS) is defined as abdominal pain with inflammatory responses, requiring careful differentiation from delayed perforation (DP). This study aimed to evaluate clinical and biochemical characteristics associated with PECS and DP following ESD, and to develop a scoring system for predicting PECS. Patients and methods: We retrospectively analyzed 318 consecutive patients who underwent colorectal ESD at our institution between January 2022 and June 2024. Patients were classified into three groups: PECS (n=32), DP (n=7), and no-PECS/no-DP (NPD) (n=279). Multivariate analysis was performed to identify predictors of PECS for clinical factors and values such as C-reactive protein (CRP), white blood cell (WBC) count, and body temperature. Based on significant predictors, we constructed a five-variable PECS-predictive scoring system (FPSS) for early post-procedure prediction of PECS. Results: Among 318 patients, the incidence of PECS and DP was 10.1% and 2.2%, respectively. DP cases demonstrated greater CRP elevation (p<0.001) and higher leukocytosis (p=0.011) compared with PECS, while PECS cases showed significantly higher WBC (p<0.001) and CRP (p<0.001) than the NPD group. Multivariate analysis identified five independent predictors of PECS: right colon (OR=3.54; p=0.004), female gender (OR=2.10; p=0.018), body temperature ≥37.6°C (OR=16.70; p8,000/µL on day 1 (OR=13.78; p24 mm (OR=3.03; p=0.003). The FPSS (range 0–9) achieved an AUC of 0.881, with high negative predictive value (97.4%). Conclusion: The characteristics of PECS were clarified in comparison with NPD and DP, and the newly developed FPSS demonstrated excellent diagnostic performance of PECS.

Introduction: Right-sided lesions are frequently missed during colonoscopy, and the diagnostic performance of image-enhanced endoscopy (IEE) modalities remains debated. This multicenter randomized controlled trial compared linked color imaging (LCI) with second-generation narrow-band imaging (2G-NBI) for adenoma detection and miss rates in the right colon. Methods: Patients undergoing colonoscopy at six centers in Japan between November 2020 and November 2023 were randomly assigned (1:1) to primary right-colon observation with LCI or 2G-NBI, followed by secondary white-light imaging (WLI). The primary outcome was adenoma detection rate (ADR) in the right-sided colon during primary IEE observation. Secondary outcomes included polyp detection rate (PDR) and miss rates of adenomas and polyps. Results: A total of 1,528 patients were analyzed (LCI, n = 776; 2G-NBI, n = 752). ADR did not significantly differ between the LCI group and the 2G-NBI group (26.7% vs. 23.4%, p = 0.14). PDR was also comparable (32.6% vs. 28.9%, p = 0.12). However, secondary WLI identified fewer additional polyps after LCI than after 2G-NBI (12.4% vs. 16.4%, p = 0.026). Per-lesion miss rates were significantly lower with LCI for both adenomas (19.9% vs. 31.4%) and polyps (21.5% vs. 31.9%) (both p < 0.001). Multivariable analyses confirmed the association between LCI and a reduced risk of missed lesions, with more pronounced associations observed in cases of poor bowel preparation, procedures by expert endoscopists, and observation times ≤70 s. Conclusion: Although ADR did not differ significantly between modalities, lower miss rates in the right-sided colon were observed with LCI. The Japan Registry of Clinical Trials (jRCT1012200007).

