Randomised controlled, patient-blinded, multicentre, superiority trial to evaluate the efficacy of the line-attached sheath-type traction device for endoscopic submucosal dissection in patients with superficial gastric neoplasms.

INTRODUCTION: EndoTrac is a line-attached sheath-type traction device that enables us to control the direction and the force of traction during endoscopic submucosal dissection (ESD). The efficacy of EndoTrac for gastric ESD has not been fully verified. METHODS AND ANALYSIS: The G-Trac study is a multicentre (nine general hospitals and two university hospitals in Japan) collaborative trial assessing the efficacy of EndoTrac for gastric ESDs. Patients with superficial gastric neoplasms will be enrolled and randomly assigned to undergo either conventional ESD or EndoTrac ESD. Allocation will be stratified according to tumour location, operator experience and tumour diameter at an allocation rate of 1:1. The type of endoknife used will be confirmed before randomisation. The primary outcome, procedure time, will be compared between the groups in both intention-to-treat and per-protocol analyses using the Wilcoxon rank sum test. The efficacy-related, safety-related and device-related outcomes will be assessed in the secondary analysis. The planned sample size of the 142 patients in the two groups will enable us to detect a difference with a power of 80% by using the Wilcoxon rank sum test, assuming an effect size of 0.54, asymptotic relative efficiency of 0.864 and a two-sided type 1 error rate of 5%. ETHICS AND DISSEMINATION: This trial was approved by the certified review board of Kobe University (22 December 2022). The results from this trial will be disseminated through peer-review journals, presentations at national and international conferences, and data sharing with other researchers. TRIAL REGISTRATION NUMBER: jRCT1052220166.

Outcomes of endoscopic submucosal dissection for esophageal cancer with segmental absence of intestinal musculature.

BACKGROUND AND AIMS: Perforation during esophageal endoscopic submucosal dissection (ESD) typically results from electrical damage. However, there are cases in which perforation occurs because of segmental absence of intestinal musculature (SAIM) without iatrogenic muscular injury. We investigated the occurrence rate and clinical course of SAIM during esophageal ESD. METHODS: We conducted a retrospective review of esophageal ESDs performed between 2013 and 2019 at 10 centers in Japan. RESULTS: Five of 1708 (0.29%) patients received ESD for esophageal cancer and had SAIM. The median muscular defect size was 20 mm. All lesions were resected without discontinuation. After resection, 3 patients were closed with Endoloop. Four patients had mediastinal emphysema. All patients were managed conservatively. CONCLUSIONS: SAIM is a very rare condition that is usually only diagnosed during ESD. Physicians performing esophageal ESD should be aware of SAIM. When SAIM is detected, the ESD technique should be modified to prevent full-thickness perforation.

Assessment of predictive factors associated with the technical difficulty of endoscopic submucosal dissection for superficial esophageal squamous cell carcinoma: Japanese multicenter retrospective study.

OBJECTIVES: Endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma (ESCC) is performed for the treatment of lesions with varied backgrounds and factors. However, the predictive factors associated with the technical difficulty of ESD remain unknown in patients with varied lesions. Therefore, this study aimed to identify the predictive factors associated with the technical difficulty of ESD for ESCC using a retrospective cohort. METHODS: This multicenter, retrospective study was conducted in 10 hospitals in Japan. Consecutive patients who underwent esophageal ESD between January 2013 and December 2019 were enrolled. Lesions of subepithelial tumors, adenocarcinoma, and adenoma were excluded. Difficult lesions were defined as ESD requiring a long procedure time (≥120 min), perforation development, piecemeal resection, or discontinued ESD. In the present study, the clinical factors were assessed to identify the technical difficulty of ESD using univariate and multivariate analyses. RESULTS: Among 1708 lesions treated with esophageal ESD, eight subepithelial tumors, 44 adenocarcinomas, and two adenomas were excluded. Finally, 1505 patients with 1654 lesions were analyzed, and 217 patients with 217 lesions (13.1%) were classified as patients with difficult lesions. In multivariate analysis, the predictive factors associated with the technical difficulty of ESD were as follows: tumors with varices, tumors with diverticulum, antiplatelet use (discontinued), circumference of tumor (≥1/2), preoperative tumor size ≥30 mm, trainee, and nonhigh-volume center. CONCLUSION: This multicenter retrospective study identified the predictive factors associated with the technical difficulty of ESD for ESCC with varied backgrounds and factors.

