Establishment of Standards for the Referral of Large Non-Pedunculated Colorectal Polyps: An International Expert Consensus Using a Modified Delphi Process.

BACKGROUND AND AIMS: Resection of colorectal polyps has been shown to decrease the incidence and mortality of colorectal cancer. Large non-pedunculated colorectal polyps are often referred to expert centres for endoscopic resection, which requires relevant information to be conveyed to the therapeutic endoscopist to allow for triage and planning of resection technique. The primary objective of our study was to establish minimum expected standards for the referral of LNPCP for potential ER. METHODS: A Delphi methodology was employed to establish consensus on minimum expected standards for the referral of large colorectal polyps among a panel of international endoscopy experts. The expert panel was recruited through purposive sampling, and three rounds of surveys were conducted to achieve consensus, with quantitative and qualitative data analysed for each round. RESULTS: A total of 24 international experts from diverse continents participated in the Delphi study, resulting in consensus on 19 statements related to the referral of large colorectal polyps. The identified factors, including patient demographics, relevant medications, lesion factors, photodocumentation and the presence of a tattoo, were deemed important for conveying the necessary information to therapeutic endoscopists. The mean scores for the statements ranged from 7.04 to 9.29 out of 10, with high percentages of experts considering most statements as a very high priority. Subgroup analysis by continent revealed some variations in consensus rates among experts from different regions. CONCLUSION: The identified consensus statements can aid in improving the triage and planning of resection techniques for large colorectal polyps, ultimately contributing to the reduction of colorectal cancer incidence and mortality.

Development and validation of artificial neural networks model for detection of Barrett's neoplasia: a multicenter pragmatic nonrandomized trial (with video).

BACKGROUND AND AIMS: The aim of this study was to develop and externally validate a computer-aided detection (CAD) system for the detection and localization of Barrett's neoplasia and assess its performance compared with that of general endoscopists in a statistically powered multicenter study by using real-time video sequences. METHODS: In phase 1, the hybrid visual geometry group 16-SegNet model was trained by the use of 75,198 images and videos (96 patients) of neoplastic and 1,014,973 images and videos (65 patients) of nonneoplastic Barrett's esophagus. In phase 2, image-based validation was performed on a separate dataset of 107 images (20 patients) of neoplastic and 364 images (14 patients) of nonneoplastic Barrett's esophagus. In phase 3 (video-based external validation) we designed a real-time video-based study with 32 videos (32 patients) of neoplastic and 43 videos (43 patients) of nonneoplastic Barrett's esophagus from 4 European centers to compare the performance of the CAD model with that of 6 nonexpert endoscopists. The primary endpoint was the sensitivity of CAD diagnosis of Barrett's neoplasia. RESULTS: In phase 2, CAD detected Barrett's neoplasia with sensitivity, specificity, and accuracy of 95.3%, 94.5%, and 94.7%, respectively. In phase 3, the CAD system detected Barrett's neoplasia with sensitivity, specificity, negative predictive value, and accuracy of 93.8%, 90.7%, 95.1%, and 92.0%, respectively, compared with the endoscopists' performance of 63.5%, 77.9%, 74.2%, and 71.8%, respectively (P < .05 in all parameters). The CAD system localized neoplastic lesions with accuracy, mean precision, and mean intersection over union of 100%, 0.62, and 0.54, respectively, when compared with at least 1 of the expert markings. The processing speed of the CAD detection and localization were 5 ms/image and 33 ms/image, respectively. CONCLUSION: To our knowledge, this is the first study describing external (multicenter) validation of AI algorithms for the detection of Barrett's neoplasia on real-time endoscopic videos. The CAD system in this study significantly outperformed nonexpert endoscopists on real-time video-based assessment, achieving >90% sensitivity for neoplasia detection. This result needs to be validated during real-time endoscopic assessment.

Predictors of long-term outcomes of endoscopic submucosal dissection of early gastric neoplasia in the West: a multicenter study.

