CEACAM5 and TROP2 define metaplastic and dysplastic transitions in human antral gastric precancerous lesions and tumors.

BACKGROUND: Mucosal gastric atrophy and intestinal metaplasia (IM) increase the risk for the development of gastric cancer (GC) as they represent a field for development of dysplasia and intestinal-type gastric adenocarcinoma. METHODS: We have investigated the expression of two dysplasia markers, CEACAM5 and TROP2, in human antral IM and gastric tumors to assess their potential as molecular markers. RESULTS: In the normal antral mucosa, weak CEACAM5 and TROP2 expression was only observed in the foveolar epithelium, while inflamed antrum exhibited increased expression of both markers. Complete IM exhibited weak CEACAM5 expression at the apical surface, but no basolateral TROP2 expression. On the other hand, incomplete IM demonstrated high levels of both CEACAM5 and TROP2 expression. Notably, incomplete IM with dysplastic morphology (dysplastic incomplete IM) exhibited higher levels of CEACAM5 and TROP2 expression compared to incomplete IM without dysplastic features (simple incomplete IM). In addition, dysplastic incomplete IM showed diminished SOX2 and elevated CDX2 expression compared to simple incomplete IM. CEACAM5 and TROP2 positivity in incomplete IM was similar to that of gastric adenomas and GC. Significant association was found between CEACAM5 and TROP2 positivity and histology of GC. CONCLUSIONS: These findings support the concept that incomplete IM is more likely associated with GC development. Overall, our study provides evidence of the heterogeneity of gastric IM and the distinct expression profiles of CEACAM5 and TROP2 in dysplastic incomplete IM. Our findings support the potential use of CEACAM5 and TROP2 as molecular markers for identifying individuals with a higher risk of GC development in the context of incomplete IM.

Partially covered versus uncovered pyloro-duodenal stents for unresectable malignant gastric outlet obstruction: Randomized controlled study.

OBJECTIVES: The aim of the current study was to compare the efficacy of partially covered duodenal stent (PCDS) vs. uncovered duodenal stent (UCDS) in patients suffering from unresectable primary malignant gastric outlet obstruction (GOO). METHODS: This was a prospective international randomized controlled study conducted in 10 high-volume institutions. Consecutive patients suffering from malignant GOO were recruited. The primary outcome measurement was the reintervention rate. Secondary outcomes included technical and clinical success, 30-day adverse events, 30-day mortality, causes of stent dysfunction, and the duration of stent patency. RESULTS: Between March 2017 and October 2020, 115 patients (59 PCDS, 56 UCDS) were recruited. The 1-year reintervention was not significantly different (PCDS vs. UDCS = 12/59, 20.3% vs. 14/56, 25%, P = 0.84). There was a trend to fewer patients with tumor ingrowth in the PCDS group (6/59 [10.2%]) vs. 13/56 [23.2%], P = 0.07). There were no significant differences in the technical success (100% vs. 100%, P = 1), clinical success (91.5% vs. 98.2%, P = 0.21), procedural time (21.5 [interquartile range [IQR] 17-30] vs. 20.0 [IQR 15-34.75], P = 0.62), hospital stay (4 [IQR 3-12] vs. 5 [IQR 3-8] days, P = 0.81), 30-day adverse events (18.6% vs. 14.3%, P = 0.62), or 30-day mortality (6.8% vs. 5.2%, P = 1.00). CONCLUSION: The use of PCDS was associated with a lower risk of tumor ingrowth but did not improve on reintervention rates or stent patency. Both kinds of stents could be used in this group of patients.

Real-World Validation of a Computer-Aided Diagnosis System for Prediction of Polyp Histology in Colonoscopy: A Prospective Multicenter Study.

