Risk factors for positive resection margins after endoscopic resection for gastrointestinal neuroendocrine tumors.

BACKGROUND: In recent years, the incidence of gastrointestinal neuroendocrine tumors (GI-NETs) has remarkably increased due to the widespread use of screening gastrointestinal endoscopy. Currently, the most common treatments are surgery and endoscopic resection. Compared to surgery, endoscopic resection possesses a higher risk of resection margin residues for the treatment of GI-NETs. METHODS: A total of 315 patients who underwent surgery or endoscopic resection for GI-NETs were included. We analyzed their resection modality (surgery, ESD, EMR), margin status, Preoperative marking and Prognosis. RESULTS: Among 315 patients included, 175 cases underwent endoscopic resection and 140 cases underwent surgical treatment. A total of 43 (43/175, 24.57%) and 10 (10/140, 7.14%) patients exhibited positive resection margins after endoscopic resection and surgery, respectively. Multivariate regression analysis suggested that no preoperative marking and endoscopic treatment methods were risk factors for resection margin residues. Among the patients with positive margin residues after endoscopic resection, 5 patients underwent the radical surgical resection and 1 patient underwent additional ESD resection. The remaining 37 patients had no recurrence during a median follow-up of 36 months. CONCLUSIONS: Compared with surgery, endoscopic therapy has a higher margin residual rate. During endoscopic resection, preoperative marking may reduce the rate of lateral margin residues, and endoscopic submucosal dissection may be preferred than endoscopic mucosal resection. Periodical follow-up may be an alternative method for patients with positive margin residues after endoscopic resection.

Efficacy and safety of precutting endoscopic mucosal resection versus endoscopic submucosal dissection for non-ampullary superficial duodenal lesions.

BACKGROUND: Endoscopic treatments for non-ampullary superficial duodenal lesions (NASDLs) are yet to be standardized. Endoscopic submucosal dissection (ESD) for NASDLs demands advanced techniques and a long procedure time to prevent perforation and bleeding. Precutting endoscopic mucosal resection (EMR) is a technical modification of ESD that overcomes the limitations of ESD. This study aimed to compare the efficacy and safety of precutting EMR versus ESD for NASDLs. METHODS: We conducted a retrospective analysis of patients with NASDLs treated with either precutting EMR or ESD from January 2015 to March 2023. RESULTS: A total of 90 patients with NASDLs were analyzed, with 44 patients in the precutting EMR group and 46 patients in the ESD group. The endoscopic procedure achieved satisfactory outcomes in both groups, with en block resection rate of 100.0 %. The R0 resection rates in the precutting EMR and ESD groups were 95.5 % and 93.5 %, respectively. No delayed perforation occurred postoperatively in either group. There were no significant differences between the two groups in age, gender, lesion location, layer of lesion origin, macroscopic type, and lesion size. The procedure time was significantly shorter in the precutting EMR group than in the ESD group (22.9 ± 7.1 min vs 36.0 ± 10.6 min, p<0.001). The intraoperative perforation rate was significantly lower in the precutting EMR group compared to ESD group (4.5% vs 19.6 %, p = 0.030). CONCLUSIONS: Precutting EMR is comparable to ESD for NASDLs, demonstrating a lower intraoperative perforation rate and shorter procedure time compared to ESD.

Normal Ileal Mucus Is Inadequate for Epithelial Protection in Ileal Pouch Mucosa.