BACKGROUND: This study aimed to determine long-term outcomes of gastric endoscopic submucosal dissection (ESD) in Western settings based on the latest Japanese indication criteria, and to examine predictors of outcomes and complications. METHODS: Data were collected from consecutive patients undergoing gastric ESD at four participating centers from 2009 to 2021. Retrospective analysis using logistic regression and survival analysis was performed. RESULTS: 415 patients were included (mean age 71.7 years; 56.4 % male). Absolute indication criteria (2018 guideline) were met in 75.3 % of patients. Median follow-up was 52 months. Post-resection histology was adenocarcinoma, high grade dysplasia, and low grade dysplasia in 49.9 %, 22.7 %, and 17.1 %, respectively. Perforation, early and delayed bleeding occurred in 2.4 %, 4.3 %, and 3.4 %, respectively. Rates of en bloc and R0 resection, and recurrence on first endoscopic follow-up were 94.7 %, 83.4 %, and 2.7 %, respectively. Relative indication (2018 guideline) for ESD was associated with R1 outcome (P = 0.02). Distal location (P = 0.002) and increased procedure time (P = 0.04) were associated with bleeding, and scarring (P = 0.009) and increased procedure duration (P = 0.003) were associated with perforation. Recurrence-free survival at 2 and 5 years was 94 % and 83 %, respectively. CONCLUSION: This is the largest Western multicenter cohort and suggests that gastric ESD is safe and effective in the Western setting. A quarter of patients fell outside the new absolute indications for ESD, suggesting that Western practice involves more advanced lesions. We identified the predictors of complications, which should help to inform future Western practice and research.

Randomized controlled trial of EndoRings assisted colonoscopy versus standard colonoscopy.

OBJECTIVES: The EndoRings device is a distal attachment consisting of two layers of circular flexible rings that evert mucosal folds. The aim of this study was to investigate whether EndoRing assisted colonoscopy (ER) improves polyp and adenoma detection compared to standard colonoscopy (SC). METHODS: Multicenter, parallel group, randomized controlled trial. RESULTS: Total of 556 patients randomized to ER (n = 275) or SC (n = 281). Colonoscopy completed in 532/556 (96%) cases. EndoRings removed in 74/275 (27%) patients. Total number of polyps in ER limb 582 vs. 515 in SC limb, P = 0.04. Total number of adenomas in ER limb 361 vs. 343 for SC limb, P = 0.49. A statistically significant difference in the mean number of polyps per patient in both the intention to treat (1.84 SC vs. 2.10 ER, P = 0.027) and per protocol (PP) (1.84 SC vs. 2.25 ER, P = 0.004). CONCLUSIONS: Our study shows promise for the EndoRings device to improve polyp detection.

Clinical outcome of non-curative endoscopic submucosal dissection for early colorectal cancer.

OBJECTIVE: Endoscopic submucosal dissection (ESD) in a curative intent for submucosa-invasive early (T1) colorectal cancers (T1-CRCs) often leads to subsequent surgical resection in case of histologic parameters indicating higher risk of nodal involvement. In some cases, however, the expected benefit may be offset by the surgical risks, suggesting a more conservative approach. DESIGN: Retrospective analysis of consecutive patients with T1-CRC who underwent ESD at 13 centres ending inclusion in 2019 (n=3373). Cases with high risk of nodal involvement (non-curative ESD: G3, submucosal invasion>1000 µm, lymphovascular involvement, budding or incomplete resection/R1) were analysed if follow-up data (endoscopy/imaging) were available, regardless of the postendoscopic management (follow-up vs surgery) selected by the multidisciplinary teams in these institutions. Comorbidities were classified according to Charlson Comorbidity Index (CCI). Outcomes were disease recurrence, death and disease-related death rates in the two groups. Rate of residual disease (RD) at both the previous resection site and regional lymph nodes was assessed in the surgical cases as well as from follow-up in the follow-up group. RESULTS: Of 604 patients treated by colorectal ESD for submucosally invasive cancer, 207 non-curative resections (34.3%) were included (138 male; mean age 67.6±10.9 years); in 65.2% of cases, no complete resection was achieved (R1). Of the 207 cases, 60.9% (n=126; median CCI: 3; IQR: 2-4) underwent surgical treatment with RD in 19.8% (25/126), while 39.1% (n=81, median CCI: 5; IQR: 4-6) were followed up by endoscopy in all cases. Patients in the follow-up group had a higher overall mortality (HR=3.95) due to non-CRC causes (n=9, mean survival after ESD 23.7±13.7 months). During this follow-up time, tumour recurrence and disease-specific survival rates were not different between the groups (median follow-up 30 months; range: 6-105). CONCLUSION: Following ESD for a lesion at high risk of RD, follow-up only may be a reasonable choice in patients at high risk for surgery. Also, endoscopic resection quality should be improved. TRIAL REGISTRATION NUMBER: NCT03987828.