Long-Term Outcomes of Endoscopic Submucosal Dissection for Early Remnant Gastric Cancer: A Retrospective Multicenter Study.

INTRODUCTION: Favorable long-term outcomes of endoscopic submucosal dissection (ESD) for early remnant gastric cancer (ERGC) have been reported in single-center studies from advanced institutions. However, no studies have examined the long-term outcomes using a multicenter database. This study aimed to investigate the long-term outcomes of the aforementioned approach using a large multicenter database. METHODS: This retrospective multicenter cohort study included 242 cases with 256 lesions that underwent ESD for ERGC between April 2009 and March 2019 across 12 centers. We investigated the long-term outcomes of these patients with the Kaplan-Meier method, and the relationship between curability, additional treatment, or hospital category, and the survival time was evaluated using the log-rank test. RESULTS: During the median follow-up period of 48.4 months, the 5-year overall survival rate was 81.3%, and the 5-year gastric cancer-specific survival rate was 98.1%. The survival time of patients of endoscopic curability (eCura) C-2 without additional surgery was significantly shorter than the corresponding of patients of eCura A/B/C-1 and eCura C-2 with additional surgery. There was no significant difference in either overall survival or gastric cancer-specific survival rate between the high-volume and non-high-volume hospitals. CONCLUSION: The gastric cancer-specific survival of ESD for ERGC using a multicenter database was favorable. ESD for ERGC is widely applicable regardless of the hospital case volume. Management in accordance with the latest guidelines will lead to long-term survival.

Safety and efficacy of endoscopic submucosal dissection for superficial esophageal cancer with esophageal varices.

BACKGROUND: Heavy drinking is associated with esophageal cancer and esophageal varices. However, there are limited reports of endoscopic resection for esophageal cancer with esophageal varices. In this multicenter study, we clarified the safety and efficacy of endoscopic submucosal dissection for superficial esophageal cancer with esophageal varices. METHODS: In this multicenter, retrospective, observational study, patients underwent esophageal endoscopic submucosal dissection at 10 referral centers in Japan from January 2013 to December 2019. We analyzed characteristics including backgrounds and varices, treatment outcomes, and adverse events in cases with esophageal varices. RESULTS: A total of 1708 patients were evaluated, 27 (1.6%) of whom had esophageal varices. In patients with esophageal varices, the en bloc resection rate and R0 resection rate were 100% and 77.8%, respectively. Patients with esophageal varices had longer procedure times than patients without esophageal varices (p = 0.015). There was no significant difference in adverse events. There was no significant difference in procedure time and number of adverse events between patients who underwent pretreatment and those who did not. There was no significant difference in these outcomes for patients with lesions on varices compared to those without. Child-Pugh classification and location of the lesions also did not affect these outcomes. CONCLUSIONS: Esophageal cancer with esophageal varices could be treated endoscopically safely and effectively.

Characteristics of Gastric Stasis due to Deformation after Endoscopic Submucosal Dissection in the Lower Part of the Stomach.

INTRODUCTION: Gastric stasis due to deformation occurs after endoscopic submucosal dissection in the lower part of the stomach. Endoscopic balloon dilation can improve gastric stasis due to stenosis; however, endoscopic balloon dilation cannot improve gastric stasis due to deformation. Furthermore, the characteristics of gastric stasis due to deformation are unknown. This study aimed to evaluate the characteristics of gastric stasis due to deformation after endoscopic submucosal dissection in the lower part of the stomach, focusing on the differences between stenosis and deformation. METHODS: We retrospectively reviewed 41 patients with gastric stasis after endoscopic submucosal dissection in the lower part of the stomach. We evaluated the characteristics of cases with gastric stasis due to deformation, such as the risk factors of deformation and the rate of deformation in each group with risk factors. RESULTS: Deformation was observed in 12% (5/41) of the patients with gastric stasis. All cases of deformation had a circumferential extent of the mucosal defect greater than 3/4. The number of cases with pyloric dissection was significantly lower in the deformation group than in the non-deformation group (0% vs. 72%; p = 0.004). The deformation group also had a significantly higher number of cases with angular dissection than the non-deformation group (100% vs. 17%; p < 0.001). Moreover, the deformation cases had a significantly larger specimen diameter (p < 0.001). Deformation was observed only in cases with angular and non-pyloric dissections. Deformation was not observed in cases with angular and pyloric dissections. CONCLUSIONS: All cases of gastric stasis due to deformation had a circumferential extent of the mucosal defect greater than 3/4. Deformation was also likely to occur in cases with a larger dissection that exceeded the angular region without pyloric dissection.