BACKGROUND: Clinical, nonspecific pouchitis is common after restorative proctocolectomy for ulcerative colitis, but its cause is unknown. A possible lack of protection for the ileal mucosa in its role as a reservoir for colonic-type bacteria may be the missing piece in defining the causes of pouchitis. OBJECTIVE: The study aimed to review the causes of pouchitis and introduce the hypothesis that inadequate mucus protection in the pouch, combined with a predisposition to abnormal inflammation, is the most common cause of nonspecific pouchitis. DATA SOURCES: Review of PubMed and MEDLINE for articles discussing pouchitis and intestinal mucus. STUDY SELECTION: Studies published from 1960 to 2023. The main search terms were "pouchitis," and "intestinal mucus," whereas Boolean operators were used with multiple other terms to refine the search. Duplicates and case reports were excluded. MAIN OUTCOME MEASURES: Current theories about the cause of pouchitis, descriptions of the role of mucus in the physiology of intestinal protection, and evidence of the effects of lack of mucus on mucosal inflammation. RESULTS: The crossreference of "intestinal mucus" with "pouchitis" produced 9 references, none of which discussed the role of mucus in the development of pouchitis. Crossing "intestinal mucus" with "pouch" resulted in 32 articles, combining "pouchitis" with "barrier function" yielded 37 articles, and "pouchitis" with "permeability" yielded only 8 articles. No article discussed the mucus coat as a barrier to bacterial invasion of the epithelium or mentioned inadequate mucus as a factor in pouchitis. However, an ileal pouch produces a colonic environment in the small bowel, and the ileum lacks the mucus protection needed for this sort of environment. This predisposes pouch mucosa to bacterial invasion and chronic microscopic inflammation that may promote clinical pouchitis in patients prone to an autoimmune response. LIMITATIONS: No prior studies address inadequate mucus protection and the origin of proctitis. There is no objective way of measuring the autoimmune tendency in patients with ulcerative colitis. CONCLUSIONS: Studies of intestinal mucus in the ileal pouch and its association with pouchitis are warranted.

Risk factors of unintentional piecemeal resection in endoscopic mucosal resection for colorectal polyps ≥ 10 mm.

This study aimed to investigate the lesion and endoscopist factors associated with unintentional endoscopic piecemeal mucosal resection (uniEPMR) of colorectal lesions ≥ 10 mm. uniEPMR was defined from the medical record as anything other than a preoperatively planned EPMR. Factors leading to uniEPMR were identified by retrospective univariate and multivariate analyses of lesions ≥ 10 mm (adenoma including sessile serrated lesion and carcinoma) that were treated with endoscopic mucosal resection (EMR) at three hospitals. Additionally, a questionnaire survey was conducted to determine the number of cases treated by each endoscopist. A learning curve (LC) was created for each lesion size based on the number of experienced cases and the percentage of uniEPMR. Of 2557 lesions, 327 lesions underwent uniEPMR. The recurrence rate of uniEPMR was 2.8%. Multivariate analysis showed that lesion diameter ≥ 30 mm (odds ratio 11.83, 95% confidence interval 6.80-20.60, p < 0.0001) was the most associated risk factor leading to uniEPMR. In the LC analysis, the proportion of uniEPMR decreased for lesion sizes of 10-19 mm until 160 cases. The proportion of uniEPMR decreased with the number of experienced cases in the 20-29 mm range, while there was no correlation between the number of experienced cases and the proportion of uniEPMR ≥ 30 mm. These results suggest that 160 cases seem to be the minimum number of cases needed to be proficient in en bloc EMR. Additionally, while lesion sizes of 10-29 mm are considered suitable for EMR, lesion sizes ≥ 30 mm are not applicable for en bloc EMR from the perspective of both lesion and endoscopist factors.

Prevalence and clinical significance of the muscle retracting sign during endoscopic submucosal dissection of large macronodular colorectal lesions (with videos).

BACKGROUND AND AIMS: The muscle retracting sign (MRS) can be present during endoscopic submucosal dissection (ESD) of macronodular colorectal lesions. The prevalence of MRS and its pathologic and clinical implications is unclear. This study evaluated the effect of MRS on the technical and clinical outcomes of ESD. METHODS: All patients referred for ESD of protruding lesions or granular mixed lesions with >10 mm macronodule granular mixed laterally spreading tumors (LST-GMs) in 2 academic centers from January 2017 to October 2022 were prospectively included. Size of the macronodule was analyzed retrospectively. The primary outcome was the curative resection rate according to MRS status. Secondary outcomes were R0 resection, perforation, secondary surgery rate, and risk factors for MRS. RESULTS: Of 694 lesions, 84 (12%) had MRS (MRS+). The curative resection rate was decreased by MRS (MRS+ 41.6% vs lesions without MRS [MRS-] 81.3%), whereas the perforation (MRS+ 22.6% vs MRS- 9.2%), submucosal cancer (MRS+ 34.9% vs MRS- 9.2%), and surgery (MRS+ 45.2% vs MRS- 6%) rates were increased. The R0 resection rate of MRS+ colonic lesions was lower than that of rectal lesions (53% vs 74.3%). In multivariate analysis, protruding lesions (odds ratio, 2.47; 95% confidence interval, 1.27-4.80) and macronodules >4 cm (odds ratio, 4.24; 95% confidence interval, 2.23-8.05) were risk factors for MRS. CONCLUSIONS: MRS reduces oncologic outcomes and increases the perforation rate. Consequently, procedures in the colon should be stopped if MRS is detected, and those in the rectum should be continued due to the morbidity of alternative therapy.