Sporadic non-ampullary duodenal adenomas: efficacy and outcomes of endoscopic resection.

BACKGROUND AND AIMS: Sporadic non-ampullary duodenal adenomas (SNDAs) are often referred to tertiary centers because of the challenges in endoscopic resection. There is a paucity of data on both technical and clinical outcomes. The aim of our study was to evaluate the efficacy and safety of endoscopic resection for the treatment of SNDA in two western centers. METHODS: This is a retrospective study reporting data of a cohort of patients referred for resection of SNDA between 2013 and 2017. Patients with familial adenomatous polyposis or ampullary lesions were excluded from present analysis. Outcomes considered for this study were technical success, adverse events, recurrence and need for surgery. RESULTS: 120 patients (mean age 66 ± 11.9 years, 64male) were enrolled in the study. Mean size of the lesions was 23.3 mm (range 5-80). Fifty-six en-bloc endoscopic mucosal resection (EMR) (46.6%), 41 piecemeal EMR (pEMR) and 23 endoscopic submucosal dissection were performed. Intra-procedural perforation was observed in 4 patients (3.3%). Fourteen post-procedural (11.6%) adverse events were recorded. All post-procedural perforations occurred in lesions > 30 mm. Recurrence was observed in 11 patients (9.5%) during a mean follow-up of 29 months. All recurrences were successfully managed endoscopically. 119 patients were still alive at last follow-up. CONCLUSION: Endoscopic resection can be successfully carried out in majority of patients. Size > 30 mm seems to be the predictor of high adverse events risk.

Efficacy of Real-Time Computer-Aided Detection of Colorectal Neoplasia in a Randomized Trial.

BACKGROUND & AIMS: One-fourth of colorectal neoplasias are missed during screening colonoscopies; these can develop into colorectal cancer (CRC). Deep learning systems allow for real-time computer-aided detection (CADe) of polyps with high accuracy. We performed a multicenter, randomized trial to assess the safety and efficacy of a CADe system in detection of colorectal neoplasias during real-time colonoscopy. METHODS: We analyzed data from 685 subjects (61.32 ± 10.2 years old; 337 men) undergoing screening colonoscopies for CRC, post-polypectomy surveillance, or workup due to positive results from a fecal immunochemical test or signs or symptoms of CRC, at 3 centers in Italy from September through November 2019. Patients were randomly assigned (1:1) to groups who underwent high-definition colonoscopies with the CADe system or without (controls). The CADe system included an artificial intelligence-based medical device (GI-Genius, Medtronic) trained to process colonoscopy images and superimpose them, in real time, on the endoscopy display a green box over suspected lesions. A minimum withdrawal time of 6 minutes was required. Lesions were collected and histopathology findings were used as the reference standard. The primary outcome was adenoma detection rate (ADR, the percentage of patients with at least 1 histologically proven adenoma or carcinoma). Secondary outcomes were adenomas detected per colonoscopy, non-neoplastic resection rate, and withdrawal time. RESULTS: The ADR was significantly higher in the CADe group (54.8%) than in the control group (40.4%) (relative risk [RR], 1.30; 95% confidence interval [CI], 1.14-1.45). Adenomas detected per colonoscopy were significantly higher in the CADe group (mean, 1.07 ±1.54) than in the control group (mean 0.71 ± 1.20) (incidence rate ratio, 1.46; 95% CI, 1.15-1.86). Adenomas 5 mm or smaller were detected in a significantly higher proportion of subjects in the CADe group (33.7%) than in the control group (26.5%; RR, 1.26; 95% CI, 1.01-1.52), as were adenomas of 6 to 9 mm (detected in 10.6% of subjects in the CADe group vs 5.8% in the control group; RR, 1.78; 95% CI, 1.09-2.86), regardless of morphology or location. There was no significant difference between groups in withdrawal time (417 ± 101 seconds for the CADe group vs 435 ± 149 for controls; P = .1) or proportion of subjects with resection of non-neoplastic lesions (26.0% in the CADe group vs 28.7% of controls; RR, 1.00; 95% CI, 0.90-1.12). CONCLUSIONS: In a multicenter, randomized trial, we found that including CADe in real-time colonoscopy significantly increases ADR and adenomas detected per colonoscopy without increasing withdrawal time. ClinicalTrials.gov no: 04079478.

A novel self-assembling peptide for hemostasis during endoscopic submucosal dissection: a randomized controlled trial.