INTRODUCTION: Computer-aided diagnosis (CADx) of polyp histology could support endoscopists in clinical decision-making. However, this has not been validated in a real-world setting. METHODS: We performed a prospective, multicenter study comparing CADx and endoscopist predictions of polyp histology in real-time colonoscopy. Optical diagnosis based on visual inspection of polyps was made by experienced endoscopists. After this, the automated output from the CADx support tool was recorded. All imaged polyps were resected for histological assessment. Primary outcome was difference in diagnostic performance between CADx and endoscopist prediction of polyp histology. Subgroup analysis was performed for polyp size, bowel preparation, difficulty of location of the polyps, and endoscopist experience. RESULTS: A total of 661 eligible polyps were resected in 320 patients aged ≥40 years between March 2021 and July 2022. CADx had an overall accuracy of 71.6% (95% confidence interval [CI] 68.0-75.0), compared with 75.2% (95% CI 71.7-78.4) for endoscopists ( P = 0.023). The sensitivity of CADx for neoplastic polyps was 61.8% (95% CI 56.9-66.5), compared with 70.3% (95% CI 65.7-74.7) for endoscopists ( P < 0.001). The interobserver agreement between CADx and endoscopist predictions of polyp histology was moderate (83.1% agreement, κ 0.661). When there was concordance between CADx and endoscopist predictions, the accuracy increased to 78.1%. DISCUSSION: The overall diagnostic accuracy and sensitivity for neoplastic polyps was higher in experienced endoscopists compared with CADx predictions, with moderate interobserver agreement. Concordance in predictions increased this diagnostic accuracy. Further research is required to improve the performance of CADx and to establish its role in clinical practice.

Motorized spiral enteroscopy versus double-balloon enteroscopy: a case-matched study.

BACKGROUND AND AIMS: Motorized spiral enteroscopy (MSE) has been postulated to ease the complexities of the standard-of-care double-balloon enteroscopy (DBE). However, there are no comparative studies between MSE and DBE. This study aimed to compare the therapeutic outcomes and safety between MSE and DBE. METHODS: In this case-matched study, patients were matched 1:2 (MSE/DBE) by age, sex, body mass index, and American Society of Anesthesiology scores. Thirty-one patients who underwent MSE were compared with 62 patients who underwent DBE from 2014 to 2022. Our primary outcomes were to compare the technical and diagnostic success rates between DBE and MSE. Our secondary outcomes were to compare the therapeutic success and adverse event rates. RESULTS: The main indications for enteroscopy were suspected GI bleeding and positive radiologic findings. Prior abdominal surgery was reported in 35.5% and 22.6% of DBE and MSE patients, respectively. Most were antegrade enteroscopy (71%). We found no significant difference in the technical success (DBE 98.4% vs MSE 96.8%, P = .62), diagnostic success (DBE 66.1% vs MSE 54.8%, P = .25), and therapeutic success rates (DBE 62.8% vs MSE 52.9%, P = .62) between the groups. Adverse events occurred in 1 DBE and 11 MSE patients. Most were minor (n = 10, 25.6%). Two patients (5.1%) in the MSE group sustained deep lacerations in the proximal esophagus requiring hospitalization. One developed ileal perforation after MSE needing surgical repair. CONCLUSIONS: In patients requiring enteroscopy, the diagnostic and therapeutic performance of MSE is similar to DBE. An increased frequency of adverse events was observed with MSE. There are some restrictions in the indication because of the design of MSE.

Global prospective case series of ERCPs using a single-use duodenoscope.

BACKGROUND: The first commercialized single-use duodenoscope was cleared by the US Food and Drug Administration in December 2019. Data regarding endoscopic retrograde cholangiopancreatography (ERCP) using a single-use duodenoscope are needed on a broader range of cases conducted by endoscopists with varying levels of experience in a wide range of geographic areas. METHODS: 61 endoscopists at 22 academic centers in 11 countries performed ERCP procedures in adult patients aged ≥ 18. Outcomes included ERCP completion for the intended indication, rate of crossover to a reusable endoscope, device performance ratings, and serious adverse events (SAEs). RESULTS: Among 551 patients, 236 (42.8 %) were aged > 65, 281 (51.0 %) were men, and 256 (46.5 %) had their procedure as an inpatient. ERCPs included 196 (35.6 %) with American Society for Gastrointestinal Endoscopy complexity of grades 3-4. A total of 529 ERCPs (96.0 %) were completed: 503 (91.3 %) using only the single-use duodenoscope, and 26 (4.7 %) with crossover to a reusable endoscope. There were 22 ERCPs (4.0 %) that were not completed, of which 11 (2.0 %) included a crossover and 11 (2.0 %) were aborted cases (no crossover). Median ERCP completion time was 24.0 minutes. Median overall satisfaction with the single-use duodenoscope was 8.0 (scale of 1 to 10 [best]). SAEs were reported in 43 patients (7.8 %), including 17 (3.1 %) who developed post-ERCP pancreatitis. CONCLUSIONS: In academic medical centers over a wide geographic distribution, endoscopists with varying levels of experience using the first marketed single-use duodenoscope had good ERCP procedural success and reported high performance ratings for this device.