Hybrid endoscopic submucosal dissection as a salvage option for difficult colorectal conventional endoscopic submucosal dissection.

BACKGROUND: When total submucosal dissection is difficult to achieve during conventional colorectal endoscopic submucosal dissection (C-ESD), the lesion can be resected by final snaring through salvage hybrid ESD (SH-ESD). This study aimed to examine the outcomes of SH-ESD and identify its indications that could achieve en bloc resection. METHODS: We recruited 1039 consecutive patients with colorectal lesions that underwent ESD at Hiroshima University Hospital between January 2015 and December 2020. C-ESD was attempted thoroughly in 924 lesions (C-ESD group, including 9 lesions in which ESD was discontinued), and SH-ESD was performed owing to some difficulties in 115 lesions (SH-ESD group). Risk factors for incomplete resection by SH-ESD and ESD discontinuation were evaluated using multivariate analysis. The outcomes were compared between cases with remaining undissected submucosa of < 20 mm in diameter in the SH-ESD and C-ESD groups, using propensity score matching. RESULTS: Multivariate analysis revealed that a procedure time > 80 min and remaining undissected submucosa ≥ 20 mm in diameter were significant risk factors for incomplete resection after SH-ESD and ESD discontinuation. By propensity score matching analysis, procedure time was significantly shorter in the SH-ESD group with remaining undissected submucosa < 20 mm in diameter than in the C-ESD group (71 min vs. 90 min, p = 0.0053), although no significant difference was found in the en bloc resection rate (94% vs. 87%, p = 0.0914). CONCLUSION: SH-ESD can be an alternative surgical method when conventional ESD is difficult to continue in cases in which the remaining undissected submucosa is < 20 mm in diameter.

Underwater clip closure method for mucosal defects after duodenal endoscopic submucosal dissection (with video).

Conventional clip closure of mucosal defects after duodenal endoscopic submucosal dissection decreases the incidence of delayed adverse events, but may result in incomplete closure, depending on size or location. This study aimed to assess the effectiveness of the underwater clip closure method for complete duodenal defect closure without the difficulties associated with conventional closure methods. We investigated 19 patients with 20 lesions who underwent endoscopic submucosal dissection of the duodenum and subsequent mucosal defect closure in underwater conditions at our facility between February 2021 and January 2022. The success rate of the underwater clip closure method was defined as the complete endoscopic closure of the mucosal defect; a success rate of 100% was achieved. The median resected specimen size was 34.3 mm, the median procedure time for mucosal defect closure was 14 min, and the median number of clips used per patient was 12. No delayed adverse events were observed. The underwater clip closure method is a feasible option for complete closure of mucosal defects, regardless of the size or location of a duodenal endoscopic submucosal dissection.

Superior predictive value of transmural over endoscopic severity for colectomy risk in ulcerative colitis: a multicentre prospective cohort study.