BACKGROUND: Endoscopic submucosal dissection (ESD) is associated with a risk of bleeding. Bleeding is usually treated with diathermy, although this does carry a risk of mucosal thermal injury. Purastat is a topical hemostat that may be effective in controlling bleeding during ESD, thereby reducing the use of heat therapy. The aim of this study was to assess the reduction in heat therapy used in the interventional group (Purastat) compared with the control group. The secondary aims were to compare the procedure length, time for hemostasis, delayed bleeding rate, adverse events, and wound healing between the groups. METHODS: This was a single-center randomized controlled trial of 101 patients undergoing ESD. Participants were randomized to a control group where diathermy was used to control bleeding or an interventional group where Purastat could be used. Follow-up endoscopy was performed at 4 weeks to assess wound healing. RESULTS: There was a significant reduction in the use of heat therapy for intraprocedural hemostasis in the interventional group compared with controls (49.3 % vs. 99.6 %, P < 0.001). There were no significant differences in the procedure length, time for hemostasis, and delayed bleeding rate between the groups. Complete wound healing at 4 weeks was noted in 48.8 % of patients in the interventional group compared with 25.0 % of controls (P = 0.02). CONCLUSIONS: This study has demonstrated that Purastat is an effective hemostat that can reduce the need for heat therapy for bleeding during ESD. It may also have a role in improving post-resection wound healing.

Recovery of endoscopy services in the era of COVID-19: recommendations from an international Delphi consensus.

The COVID-19 pandemic has had a profound impact on provision of endoscopy services globally as staff and real estate were repurposed. As we begin to recover from the pandemic, a cohesive international approach is needed, and guidance on how to resume endoscopy services safely to avoid unintended harm from diagnostic delays. The aim of these guidelines is to provide consensus recommendations that clinicians can use to facilitate the swift and safe resumption of endoscopy services. An evidence-based literature review was carried out on the various strategies used globally to manage endoscopy during the COVID-19 pandemic and control infection. A modified Delphi process involving international endoscopy experts was used to agree on the consensus statements. A threshold of 80% agreement was used to establish consensus for each statement. 27 of 30 statements achieved consensus after two rounds of voting by 34 experts. The statements were categorised as pre-endoscopy, during endoscopy and postendoscopy addressing relevant areas of practice, such as screening, personal protective equipment, appropriate environments for endoscopy and infection control precautions, particularly in areas of high disease prevalence. Recommendations for testing of patients and for healthcare workers, appropriate locations of donning and doffing areas and social distancing measures before endoscopy are unique and not dealt with by any other guidelines. This international consensus using a modified Delphi method to produce a series of best practice recommendations to aid the safe resumption of endoscopy services globally in the era of COVID-19.

Development and validation of the international Blue Light Imaging for Barrett's Neoplasia Classification.

BACKGROUND AND AIMS: Detecting subtle Barrett's neoplasia during surveillance endoscopy can be challenging. Blue-light imaging (BLI) is a novel advanced endoscopic technology with high-intensity contrast imaging that may improve the identification of Barrett's neoplasia. The aim of this study was to develop and validate the first classification to enable characterization of neoplastic and non-neoplastic Barrett's esophagus using BLI. METHODS: In phase 1, descriptors pertaining to neoplastic and non-neoplastic Barrett's esophagus were identified to form the classification, named the Blue Light Imaging for Barrett's Neoplasia Classification (BLINC). Phase 2 involved validation of these component criteria by 10 expert endoscopists assessing 50 BLI images. In phase 3, a web-based training module was developed to enable 15 general (nonexpert) endoscopists to use BLINC. They then validated the classification with an image assessment exercise in phase 4, and their pre- and post-training results were compared. RESULTS: In phase 1 the descriptors were grouped into color, pit, and vessel pattern categories to form the classification. In phase 2 the sensitivity of neoplasia identification was 96.0% with a very good level of agreement among the experts (κ = .83). In phase 3, 15 general endoscopists completed the training module. In phase 4 their pretraining sensitivity (85.3%) improved significantly to 95.7% post-training with a good level of agreement (κ = .67). CONCLUSIONS: We developed and validated a new classification system (BLINC) for the optical diagnosis of Barrett's neoplasia using BLI. Despite the limitations of this image-based study with a high prevalence of neoplasia, we believe it has the potential to improve the optical diagnosis of Barrett's neoplasia given the high degree of sensitivity (96%) noted. It is also a promising tool for training in Barrett's esophagus optical diagnosis using BLI.