Severity of gastric intestinal metaplasia predicts the risk of gastric cancer: a prospective multicentre cohort study (GCEP).

OBJECTIVE: To investigate the incidence of gastric cancer (GC) attributed to gastric intestinal metaplasia (IM), and validate the Operative Link on Gastric Intestinal Metaplasia (OLGIM) for targeted endoscopic surveillance in regions with low-intermediate incidence of GC. METHODS: A prospective, longitudinal and multicentre study was carried out in Singapore. The study participants comprised 2980 patients undergoing screening gastroscopy with standardised gastric mucosal sampling, from January 2004 and December 2010, with scheduled surveillance endoscopies at year 3 and 5. Participants were also matched against the National Registry of Diseases Office for missed diagnoses of early gastric neoplasia (EGN). RESULTS: There were 21 participants diagnosed with EGN. IM was a significant risk factor for EGN (adjusted-HR 5.36; 95% CI 1.51 to 19.0; p<0.01). The age-adjusted EGN incidence rates for patients with and without IM were 133.9 and 12.5 per 100 000 person-years. Participants with OLGIM stages III-IV were at greatest risk (adjusted-HR 20.7; 95% CI 5.04 to 85.6; p<0.01). More than half of the EGNs (n=4/7) attributed to baseline OLGIM III-IV developed within 2 years (range: 12.7-44.8 months). Serum trefoil factor 3 distinguishes (Area Under the Receiver Operating Characteristics 0.749) patients with OLGIM III-IV if they are negative for H. pylori. Participants with OLGIM II were also at significant risk of EGN (adjusted-HR 7.34; 95% CI 1.60 to 33.7; p=0.02). A significant smoking history further increases the risk of EGN among patients with OLGIM stages II-IV. CONCLUSIONS: We suggest a risk-stratified approach and recommend that high-risk patients (OLGIM III-IV) have endoscopic surveillance in 2 years, intermediate-risk patients (OLGIM II) in 5 years.

Consensus guidelines on the role of cholangioscopy to diagnose indeterminate biliary stricture.

BACKGROUND: Indeterminate strictures pose a therapeutic dilemma. In recent years, cholangioscopy has evolved and the availability of cholangioscopy has increased. However, the position of cholangioscopy in the diagnostic algorithm to diagnose malignancy have not been well established. We aim to develop a consensus statement regarding the clinical role of cholangioscopy in the diagnosis of indeterminate biliary strictures. METHODS: The international experts reviewed the evidence and modified the statements using a three-step modified Delphi method. Each statement achieves consensus when it has at least 80% agreement. RESULTS: Nine final statements were formulated. An indeterminate biliary stricture is defined as that of uncertain etiology under imaging or tissue diagnosis. When available, cholangioscopic assessment and guided biopsy during the first round of ERCP may reduce the need to perform multiple procedures. Cholangioscopy are helpful in diagnosing malignant biliary strictures by both direct visualization and targeted biopsy. The absence of disease progression for at least 6 months is supportive of non-malignant etiology. Direct per-oral cholangioscopy provides the largest accessory channel, better image definition, with image enhancement but is technically demanding. Image enhancement during cholangioscopy may increase the diagnostic sensitivity of visual impression of malignant biliary strictures. Cholangioscopic imaging characteristics including tumor vessels, papillary projection, nodular or polypoid mass, and infiltrative lesions are highly suggestive for neoplastic/malignant biliary disease. The risk of cholangioscopy related cholangitis is higher than in standard ERCP, necessitating prophylactic antibiotics and ensuring adequate biliary drainage. Per-oral cholangioscopy may not be the modality of choice in the evaluation of distal biliary strictures due to inherent technical difficulties. CONCLUSION: Evidence supports that cholangioscopy has an adjunct role to abdominal imaging and ERCP tissue acquisition in order to evaluate and diagnose indeterminate biliary strictures.

The impact of the coronavirus disease 2019 pandemic on gastroenterologists in Southeast Asia: A mixed-methods study.