Clinicopathological Features and the Prevalence of Oxyntic Gland Neoplasm: A Single-center Retrospective Study.

Objective We explored the clinicopathological characteristics and disease frequency of oxyntic gland neoplasms (OGNs). Methods We retrospectively evaluated the data of patients pathologically diagnosed with OGN at an internal medicine clinic. Patients A total of 13,240 upper gastrointestinal endoscopies were performed on 7,488 patients between December 1, 2017, and March 31, 2021. Results We identified 27 patients with 30 histopathologically confirmed OGNs, yielding a disease frequency of 0.36% (27/7,488). Furthermore, multiple simultaneous lesions were found in 3 of 27 patients (11%). One (3.3%) of the 30 lesions was present in the antrum, whereas the remaining lesions occurred in the body of the stomach. Nine (33%) of the 27 patients had no history of Helicobacter pylori infection, whereas the remaining 18 (67%) were either currently or had been previously infected. Nevertheless, 27/30 lesions (90%) still occurred in non-atrophied regions. After endoscopic treatment, a histopathological examination of the resected specimens revealed submucosal infiltration in 8 (44%) of the 18 lesions; however, none of the lesions showed submucosal desmoplasia. For all patients with submucosal involvement, only observation was performed. There were no recurrent lesions found on follow-up. Conclusion The period prevalence of OGN was 0.36%, which is much higher than previously reported. The discovery of a small submucosal appearing lesion with a faded yellow or white color and dilated microvasculature, especially in a non-atrophic area of the stomach, should raise suspicion for an OGN, which can be endoscopically managed.

Efficacy of lidocaine injection method for esophageal endoscopic submucosal dissection: single-center, double-blind, randomized controlled trial.

BACKGROUND: Intraoperative body movements are one of the causes of difficulty in performing esophageal endoscopic submucosal dissection (ESD) under conscious sedation. The use of local anesthetics as local injection materials during ESD may overcome this difficulty. We clinically evaluated the lidocaine injection method (LIM) in the submucosa during esophageal ESD. METHODS: This was a single-center, prospective, double-blind, randomized trial. Patients who underwent esophageal ESD under conscious sedation from June 2018 to May 2021 were included in this study. In the LIM group, lidocaine was used for submucosal injection during ESD; in the control group, ESD was performed without lidocaine. The primary outcome was the presence of body movements. RESULTS: Fifty patients were enrolled and randomized in a 1:1 ratio in two groups. The incidence of body movements was significantly lower in the LIM group (12% [3/25]) than in the control group (48% [12/25]; P = 0.01). The median additional dose of midazolam was 2 mg (interquartile range [IQR]: 0.5-4 mg) in the LIM group and 4 mg (IQR: 3-6 mg) in the control group, which was significantly lower in the LIM group (P < 0.01). The median visual analog scale score for endoscopist satisfaction was 7 (IQR: 5-8) in the LIM group and 5 (IQR: 4-6.5) in the control group, which was significantly higher in the LIM group. CONCLUSIONS: LIM during esophageal ESD reduced body movements while decreasing the level of sedation. Therefore, LIM during esophageal ESD is an option for maintaining good sedation (UMIN000032804).

Predicting Inadequate Bowel Preparation When Using Sodium Picosulfate plus Magnesium Citrate for Colonoscopy: Development and Validation of a Prediction Score.

INTRODUCTION: Sodium picosulfate plus magnesium citrate is a bowel preparation agent with high patient acceptability. However, it is unclear which patients are more likely to have inadequate bowel preparation when using this agent. This study aimed to identify the risk factors for inadequate bowel preparation when using sodium picosulfate plus magnesium citrate for colonoscopy and to develop a scoring model to predict which patients will have inadequate bowel preparation. METHODS: A total of 350 Japanese patients were enrolled from June 2021 to April 2022. Data on patient background, details of colonoscopy, and satisfaction assessment questionnaire results were prospectively collected. The scoring model for inadequate bowel preparation was developed based on multiple logistic regression analyses, and its performance was internally validated using bootstrapping. RESULTS: Adequate bowel preparation was obtained in 295 patients (84.3%); 335 (95.7%) were able to ingest the drug without difficulty. The scoring model consisted of five independent risk factors and points of risk scores were assigned to each one as follows: American Society of Anesthesiologists physical status III (1 point), diabetes comorbidities (5 points), use of laxatives (4 points), no defecation once in a day (2 points), and drug use for mental disorder (6 points). The C-statistics of the scoring system for inadequate bowel preparation was 0.75. DISCUSSION: We identified five risk factors for inadequate bowel preparation when using sodium picosulfate plus magnesium citrate regimen and developed a scoring model for inadequate bowel preparation with satisfactory discrimination and calibration.