Computer-aided detection-assisted colonoscopy: classification and relevance of false positives.

BACKGROUND AND AIMS: False positive (FP) results by computer-aided detection (CADe) hamper the efficiency of colonoscopy by extending examination time. Our aim was to develop a classification of the causes and clinical relevance of CADe FPs, and to assess the relative distribution of FPs in a real-life setting. METHODS: In a post-hoc analysis of a randomized trial comparing colonoscopy with and without CADe (NCT: 04079478), we extracted 40 CADe colonoscopy videos. Using a modified Delphi process, 4 expert endoscopists identified the main domains for the reasons and clinical relevance of FPs. Then, 2 expert endoscopists manually examined each FP and classified it according to the proposed domains. The analysis was limited to the withdrawal phase. RESULTS: The 2 main domains for the causes of CADe FPs were identified as artifacts due to either the mucosal wall or bowel content, and clinical relevance was defined as the time spent on FPs and the FP rate per minute. The mean number of FPs per colonoscopy was 27.3 ± 13.1, of which 24 ± 12 (88%) and 3.2 ± 2.6 (12%) were due to artifacts in the bowel wall and bowel content, respectively. Of the 27.3 FPs per colonoscopy, 1.6 (5.7%) required additional exploration time of 4.8 ± 6.2 seconds per FP (ie, 0.7% of the mean withdrawal time). In detail, 15 (24.2%), 33 (53.2%), and 14 (22.6%) FPs were classified as being of mild, moderate, or severe clinical relevance. The rate of FPs per minute of withdrawal time was 2.4 ± 1.2, and was higher for FPs due to artifacts from the bowel wall than for those from bowel content (2.4 ± 0.6 vs 0.3 ± 0.2, P < .001). CONCLUSIONS: FPs by CADe are primarily due to artifacts from the bowel wall. Despite a high frequency, FPs result in a negligible 1% increase in the total withdrawal time because most of them are immediately discarded by the endoscopist.

Multi-band mucosectomy for neoplasia in patients with Barrett's esophagus: in vivo comparison between two different devices.

BACKGROUND: Multi-band mucosectomy (MBM) is effective and safe for Barrett's neoplasia. No studies have yet compared the efficacy and safety of the MBM devices commercially available: Duette™ (CookMedical) and Captivator™ (BostonScientific). Our aim is to compare the two devices. METHODS: This is a dual-center retrospective case-control study (Rozzano, Portsmouth) comparing efficacy, safety, and histology of resected specimens between Duette™ (DUE) and Captivator™ (CAPT). Efficacy was assessed by R0 and local recurrence (LR) rate. Bleedings, perforations, and strictures were recorded as safety outcomes. Moreover, the specimens were re-examined by two pathologists, blinded about the study group, to assess the maximum thickness of both the whole specimens and the resected submucosal layer. RESULTS: Seventy-six patients (38 per group) were included. The two groups did not differ in terms of baseline characteristics. R0 resection was achieved in 96.7% versus 96.3% (p = ns) and LR were recorded in 4/38 (10.5%) versus 3/38 (7.9%) in DUE and CAPT group, respectively (p = ns). Considering Duette™ versus Captivator™, 2 versus 3 patients developed a symptomatic stricture. Only one post-procedural bleeding occurred (Captivator™). Maximum medium thicknesses of specimens and of resected submucosa did not differ between the groups. CONCLUSIONS: MBM is safe and effective for resecting visible lesions using either of the two available devices.

Future of Endoscopy: Brief review of current and future endoscopic resection techniques for colorectal lesions.

Endoscopic treatment of colorectal lesions has seen major developments in the last decade. It is now considered curative for intramucosal and superficial submucosal cancers. Endoscopic Mucosal Resection in expert hands has very good outcomes with low complication rates but recurrence and inadequate treatment of early cancers remain an issue. This has led to a technical evolution that can lead to one piece resection of neoplasia. This includes a range of techniques from knife assisted snare resection (KAR), endoscopic submucosal dissection (ESD) to full thickness resections. This article reviews all the resection techniques and the evidence base behind them.

Endoscopic management of intraprocedural bleeding during endoscopic interventions.