BACKGROUND AND AIM: The coronavirus disease 2019 pandemic has impacted gastroenterology practices worldwide; however, its protracted effects within Southeast Asia were unknown. The primary aim of the study was to determine the impact of the pandemic on clinical demands including burnout among gastroenterologists within the region. The secondary aim was to identify risk factors for burnout and determine regional stressors. METHODS: This was a mixed-methods study. Gastroenterologists were surveyed electronically between September 1 and December 7, 2020, via gastroenterology and endoscopy societies of Brunei, Indonesia, Malaysia, Philippines, Singapore, and Thailand. Quantitative and qualitative data were collected. The 22-item Maslach Burnout Inventory-Human Services Survey (MBI-HSS) was used to detect burnout. Quantitative data were non-parametric; non-parametric methods were used for statistical comparisons. Logistic regression was used to determine risk factors for burnout. Content analysis method was used to analyze qualitative data. Ethical approval was obtained. RESULTS: A total of 73.0% reported that they were still significantly affected by the pandemic. Of these, 40.5% reported increased workload and 59.5% decreased workload. Statistically significant differences in weekly working hours, endoscopy, and inpatient volumes were present. No differences were observed in outpatient volumes, likely because of telemedicine. Burnout was common; however, 50.1% of gastroenterologists were unaware of or did not have access to mental health support. This, as well as depression, being a trainee, and public sector work, increased burnout risk significantly. CONCLUSION: The effects of the pandemic are multifaceted, and burnout is common among Southeast Asian gastroenterologists. Safeguards for mental health are suboptimal, and improvements are urgently needed.

DNA damage signalling as an anti-cancer barrier in gastric intestinal metaplasia.

OBJECTIVE: Intestinal metaplasia (IM) is a premalignant stage that poses a greater risk for subsequent gastric cancer (GC). However, factors regulating IM to GC progression remain unclear. Previously, activated DNA damage response (DDR) signalling factors were shown to engage tumour-suppressive networks in premalignant lesions. Here, we interrogate the relationship of DDR signalling to mutational accumulation in IM lesions. DESIGN: IM biopsies were procured from the gastric cancer epidemiology programme, an endoscopic surveillance programme where biopsies have been subjected to (epi)genomic characterisation. IM samples were classified as genome-stable or genome-unstable based on their mutational burden/somatic copy-number alteration (CNA) profiles. Samples were probed for DDR signalling and cell proliferation, using the markers γH2AX and MCM2, respectively. The expression of the gastric stem cell marker, CD44v9, was also assessed. Tissue microarrays representing the GC progression spectrum were included. RESULTS: MCM2-positivity increased during GC progression, while γH2AX-positivity showed modest increase from normal to gastritis and IM stages, with further increase in GC. γH2AX levels correlated with the extent of chronic inflammation. Interestingly, genome-stable IM lesions had higher γH2AX levels underscoring a protective anti-cancer role for DDR signalling. In contrast, genome-unstable IM lesions with higher mutational burden/CNAs had lower γH2AX levels, elevated CD44v9 expression and modest promoter hypermethylation of DNA repair genes WRN, MLH1 and RAD52. CONCLUSIONS: Our data suggest that IM lesions with active DDR will likely experience a longer latency at the premalignant state until additional hits that override DDR signalling clonally expand and promote progression. These observations provide insights on the factors governing IM progression.

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.

International consensus statements for endoscopic management of distal biliary stricture.

Distal biliary strictures (DBS) are common and may be caused by both malignant and benign pathologies. While endoscopic procedures play a major role in their management, a comprehensive review of the subject is still lacking. Our consensus statements were formulated by a group of expert Asian pancreatico-biliary interventional endoscopists, following a proposal from the Digestive Endoscopy Society of Taiwan, the Thai Association for Gastrointestinal Endoscopy, and the Tokyo Conference of Asian Pancreato-biliary Interventional Endoscopy. Based on a literature review utilizing Medline, Cochrane library, and Embase databases, a total of 19 consensus statements on DBS were made on diagnosis, endoscopic drainage, benign biliary stricture, malignant biliary stricture, and management of recurrent biliary obstruction and other complications. Our consensus statements provide comprehensive guidance for the endoscopic management of DBS.

Diaphragmatic Breathing Reduces Belching and Proton Pump Inhibitor Refractory Gastroesophageal Reflux Symptoms.