BACKGROUND AND AIMS: Endoscopic activity is associated with an increased risk of surgery in patients with ulcerative colitis [UC]. Transmural activity, as defined by Milan Ultrasound Criteria [MUC] > 6.2, reliably detects endoscopic activity in patients with UC. The present study aimed to assess in UC patients whether transmural severity is a better predictor of colectomy as compared to endoscopy. METHODS: Consecutive adult UC patients were recruited in two IBD Referral Centres and underwent colonoscopy and intestinal ultrasound in a blinded fashion. The need for colectomy was assessed at follow-up. Univariable and multivariable logistic and Cox regression analyses were performed. Receiver operating characteristic [ROC] analysis was used to compare MUC baseline values and Mayo Endoscopic Scores [MES] in predicting colectomy risk. RESULTS: Overall, 141 patients were enrolled, and 13 underwent colectomy in the follow-up period. Both MES (hazard ratio [HR]: 3.15, 95% confidence interval [CI]: 1.18-8.37, p = 0.02) and MUC [HR: 1.48, 95% CI: 1.19-1.76, p < 0.001] were associated with colectomy risk, but only MUC was independently associated with this event on multivariable analysis [HR: 1.46, 95% CI: 1.06-2.02, p = 0.02]. MUC was the only independent variable associated with colectomy risk in patients with clinically active disease (odds ratio [OR]: 1.53 [1.03-2.27], p = 0.03). MUC demonstrated higher accuracy than MES (area under ROC curve [AUROC] 0.83, 95% CI: 0.75-0.92 vs 0.71, 95% CI: 0.62-0.80) and better performance for predicting colectomy [p = 0.02]. The optimal MUC score cut-off value for predicting colectomy, as assessed by the Youden index, was 7.7. CONCLUSIONS: A superior predictive value was found for transmural vs endoscopic severity for colectomy risk in UC patients.

Curative Effect Analysis of Endoscopic Submucosal Dissection in Giant Laterally Spreading Rectal Tumors.

GOAL: The objective of this study was to investigate the clinical efficacy of endoscopic submucosal dissection (ESD) in the treatment of giant lateral developing rectal-type tumors (laterally spreading tumors, LSTs). BACKGROUND: There are no specialized studies on the efficacy of ESD in the treatment of LSTs measuring >5 cm in diameter, surgery was often used in the past, but it has the disadvantages of large trauma, many complications, and high cost. METHODS: The data of 185 patients with rectal LSTs who had undergone ESD in the digestive endoscopy center of our hospital from January 2012 to June 2020 were retrospectively analyzed. Based on the size of the lesions, the patients were divided into 2 groups: diameter ≤5 cm (110 cases) and diameter >5 cm (75 cases), and we summarized and analyzed the en bloc resection rate, curative resection rate, procedure time, muscle injury, bleeding, perforation, postoperative stricture, and recurrence. RESULTS: There was no difference in the en bloc resection rate and R0 resection rate between the 2 groups ( P =0.531). Moreover, there was no difference in the incidence of delayed perforation, postoperative stenosis, and recurrence, but the incidence of delayed bleeding was significantly higher in the giant LST group than the small LST group ( P =0.001). Moreover, for giant rectal LSTs, the growth pattern of the lesion, JNET classification, and the extent of postoperative mucosal defect do not significantly affect the efficacy of ESD. It is worth mentioning that the operation time was longer in the group with a diameter >5 cm, in which perforation was more frequent and the muscle layer was more likely to be injured during ESD ( P <0.001). The muscle injury during ESD was mainly related to the diameter of the lesion, the crossing the rectal pouch, and the operation time. CONCLUSIONS: The use of ESD to treat giant rectal LSTs (>5 cm) is relatively difficult and can easily lead to intraoperative muscle injury, perforation, and late postoperative bleeding. However, if active intervention is performed, patients can still achieve good efficacy and prognosis, which can be applied in hospitals with certain conditions.

Endoscopic En Bloc Versus Piecemeal Resection of Large Nonpedunculated Colonic Adenomas : A Randomized Comparative Trial.