Endoscopic resection techniques have evolved over time, allowing effective and safe resection of the majority of pre-malignant and early cancerous lesions in the gastrointestinal tract. Bleeding is one of the most commonly encountered complications during endoscopic resection, which can interfere with the procedure and result in serious adverse events. Intraprocedural bleeding is relatively common during endoscopic resection and, in most cases, is a mild and self-limiting event. However, it can interfere with the completion of the resection and may result in negative patient-related outcomes in severe cases, including the need for hospitalization and blood transfusion as well as the requirement for radiological or surgical interventions. Appropriate management of intraprocedural bleeding can improve the safety and efficacy of endoscopic resection, and it can be readily achieved with the use of several endoscopic hemostatic tools. In this review, we discuss the recent advances in the approach to intraprocedural bleeding complicating endoscopic resection, with a focus on the various endoscopic hemostatic tools available to manage such events safely and effectively.

Cold-snare endoscopic resection of non-ampullary duodenal adenomas: Systematic review and pooled-analysis.

BACKGROUND: Mirroring the experience with colonic resections, cold snare-based techniques have been recently proposed for non-ampullary duodenal lesions to reduce the risk of adverse events (AEs). As the duodenal wall is thinner and more vascularized than in the colon, electrocautery-related AEs are relevant issues in this setting. AIMS: We performed a systematic review with pooled-analysis to evaluate the efficacy and safety of this technique. METHODS: Electronic databases (Medline, Scopus, EMBASE) were searched up to January 2023. Full articles including patients with duodenal lesions resected by cold-snare technique were eligible. The adverse events (i.e., bleeding, perforation, stricture), complete resection, and recurrence rates were pooled using a random model. RESULTS: Eleven studies were eligible, providing data on 3137 lesions removed from 233 patients. The overall AE rate for cold snaring was 0.25% (95% CI, 0.19%-0.69%). Among the three studies comparing cold- and hot-snare approaches, procedure-related bleeding rate was significantly lower with cold approach (OR 1.21, 0.51-2.85; p = 0.66). The complete resection rate was 99.40% (95% CI, 98.60%-100%), with a residual/recurrence rate of 12.95% (95% CI, 4.75%-21.16%). On univariate meta-regression, lesion size significantly affected both the adverse events and recurrence risk. CONCLUSION: Cold-snare resection appears effective and extremely safe for resecting non-ampullary duodenal lesions.

Staying (Mentally) Healthy: The Impact of COVID-19 on Personal and Professional Lives.

COVID-19 pandemic has played havoc at various levels throughout the world but has especially impacted the Health care professionals and put them at risk of mental ill health. The morbidity, mortality, and financial impact of COVID-19 have been huge and can easily dwarf the issues about mental wellbeing of individuals during these tough times. This can potentially have a long-lasting impact resulting in delayed recovery from this pandemic on all fronts of life. In our review, we aim to explore the issue of mental health with particular emphasis on health care workers and try and understand the size of problems, the symptoms and specific causes pertaining to COVID-19 related mental ill health. Finally, we have summarized some of the measures that can be taken by institutions and individuals to minimize the impact of COVID-19 pandemic on our mental wellbeing.

Submucosal tunnelling techniques for Zenker's diverticulum: a systematic review of early outcomes with pooled analysis.

In the last decade, flexible endoscopic septotomy has been reported as a well-tolerated and effective treatment for Zenker's diverticulum. More recently, novel endoscopic submucosal tunneling techniques, namely Zenker-PerOral Endoscopic Myotomy (Z-POEM) and PerOral Endoscopic Septotomy (POES) have been proposed to obtain complete muscular septum exposure and deeper myotomy. The aim of this study is to provide a systematic review with a meta-analysis of the first experiences of third space approaches for Zenker's diverticulum. Electronic databases (Medline, Scopus, EMBASE) were searched up to October 2020. Studies including patients with symptomatic Zenker's diverticulum who underwent endoscopic treatment by submucosal tunneling technique were eligible. Procedural, clinical and safety outcomes were assessed by pooling data with a random-effect model to obtain a proportion with a 95% confidence interval. Nine retrospective studies were eligible for inclusion (196 patients). Five studies were performed in the USA, two in Europe and two in Asia. Endoscopic treatment was feasible in 96.9% (I2 = 0%) of patients. The mean procedure duration was 36.4 ± 14.3 minutes. Clinical success was achieved after 93.4% (I2 = 0%) of procedures. The overall adverse events rate was 4.9% (I2 = 0%). No differences between the two approaches (Z-POEM vs POES) have been shown in terms of both efficacy and safety. Submucosal tunneling techniques appear to be feasible for symptomatic Zenker's diverticulum, with promising results in terms of efficacy and safety outcomes.