Efficacy of specimen pasting after cold snare polypectomy for pathological evaluation of horizontal margins.

Background and study aims Several studies have reported that pathological horizontal margin evaluation cannot be diagnosed in cold snare polypectomy (CSP) specimens. We conducted a prospective randomized controlled trial to determine the efficacy of pasting CSP specimens on paper for pathological horizontal margins. Patients and methods This was a single-center, prospective study conducted at Osaka Saiseikai Nakatsu Hospital. In this study, the indications for CSP were adenomas ≤ 10 mm. Colorectal polyps resected by CSP were randomized to the pasting and non-pasting groups after exclusion of fragmented specimens, and the extended CSP specimens pasted on paper were formalin-fixed in the pasting group. The primary endpoint was rate of unclear horizontal margins after CSP. Results A total of 216 CSP specimens were analyzed. The rate of unclear horizontal margins was significantly lower in the pasting group than in the non-pasting group (15.1 % vs 33.6 %, P  = 0.002). CSP specimen pasting significantly reduced the rate of unclear horizontal margins. On multivariate analysis, non-pasting group (odds ratio [OR], 2.69; 95 % confidence interval [CI], 1.38-5.41; P  = 0.003) and right colon (OR, 1.98; 95 %CI, 1.01-4.01; P  = 0.047) were independent risk factors for unclear horizontal margins in CSP specimens. Conclusions Pasting the extended specimen is important for accurate pathological examination after CSP.

Feasibility and safety of endoscopic submucosal dissection for lesions in proximity to a colonic diverticulum.

BACKGROUND/AIMS: Endoscopic submucosal dissection (ESD) for diverticulum-associated colorectal lesions is generally contraindicated because of the high risk of perforation. Several studies on patients with such lesions treated with ESD have been reported recently. However, the feasibility and safety of ESD for lesions in proximity to a colonic diverticulum (D-ESD) have not been fully clarified. The aim of this study was to evaluate the feasibility and safety of D-ESD. METHODS: D-ESD was defined as ESD for lesions within approximately 3 mm of a diverticulum. Twenty-six consecutive patients who underwent D-ESD were included. Two strategic approaches were used depending on whether submucosal dissection of the diverticulum-related part was required (strategy B) or not (strategy A). Treatment outcomes and adverse events associated with each strategy were analyzed. RESULTS: The en bloc resection rate was 96.2%. The rates of R0 and curative resection in strategies A and B were 80.8%, 73.1%, 84.6%, and 70.6%, respectively. Two cases of intraoperative perforation and one case of delayed perforation occurred. The delayed perforation case required emergency surgery, but the other cases were managed conservatively. CONCLUSION: D-ESD may be a feasible treatment option. However, it should be performed in a high-volume center by expert hands because it requires highly skilled endoscopic techniques.

Clinical Impact of Different Reconstruction Methods on Remnant Gastric Cancer at the Anastomotic Site after Distal Gastrectomy.

BACKGROUND/AIMS: The anastomotic site after distal gastrectomy is the area most affected by duodenogastric reflux. Different reconstruction methods may affect the lesion characteristics and treatment outcomes of remnant gastric cancers at the anastomotic site. We retrospectively investigated the clinicopathologic and endoscopic submucosal dissection outcomes of remnant gastric cancers at the anastomotic site. METHODS: We recruited 34 consecutive patients who underwent endoscopic submucosal dissection for remnant gastric cancer at the anastomotic site after distal gastrectomy. Clinicopathology and treatment outcomes were compared between the Billroth II and non-Billroth II groups. RESULTS: The tumor size in the Billroth II group was significantly larger than that in the non-Billroth II group (22 vs. 19 mm; p=0.048). More severe gastritis was detected endoscopically in the Billroth II group (2 vs. 1.33; p=0.0075). Moreover, operation time was longer (238 vs. 121 min; p=0.004) and the frequency of bleeding episodes was higher (7.5 vs. 3.1; p=0.014) in the Billroth II group. CONCLUSION: Compared to remnant gastric cancers in non-Billroth II patients, those in the Billroth II group had larger lesions with a background of severe remnant gastritis. Endoscopic submucosal dissection for remnant gastric cancers in Billroth II patients involved longer operative times and more frequent bleeding episodes than that in patients without Billroth II.