BACKGROUND: Endoscopic resection of adenomas prevents colorectal cancer, but the optimal technique for larger lesions is controversial. Piecemeal endoscopic mucosal resection (EMR) has a low adverse event (AE) rate but a variable recurrence rate necessitating early follow-up. Endoscopic submucosal dissection (ESD) can reduce recurrence but may increase AEs. OBJECTIVE: To compare ESD and EMR for large colonic adenomas. DESIGN: Participant-masked, parallel-group, superiority, randomized controlled trial. (ClinicalTrials.gov: NCT03962868). SETTING: Multicenter study involving 6 French referral centers from November 2019 to February 2021. PARTICIPANTS: Patients with large (≥25 mm) benign colonic lesions referred for resection. INTERVENTION: The patients were randomly assigned by computer 1:1 (stratification by lesion location and center) to ESD or EMR. MEASUREMENTS: The primary end point was 6-month local recurrence (neoplastic tissue on endoscopic assessment and scar biopsy). The secondary end points were technical failure, en bloc R0 resection, and cumulative AEs. RESULTS: In total, 360 patients were randomly assigned to ESD (n = 178) or EMR (n = 182). In the primary analysis set (n = 318 lesions in 318 patients), recurrence occurred after 1 of 161 ESDs (0.6%) and 8 of 157 EMRs (5.1%) (relative risk, 0.12 [95% CI, 0.01 to 0.96]). No recurrence occurred in R0-resected cases (90%) after ESD. The AEs occurred more often after ESD than EMR (35.6% vs. 24.5%, respectively; relative risk, 1.4 [CI, 1.0 to 2.0]). LIMITATION: Procedures were performed under general anesthesia during hospitalization in accordance with the French health system. CONCLUSION: Compared with EMR, ESD reduces the 6-month recurrence rate, obviating the need for systematic early follow-up colonoscopy at the cost of more AEs. PRIMARY FUNDING SOURCE: French Ministry of Health.

Low delayed bleeding and high complete closure rate of mucosal defects with the novel through-the-scope dual-action tissue clip after endoscopic resection of large nonpedunculated colorectal lesions (with video).

BACKGROUND AND AIMS: Complete closure after endoscopic resection of large nonpedunculated colorectal lesions (LNPCLs) can reduce delayed bleeding but is challenging with conventional through-the-scope (TTS) clips alone. The novel dual-action tissue (DAT) clip has clip arms that open and close independently of each other, facilitating tissue approximation. We aimed to evaluate the rate of complete closure and delayed bleeding with the DAT clip after endoscopic resection of LNPCLs. METHODS: This was a multicenter prospective cohort study of all patients who underwent defect closure with the DAT clip after EMR or endoscopic submucosal dissection (ESD) of LNPCLs ≥20 mm from July 2022 to May 2023. Delayed bleeding was defined as a bleeding event requiring hospitalization, blood transfusion, or any intervention within 30 days after the procedure. Complete closure was defined as apposition of mucosal defect margins without visible submucosal areas <3 mm along the closure line. RESULTS: One hundred seven patients (median age, 64 years; 42.5% women) underwent EMR (n = 63) or ESD (n = 44) of LNPCLs (median size, 40 mm; 74.8% right-sided colon) followed by defect closure. Complete closure was achieved in 96.3% (n = 103) with a mean of 1.4 ± .6 DAT clips and 2.9 ± 1.8 TTS clips. Delayed bleeding occurred in 1 patient (.9%) without requiring additional interventions. CONCLUSIONS: The use of the DAT clip in conjunction with TTS clips achieved high complete defect closure after endoscopic resection of large LNPCLs and was associated with a .9% delayed bleeding rate. Future comparative trials and formal cost-analyses are needed to validate these findings. (Clinical trial registration number: NCT05852457.).

The feasibility of endoscopic resection for colorectal laterally spreading tumors.

The present study aimed to investigate the feasibility and safety of endoscopic resection for colorectal laterally spreading tumors (LSTs) in different size groups. This retrospective study included 2699 patients with LSTs who underwent endoscopic treatment at the Second Xiangya Hospital of Central South University from May 2012 to February 2022. The patient baseline and procedure outcomes were compared between the < 5 cm group, 5-10 cm group, and ≥ 10 cm group. Meanwhile, lesions larger than 5 cm in diameter were longitudinally compared for endoscopic safety using ESD with surgical operation outcomes. There were 2105 patients in the < 5 cm group, 547 patients in the 5-10 cm group, and 47 patients in the ≥ 10 cm group. En bloc resection and R0 resection rates, the incidence of adverse events, length of stay (LOS), and medical costs significantly differed between the groups (P < 0.01). Comorbidity of diabetes or hypertension, history of antithrombotic drug use, lesion size, location, gross type, endoscopic procedures selection, and circumferential extent of the mucosal defect were independent risk factors for delayed bleeding (P < 0.05). En bloc resection, R0 resection, and lesion canceration were associated with local recurrence. For lesions larger than 5 cm in diameter, ESD had similar R0 resection and local recurrence rates compared with a surgical operation but a lower en bloc rate, LOS, and medical costs. Expert endoscopists can significantly increase en bloc and R0 resection rates and reduce the incidence of adverse events. Endoscopic resection results distinguish in different size groups of colorectal LSTs, yet its safety and feasibility are not inferior to a surgical operation.