Background and Objectives: Bowel bubble formation during colonoscopy can impair mucosal visualization and reduce procedural efficiency. However, its clinical significance remains incompletely characterized. This study aimed to evaluate the prevalence of severe bowel bubbles in the proximal colon and their impact on colonoscopic quality in patients undergoing bowel preparation with oral sulfate solution (OSS), using either a same-day regimen (SAR) with 480 mL OSS or a split-day regimen (SPR) with 960 mL OSS. Methods: This retrospective study was conducted between October 2024 and December 2025 across two affiliated institutions. Patients who underwent colonoscopy with OSS-based bowel preparation were included. SAR was used for screening, symptomatic evaluation, and surveillance colonoscopy. SPR was applied exclusively to patients with a prior history of sodium picosulfate-related abdominal pain or inadequate bowel preparation with SAR. Sodium picosulfate was prescribed on the day before colonoscopy in the SAR group and a low-residual diet was administered in both the SAR and SPR groups. The prevalence of severe bubbles in the proximal colon was evaluated, and their impact on colonoscopic quality was examined. Results: A total of 176 SAR cases and 51 SPR cases were analyzed. The rate of severe bubbles in the proximal colon was identical between both regimens (17.6%). Compared with cases without severe bubbles, those with severe bubbles had significantly longer cecal insertion times (median [IQR]: 7.0 [5.0–10.0] vs. 9.0 [7.0–13.0] min, p = 0.018) and total procedure time (20.0 [16.0–25.0] vs. 24.0 [19.0–30.0] min, p = 0.024). Preparation-to-colonoscopy time was also longer in cases with severe bubbles (5.0 [4.0–5.5] vs. 5.0 [5.0–6.0] h, p = 0.041). Adenoma detection rates were 73.2% in cases without severe bubbles and 67.5% in those with severe bubbles (p = 0.571). Conclusions: Severe bowel bubble formation tended to be associated with longer cecal insertion and total procedure times, and was more frequently observed with a longer preparation-to-colonoscopy interval.

Endoscopic submucosal dissection (ESD) for colorectal lesions has become widely accepted but remains technically demanding, with perforation risk related to luminal distension and suboptimal visualization. Gel immersion ESD (GI-ESD) may offer mechanistic advantages over conventional CO2-insufflation ESD (C-ESD), including reduced colonic distension, improved visibility/depth perception, buoyancy-assisted dissection stability, and heat-sink protection. We hypothesized that these features would improve short-term safety and procedure stability. In this single-center retrospective study, 426 consecutive colorectal ESD cases (from January 2022 to December 2024) were analyzed. C-ESD was performed from January 2022 to March 2024; GI-ESD using Viscoclear (Otsuka Pharmaceutical Factory, Tokushima, Japan) from April to December 2024. After excluding non-epithelial lesions, 392 patients were included, including interrupted procedures. The primary outcome was adverse events (perforation, delayed bleeding). Secondary outcomes were en bloc and R0 resection rates, procedure time, and postoperative inflammatory response. Of 392 patients, 293 underwent C-ESD and 99 underwent GI-ESD were analyzed. En-bloc and R0 resection rates were comparable between GI-ESD and C-ESD (97.0% vs. 99.9%, P = 0.16, 90.6% vs. 91.4%, P = 0.35). The perforation rate was significantly lower in GI-ESD (0% vs. 4.1%, P = 0.04). Postoperative fever (≥ 37.6°C; 4.2% vs. 12.7%, P = 0.02) and median CRP elevation (0.33 mg/dl vs. 0.42 mg/dl, P < 0.01) were also significantly reduced in GI-ESD; however, incidence of post-endoscopic submucosal dissection electrocoagulation syndrome (PECS) was not significantly different between groups. GI-ESD achieved curative outcomes comparable to C-ESD while reducing perforation risk; PECS remained comparable between groups.

Background: This retrospective study aimed to verify the efficacy of endoscopic submucosal dissection (ESD) using a scissor‐type knife for early gastric cancer (EGC). Methods: The patients who underwent ESD for EGC between April 2014 and March 2022 were enrolled. The primary endpoint of this study was to assess the efficacy of a scissor‐type knife by comparing the self‐completion rate of trainees between gastric ESD performed using a scissor‐type knife (ESD‐SC) and nonscissor devices (ESD‐NS). Results: Of the 903 lesions, 485 and 418 underwent ESD‐SC and ESD‐NS, respectively. The self‐completion rate of trainees was significantly higher for ESD‐SC than for ESD‐NS (50.3 and 33.0%, respectively; p < 0.001). The procedure time was also significantly shorter for ESD‐SC (50.0 vs. 66.5 min, respectively; p < 0.001). Intraoperative perforation rate was not significantly different (0.6% for ESD‐SC and 1.4% for ESD‐NS, respectively). In multivariate analyses, tumor located in the lower third of the stomach (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.46–2.55, p < 0.001), tumor size ≤ 20 mm (OR 3.32, 95% CI 2.20–5.00, p < 0.001), and a scissor‐type knife (OR 2.22, 95% CI 1.67–2.94, p < 0.001) were factors related to the self‐completion rate of trainees for gastric ESD. Conclusions: A scissor‐type knife was associated with higher self‐completion rates and shorter procedure times among trainees. Further prospective studies are needed to validate its clinical utility in ESD training.