The risk scoring system for assessing the technical difficulty of endoscopic submucosal dissection in cases of remnant gastric cancer after distal gastrectomy.

BACKGROUND: Endoscopic submucosal dissection (ESD) for remnant gastric cancer (RGC) after distal gastrectomy (DG) is considered technically challenging due to the narrow working space, and severe fibrosis and staples from the previous surgery. Technical difficulties of ESD for RGC after DG have not been thoroughly investigated. This study aimed to develop and validate a risk-scoring system for assessing the technical difficulty of ESD for RGC after DG in a large multicenter cohort. METHODS: We investigated patients who underwent ESD for RGC after DG in 10 institutions between April 2008 and March 2018. A difficult case was defined as ESD lasting ≥ 120 min, involving piecemeal resection, or the occurrence of perforation during the procedure. A risk-scoring system for the technical difficulty of the procedure was developed based on multiple logistic regression analyses, and its performance was internally validated using bootstrapping. RESULTS: A total of 197 consecutive patients with 201 lesions were analyzed. There were 90 and 111 difficult and non-difficult cases, respectively. The scoring model consisted of four independent risk factors and points of risk scores were assigned for each as follows: tumor size > 20 mm: 2 points; anastomosis site: 2 points; suture line: 1 point; and non-expert endoscopist: 2 points. The C-statistics of the scoring system for technical difficulty was 0.72. CONCLUSIONS: We developed a validated risk-scoring model for predicting the technical difficulty of ESD for RGC after DG that can contribute to its safer and more reliable performance.

Timing of pyloric stenosis and effectiveness of endoscopic balloon dilation after pyloric endoscopic submucosal dissection.

BACKGROUND AND AIM: There have been studies on risk factors for stenosis after pyloric endoscopic submucosal dissection (ESD). However, the most appropriate strategies for the management of cases with these risk factors have not been established. This study aimed to investigate post-ESD management by evaluating the timing of stenosis and the effectiveness of endoscopic balloon dilation (EBD) after pyloric ESD. METHODS: We retrospectively reviewed cases of pyloric ESD. We first reassessed risk factors for stenosis in multivariate analysis and receiver operating characteristic curve and defined patients with the identified risk factors as the risk group. The primary outcome was the timing of stenosis in the risk group assessed by the Kaplan-Meier method. RESULTS: We reviewed 159 cases with pyloric ESD and observed pyloric stenosis in 25 cases. Cases with circumferential mucosal defect ≥ 76% were identified as the risk group. The stenosis-free probability in the risk group was 97% (95% confidence interval [CI]: 79-100%), 94% (95% CI: 76-98%), and 85% (95% CI: 66-93%) on days 7, 14, and 21, respectively. It decreased every week thereafter and did not significantly change after day 56. Twenty-three stenosis cases, except for conservative improvement, including six whole circumferential pyloric ESD cases, were improved by EBD without complications. CONCLUSIONS: Post-ESD stenosis often developed from the third to the eighth week. In all pyloric ESD cases, including whole circumferential pyloric ESD cases, pyloric stenosis was improved following EBD without complications.

A rare case of pyogenic granuloma of the jejunum causing gastrointestinal bleeding.

Pyogenic granulomas (PG) are lobular capillary hemangiomas mostly found in the mucous membranes of the skin and oral cavity, and rarely occur in the gastrointestinal tract. Here we describe a case of an 84-year-old patient with alcoholic cirrhosis who presented with persistent melena and progressive anemia. Endoscopy showed esophageal varices and he underwent endoscopic variceal ligation (EVL) with transient resolution of anemia. However, due to worsening anemia, he underwent capsule endoscopy that revealed a bleeding tumor in the small intestine. We performed double-balloon endoscopy and found a 7-mm polyp with a white coat located in the jejunum and resected it at a later date. Histological characteristics led to the diagnosis of PG, and the patient's melena and anemia subsequently improved.

Feasibility of the lidocaine injection method during esophageal endoscopic submucosal dissection.