BACKGROUND & AIMS: In patients with gastroesophageal reflux disease (GERD) and excessive belching, most belches are supragastric, and can induce reflux episodes and worsen GERD. Supragastric belching (SGB) might be reduced with diaphragmatic breathing exercises. We investigated whether diaphragmatic breathing therapy is effective in reducing belching and proton pump inhibitor (PPI)-refractory gastroesophageal reflux symptoms. METHODS: We performed a prospective study of 36 consecutive patients with GERD refractory to PPI therapy and a belching visual analogue scale (VAS) score of 6 or more, seen at a gastroenterology clinic at a tertiary hospital in Singapore from April 2015 through October 2016. Patients underwent high-resolution manometry and 24-hour pH-impedance studies while they were off PPIs. Fifteen patients were placed on a standardized diaphragmatic breathing exercise protocol (treatment group) and completed questionnaires at baseline, after diaphragmatic breathing therapy, and 4 months after the therapy ended. Twenty-one patients were placed on a waitlist (control subjects), completed the same questionnaires with an additional questionnaire after their waitlist period, and eventually received diaphragmatic breathing therapy. The primary outcome was reduction in belching VAS by 50% or more after treatment. Secondary outcomes included GERD symptoms (evaluated using the reflux disease questionnaire) and quality of life (QoL) scores, determined from the Reflux-Qual Short Form and EuroQoL-VAS. RESULTS: Nine of the 15 patients in the treatment group (60%) and none of the 21 control subjects achieved the primary outcome (P < .001). In the treatment group, the mean belching VAS score decreased from 7.1 ± 1.5 at baseline to 3.5 ± 2.0 after diaphragmatic breathing therapy; in the control group, the mean VAS score was 7.6 ± 1.1 at baseline and 7.4 ± 1.3 after the waitlist period. Eighty percent of patients in the treatment group significantly reduced belching frequency compared with 19% in control subjects (P = .001). Treatment significantly reduced symptoms of GERD (the mean reflux disease questionnaire score decreased by 12.2 in the treatment group and 3.1 in the control group; P = .01). The treatment significantly increased QoL scores (the mean Reflux-Qual Short Form score increased by 15.4 in the treatment group and 5.2 in the control group; P = .04) and mean EuroQoL-VAS scores (15.7 increase in treatment group and 2.4 decrease in the control group). These changes were sustained at 4 months after treatment. In the end, 20 of the 36 patients who received diaphragmatic breathing therapy (55.6%), all with excessive SGB, achieved the primary outcome. CONCLUSIONS: In a prospective study, we found a standardized protocol for diaphragmatic breathing to reduce belching and PPI-refractory gastroesophageal reflux symptoms, and increase QoL in patients with PPI-refractory GERD with belching-especially those with excessive SGB.

Role of fluorescence in situ hybridization in diagnosing cholangiocarcinoma in indeterminate biliary strictures.

BACKGROUND AND AIM: Brush cytology, the conventional method to diagnose cholangiocarcinoma, has been plagued by low diagnostic sensitivity and false-negative results. This paper aims to study the clinical utility of fluorescence in situ hybridization (FISH) in enhancing identification of malignant biliary strictures. METHODS: Brush cytologic specimens collected from endoscopic retrograde cholangiopancreatography for biliary strictures in a tertiary hospital in Singapore from March 2013 to July 2015 were examined by FISH technique using UroVysion probe set in this study. RESULTS: Thirty patients were chosen with five patients having multiple FISH performed due to indeterminate results. The diagnoses for biliary strictures were 13 (43.3%) cholangiocarcinomas, seven (23.3%) pancreatic cancers, seven (23.3%) benign biliary strictures, and three (10%) primary sclerosing cholangitis. Conventional brush cytology had sensitivity of 53.8% with specificity of 82.4%. FISH had sensitivity of 30.8% with specificity of 100%. When FISH results were interpreted in cases with negative or atypical brush cytology, two patients had positive FISH results and cholangiocarcinomas. Based on this pilot study, FISH increased sensitivity of brush cytology in detection of cholangiocarcinoma from 53.8% to 69.2% while preserving specificity of 82.4%. CONCLUSION: Compared with conventional cytology with low sensitivity, FISH may help to increase sensitivity on top of brush cytology while maintaining high specificity.