Introduction: Improvement of small intestinal lesions is essential for achieving favorable long-term outcomes in patients with Crohn’s disease (CD); however, evidence regarding the efficacy of biologics for small bowel involvement remains limited. Risankizumab (RZB), a selective interleukin-23 (IL-23) p19 inhibitor, has shown efficacy in large randomized trials; however, data on its effect on small intestinal inflammation are limited. This study aimed to evaluate the real-world effectiveness of RZB on small intestinal lesions using balloon-assisted enteroscopy. Methods: We conducted a retrospective study of patients with CD who received RZB between July 2023 and January 2025. Clinical activity was assessed using the Harvey-Bradshaw Index (HBI), and serum biomarkers (albumin, C-reactive protein, and hemoglobin) were measured longitudinally. Endoscopic activity was evaluated using the Simple Endoscopic Score for CD (SES-CD) before treatment and at 28 weeks after treatment; paired endoscopic assessment was available in 16 patients. Results: A total of 23 patients met the inclusion criteria. At baseline, 10 patients had clinically active disease (HBI ≥4), and 13 were in clinical remission (HBI ≤3). In the active group, HBI and C-reactive protein levels decreased after treatment, whereas hemoglobin and albumin concentrations increased during follow-up (HBI: p < 0.01; CRP: p < 0.05; hemoglobin: p < 0.05; albumin: p < 0.05). Among the 16 patients who underwent paired endoscopic evaluation, both total and ileal SES-CD scores decreased after 28 weeks of RZB therapy, demonstrating mucosal improvement in the terminal ileum (total SES-CD: p < 0.0001; ileal SES-CD: p = 0.0001). Notably, several patients who showed inadequate response to ustekinumab (UST) also exhibited endoscopic improvement after RZB treatment. Conclusions: RZB was effective in improving clinical and endoscopic disease activities, including terminal ileal lesions, even in patients who were previously refractory to UST. Given the prognostic importance of small bowel inflammation, these findings highlight the potential of selective IL-23p19 inhibition as a valuable therapeutic option for patients with small bowel-dominant CD.

Objectives: Sudden decrease of colonoscopy (CS) numbers can be related to the status of colorectal cancer (CRC). This study aimed to evaluate the statuses of CS and CRC according to big national disasters such as the Great East Japan Earthquake in 2011 and the COVID‐19 epidemic in 2020. Methods: We retrospectively used the JMDC database of commercially anonymized health insurance claims data including 4,601,921 patients ≥ 50 years old from January 2010 to December 2022 (without health checkups of CS and esophagogastroduodenoscopy [EGD]). The main outcome was a yearly analysis for 2010–2022 about (1) rate of CS, (2) rate of CRC and rate of CRC per CS compared to those of EGD and gastric cancer (GC), and (3) rate of surgery for CRC. Additionally, a monthly analysis for those rates was performed to examine the detailed effect of the earthquake and COVID‐19 infection. Results: The rates of CS and EGD in 2010/2011/2012 were 3.10%/3.41%/3.42% and 6.94%/6.96%/7.00% and those in 2019/2020/2021 were 5.20%/4.74%/5.37% and 7.47%/6.42%/6.84%, respectively. The rates of CS and EGD decreased not in 2011 (The earthquake) but in 2020 (COVID‐19). The rates of CRC and GC in 2019/2020/2021 were 0.199%/0.175%/0.195% and 0.110%/0.096%/0.099%, and both showed a decrease in 2020. Monthly analysis showed that the rate of CRC per CS had an increase in April and May in 2020 compared to that in March of 2020. The rate of surgery for CRC in 2019/2020/2021 was 0.087%/0.079%/0.087% with a deficiency in 2020. Conclusions: The rates of CS and CRC decreased in 2020 due to COVID‐19.