BACKGROUND AND AIM: Esophageal endoscopic submucosal dissection (ESD) is often technically difficult due to intraoperative body movements. The level of sedation can be increased to suppress body movements, but this may not be successful in all cases. Using local analgesics for submucosal injection during ESD may aid in conscious sedation. This study evaluated the feasibility of the lidocaine injection method (LIM) during esophageal ESD. METHODS: Twenty-nine patients with superficial esophageal cancer were enrolled in this study at Osaka Saiseikai Nakatsu Hospital, and 1% lidocaine + 0.4% hyaluronate sodium was injected into the submucosa underneath the lesion during esophageal ESD. The main outcome was body movements that disturbed the procedure. RESULTS: Most patients were male (90%), with a median age of 70 years (interquartile range [IQR]: 66-75 years old), and the median lesion size was 17 mm (IQR: 12-21 mm). The median injection volume of lidocaine was 70 mg (IQR: 55-79 mg). All lesions were successfully removed en bloc. In all cases, there were no body movements that disturbed the procedure. Regarding adverse events of sedation, five patients (17%) had hypotension, four patients (14%) had bradycardia, and seven patients (24%) had hypoxemia during ESD. Convulsions or arrhythmia as adverse events associated with lidocaine were not observed. CONCLUSIONS: Esophageal ESD with LIM did not cause body movements that disturbed the procedure. LIM may help create a stable conscious sedation method for esophageal ESD.

Endoscopic submucosal dissection for early gastric cancer on the lesser curvature in upper third of the stomach is a risk factor for postoperative delayed gastric emptying.

BACKGROUND: Advances in Endoscopic submucosal dissection (ESD) technology have established ESD for early gastric cancer as a safe and stable technique. However, ESD may induce delayed gastric emptying and the cause of food residue retention in the stomach after ESD is not clear. This study aimed to clarify risk factors for delayed gastric emptying with food retention after gastric ESD. METHODS: We retrospectively examined for food residue in the stomach 1 week after ESD was performed for early gastric carcinoma at Osaka Saiseikai Nakatsu Hospital from February 2008 to November 2016. RESULTS: Food residue was observed in 68 (6.1%) of 1114 patients who underwent gastric ESD. The percentage of lesions located on the lesser curvature of the upper third of the stomach was 45.6% (31/68) in the food residue group and 3.5% (37/1046) in the non-food residue group, which was significantly different (P < 0.01). Multivariate logistic regression analysis revealed that lesions on the lesser curvature of the upper third of the stomach (Odds ratio [OR] 23.31, 95% confidence interval [CI] 12.60-43.61, P < 0.01), post-ESD bleeding (OR 4.25, 95%CI 1.67-9.80, P < 0.01), submucosal invasion (OR 2.80, 95%CI 1.34-5.63, P < 0.01), and age over 80 years (OR 2.34, 95%CI 1.28-4.22, P < 0.01) were independent risk factors for food retention after gastric ESD. Of the 68 patients, 3 had food residue in the stomach on endoscopic examination for follow-up observation after the ESD ulcer had healed. CONCLUSIONS: Delayed gastric emptying with food retention after gastric ESD was associated with lesions located in the lesser curvature of the upper stomach, submucosal invasion of the lesion, age older than 80 years, and post-ESD bleeding, though it was temporary in most cases.

Clinical outcomes of deep invasive submucosal colorectal cancer after ESD.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) is a reliable method that can replace surgery under certain conditions. However, limited information is available on the clinical course of T1b colorectal cancer (CRC) after ESD. The aim of the study was to clarify the feasibility of ESD for T1b CRC. PATIENTS AND METHODS: Three hundred and two patients with 312 T1 CRC were identified in this retrospective cohort study. All patients were treated with ESD, other endoscopic treatments, or surgery. In this study, we (I) investigated the en bloc resection rate of ESD and (II) compared the overall survival (OS) rate for patients who underwent ESD with additional surgery (Group A) and surgery without upfront endoscopic resection (Group B) for T1b CRC. RESULTS: No significant differences were observed in the en bloc resection rates between T1b and T1a CRC (100 vs. 98.7%), but the en bloc R0 resection rate was significantly lower in T1b CRC than in T1a CRC (64.7 vs. 97.4%). Regarding complications, perforations occurred in 2.9% of patients with T1b CRC, which was not significantly different from the rate of 5.3% in patients with T1a CRC. No significant differences were observed in the OS or recurrence-free survival (RFS) curves between Groups A and B (OS rates at 5 years: 92.3 vs. 88.9%, RFS rates at 5 years: 81.4 vs. 85.3%). Similarly, the 5-year disease-specific survival (DSS) rate of Group A was identical to that of Group B (both 100%). CONCLUSIONS: ESD for T1b CRC before surgery is a possible strategy because of the low rate of complications and favorable long-term outcomes.