WEO position statement on hygiene in digestive endoscopy: Focus on endoscopy units in Asia and the Middle East.

The aim of this position statement is to reinforce the key points of hygiene in digestive endoscopy. The present article details the minimum hygiene requirements for reprocessing of endoscopes and endoscopic devices, regardless of the reprocessing method (automated washer-disinfector or manual cleaning) and the endoscopy setting (endoscopy suite, operating room, elective or emergency procedures). These minimum requirements are mandatory for patient safety. Both advanced diagnostic and therapeutic endoscopies should be carried out in an environment that is safe for patients and staff. Particular attention is given to contaminants. Procedural errors in decontamination, defective equipment, and failure to follow disinfection guidelines are major factors contributing to transmission of infection during endoscopy. Other important risk factors include inadequate cleaning, use of older endoscopes with surface and working channel irregularities, and contamination of water bottles or irrigating solutions. Infections by multidrug-resistant organisms have become an increasing problem in health-care systems worldwide. Since 2010, outbreaks of multidrug-resistant bacteria associated with endoscopic retrograde cholangiopancreatography have been reported from the USA, France, Germany, and The Netherlands. In many endoscopy units in Asia and the Middle East, reprocessing procedures have lagged behind those of Western countries for cultural reasons or lack of financial resources. This inconsistency in standards is now being addressed, and the World Endoscopy Organization has prepared this position statement to highlight key points for quality assurance in any endoscopy unit in any country.

Asian consensus statements on endoscopic management of walled-off necrosis. Part 2: Endoscopic management.

Walled-off necrosis (WON) is a new term for encapsulated necrotic tissue after severe acute pancreatitis. Various terminologies such as pseudocyst, necroma, pancreatic abscess, and infected necrosis were previously used in the literature, resulting in confusion. The current and past terminologies must be reconciled to meaningfully interpret past data. Recently, endoscopic necrosectomy was introduced as a treatment option and is now preferred over surgical necrosectomy when the expertise is available. However, high-quality evidence is still lacking, and there is no standard management strategy for WON. The consensus meeting aimed to clarify the diagnostic criteria for WON and the role of endoscopic interventions in its management. In the Consensus Conference, 27 experts from eight Asian countries took an active role and examined key clinical aspects of WON diagnosis and endoscopic management. Statements were crafted based on literature review and expert opinion, employing the modified Delphi method. All statements were substantiated by the level of evidence and the strength of the recommendation. We created 27 consensus statements for WON diagnosis and management, including details of endoscopic procedures. When there was not enough solid evidence to support the statements, this was clearly acknowledged to facilitate future research. Proposed management strategies were formulated and are illustrated using flow charts. These recommendations, which are based on the best current scientific evidence and expert opinion, will be useful for guiding endoscopic management of WON. Part 2 of this statement focused on the endoscopic management of WON.

Asian consensus statements on endoscopic management of walled-off necrosis Part 1: Epidemiology, diagnosis, and treatment.

Walled-off necrosis (WON) is a relatively new term for encapsulated necrotic tissue after severe acute pancreatitis. Various terminologies such as pseudocyst, necroma, pancreatic abscess, and infected necrosis were previously used in the literature, resulting in confusion. The current and past terminologies must be reconciled to meaningfully interpret past data. Recently, endoscopic necrosectomy was introduced as a treatment option and is now preferred over surgical necrosectomy when the expertise is available. However, high-quality evidence is still lacking, and there is no standard management strategy for WON. The consensus meeting aimed to clarify the diagnostic criteria for WON and the role of endoscopic interventions in its management. In the Consensus Conference, 27 experts from eight Asian countries took an active role and examined key clinical aspects of WON diagnosis and endoscopic management. Statements were crafted based on literature review and expert opinion, employing the modified Delphi method. All statements were substantiated by the level of evidence and the strength of the recommendation. We created 27 consensus statements for WON diagnosis and management, including details of endoscopic procedures. When there was not enough solid evidence to support the statements, this was clearly acknowledged to facilitate future research. Proposed management strategies were formulated and are illustrated using flow charts. These recommendations, which are based on the best current scientific evidence and expert opinion, will be useful for guiding endoscopic management of WON. Part 1 of this statement focused on the epidemiology, diagnosis, and timing of intervention.