Continuous suture technique increases the complete closure rate of colorectal mucosal defects after endoscopic resection: a single-blind, randomized controlled trial.

BACKGROUND: Complete closure of mucosal defects after colorectal endoscopic submucosal dissection (ESD)/piecemeal endoscopic mucosal resection (p-EMR) procedures reduces postoperative adverse events, but the complete closure rate of the traditional method using only hemostatic clips is not satisfactory. Therefore, we invented a continuous suture technique using a barbed suture and clips to increase the complete closure rate of colorectal mucosal defects. METHODS: Patients with a single large (≥ 2 cm) colorectal lesion were recruited. After completion of the ESD/p-EMR procedures, they were randomly allocated to the treatment group or control group. The mucosal defects of the treatment group were closed using barbed suture and clips, while the control group was closed using only clips. RESULTS: From January 18, 2022 to April 13, 2022, a total of 62 patients with colorectal lesions were enrolled, with 31 patients in each group. Complete closure was achieved in 29 patients (93.5%) in the treatment group and 18 patients (58.1%) in the control group (P = 0.001). The median closure time was 13 min in the treatment group and 19 min in the control group (P < 0.001). The median closure speed was 6.4 cm2/10 min in the treatment group and 3.5 cm2/10 min in the control group (P = 0.008). CONCLUSIONS: This study provided a clinically feasible continuous suture technique that was safe and effective for the complete closure of colorectal mucosal defects after endoscopic resection.

Underwater versus conventional endoscopic mucosal resection for colorectal lesions: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND & AIMS: Conventional endoscopic mucosal resection (CEMR) is the established method for the resection of non-pedunculated colorectal lesions (NPCRL) ≥ 10 mm. In the last decade, underwater endoscopic mucosal resection (UEMR) has been introduced as a potential alternative. The aim of this systematic review with meta-analysis is to compare the recurrence and safety of UEMR and CEMR by analyzing only randomized controlled trials (RCTs). METHODS: We systematically searched PubMed, Cochrane Library and EMBASE until April 2023. Studies met the following inclusion criteria: (1) RCTs, (2) comparing UEMR with CEMR, (3) NPCRL ≥ 10 mm, and (4) reporting the outcomes of interest. Primary outcomes were recurrence and safety. Secondary outcomes were en bloc, R0, complete resection, clipping and adverse events per type. RESULTS: Five RCTs were included. UEMR was associated with a lower recurrence rate (OR: 0.56; 95% CI: 0.32-0.97). Thus, the RR of recurrence was 1.7 times higher in the CEMR group (95% CI, 1.04-2.77). There was no significant difference in the pooled safety analysis. UEMR showed better en bloc resection rates (OR: 1.54; 95% CI: 1.15-2.07), but subgroup analysis showed comparable rates in lesions ≥ 20 mm. R0 resection was higher in UEMR (OR: 1.72; 95% CI: 1.23-2.41). Other outcomes were not different between the 2 groups. CONCLUSIONS: UEMR is as safe as CEMR, with a higher overall R0 rate and a higher en bloc resection rate for lesions < 20 mm, leading to a lower overall recurrence rate. The results of this meta-analysis support the widespread use of UEMR.

Cap-assisted endoscopic mucosal resection as a salvage technique for challenging colorectal laterally spreading tumors.

BACKGROUND: Cap-assisted endoscopic mucosal resection (EMR-c) has emerged as a potential alternative to standard piecemeal wide-field EMR (WF-EMR) for the resection of laterally spreading tumors (LSTs). However, clear indications for this technique are still lacking. Our objective was to investigate the performance of salvage EMR-c after WF-EMR failure in the resection of large colorectal LSTs. METHODS: The data of consecutive patients undergoing WF-EMR for large colorectal LSTs (2015-2021) were analyzed in this single-center, retrospective, observational study. In the event of a WF-EMR failure, the procedure was switched to EMR-c in the same session. The efficacy of the two techniques was evaluated in terms of complete endoscopic resection, R0 resection, and recurrence rate. Safety was also assessed. RESULTS: Overall, the data from 81 WF-EMRs were collected. Eighteen cases of WF-EMR failure were switched to EMR-c in the same session and complete endoscopic resection was achieved in 17/18 patients (94.4%). No statistically significant difference was observed between WF-EMR and salvage EMR-c in terms of macroscopic radicality (P = 0.40) and R0 resection (P = 0.12). However, recurrence was more common with EMR-c (44.4% vs. 23.5%; P = 0.05), as were adverse events, particularly intraprocedural bleeding (27.8% vs. 7.9%; P = 0.04). CONCLUSION: EMR-c is an effective salvage technique for challenging colorectal LSTs following WF-EMR failure. Due to the elevated risk of adverse events associated with this procedure, careful patient selection, endoscopic expertise, and close follow-up are strongly recommended.

Is colorectal endoscopic submucosal dissection safe and effective for 15-19-mm tumors?

PURPOSE: The outcomes of colorectal endoscopic submucosal dissection (ESD) in 15-19-mm tumors are unclear. This study compared the effectiveness and safety of colorectal ESD for 15-19-mm tumors and tumors exceeding that size. METHODS: From August 2018 to December 2020, 213 cases of colorectal tumors removed by colorectal ESD at a tertiary hospital were enrolled in this study. The cases were divided into two groups according to the pathologically measured size of the resected lesion: an intermediate group (15-19 mm, n = 62) and a large group (≥ 20 mm, n = 151). The en bloc resection rate, complete resection rate, and complications were investigated retrospectively. RESULTS: The en bloc resection rate was significantly higher in the intermediate than large group (100% vs. 94%, p = 0.049), and the mean total procedure time was shorter in the intermediate than large group (29.2 [Formula: see text] 12.6 vs. 48.4 [Formula: see text] 28.8 min, p < 0.001). However, the mean procedure speed was significantly lower in the intermediate than large group (0.25 [Formula: see text] 0.10 vs. 0.28 [Formula: see text] 0.11 cm2/min, p = 0.031). The complete resection rate, post-procedural bleeding, and perforation rate were not significantly different between the two groups. In multivariate analyses, the total procedure time and mean procedure speed were significantly associated with lesion size. CONCLUSION: Colorectal ESD of 15-19-mm lesions is effective, and has a shorter procedure time and higher en bloc resection rate than the same procedure for larger lesions.

Endoscopic mucosal resection and endoscopic submucosal dissection with an external additional working channel (EMR+ and ESD+) are equivalent to using a double-channel endoscope: a systematic evaluation in a porcine ex vivo model.

BACKGROUND AND AIMS: With an external additional working channel (AWC) endoscopic mucosal resection (EMR) as well as endoscopic submucosal dissection (ESD) can be extended to techniques termed "EMR+" and "ESD+." These novel techniques are systematically compared to EMR and ESD under the use of a double-channel endoscope (DC). METHODS: Our trial was conducted prospectively in a pre-clinical porcine animal model (EASIE-R simulator) with standardized gastric lesions measuring 3 or 4 cm. RESULTS: EMR+ and EMR DC showed both good results for 3 cm lesions with no adverse events and an en bloc resection rate of 73.33% (EMR+) and 60.00% (EMR DC, p = 0.70). They came to their limits in 4 cm lesions with muscularis damages of 20.00% (EMR+), 13.33% (EMR DC, p ≥ 0.99) and decreasing en bloc resection rates of 60.00% (EMR+) and 46.67% (EMR DC, p = 0.72). ESD+ and ESD DC were both reliable concerning en bloc resection rates (100% in all groups) and adverse events (0.00% in 3 cm lesions, 12.50% muscularis damages in both ESD+ and ESD DC in 4 cm lesions). Resection time was slightly shorter in all groups with the AWC compared to DC although only reaching significance in 3 cm ESD lesions (p < 0.05*). CONCLUSIONS: With the AWC, a standard endoscope can easily be transformed to double-channel functionality. We could show that EMR+ and ESD+ are non-inferior to EMR and ESD under the use of a double-channel endoscope. Consequently, the AWC presents an affordable alternative to a double-channel endoscope for both EMR and ESD.