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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.In this case-matched study, patients were matched 1:2 (MSE/DBE) by age, sex, body mass index (BMI), and American Society of Anesthesiology (ASA) 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 complication rates.The main indications of enteroscopy were suspected GI bleeding and positive radiological 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=0.62), diagnostic success (DBE 66.1% vs. MSE 54.8%, p=0.25) and the therapeutic success rates (DBE 62.8% vs. MSE 52.9%, p=0.62) between the groups. Complications occurred in one 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.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 restriction in the indication because of the design of MSE.

Gastric cancer (GC) has a good prognosis, if detected at an early stage. The intestinal subtype of GC follows a stepwise progression to carcinoma, which is treatable with early detection and intervention using high-quality endoscopy. Premalignant lesions and gastric epithelial polyps are commonly encountered in clinical practice. Surveillance of patients with premalignant gastric lesions may aid in early diagnosis of GC, and thus improve chances of survival. An expert professional workgroup was formed to summarise the current evidence and provide recommendations on the management of patients with gastric premalignant lesions in Singapore. Twenty-five recommendations were made to address screening and surveillance, strategies for detection and management of gastric premalignant lesions, management of gastric epithelial polyps, and pathological reporting of gastric premalignant lesions. Keywords: Early gastric neoplasia, endoscopic surveillance, gastric cancer, intestinal metaplasia, polyp

Intestinal metaplasia (IM) is a pre-malignant condition of the gastric mucosa associated with increased gastric cancer (GC) risk. We analyzed 1256 gastric samples (1152 IMs) from 692 subjects through a prospective 10-year study. We identified 26 IM driver genes in diverse pathways including chromatin regulation (ARID1A) and intestinal homeostasis (SOX9), largely occurring as small clonal events. Analysis of clonal dynamics between and within subjects, and also longitudinally across time, revealed that IM clones are likely transient but increase in size upon progression to dysplasia, with eventual transmission of somatic events to paired GCs. Single-cell and spatial profiling highlighted changes in tissue ecology and lineage heterogeneity in IM, including an intestinal stem-cell dominant cellular compartment linked to early malignancy. Expanded transcriptome profiling revealed expression-based molecular subtypes of IM, including a body-resident “pseudoantralized” subtype associated with incomplete histology, antral/intestinal cell types,ARID1Amutations, inflammation, and microbial communities normally associated with the healthy oral tract. We demonstrate that combined clinical- genomic models outperform clinical-only models in predicting IMs likely to progress. Our results raise opportunities for GC precision prevention and interception by highlighting strategies for accurately identifying IM patients at high GC risk and a role for microbial dysbiosis in IM progression.

Colonoscopy with endoscopic resection of detected colonic adenomas interrupts the adenoma-carcinoma sequence and reduces the incidence of colorectal cancer and cancer-related mortality. In the past decade, there have been significant developments in instruments and techniques for endoscopic polypectomy. Guidelines have been formulated by various professional bodies in Europe, Japan and the United States, but some of the recommendations differ between the various bodies. An expert professional workgroup under the auspices of the Academy of Medicine, Singapore, was set up to provide guidance on the endoscopic management of colonic polyps in Singapore. A total of 23 recommendations addressed the following issues: accurate description and diagnostic evaluation of detected polyps; techniques to reduce the risk of post-polypectomy bleeding and delayed perforation; the role of specific endoscopic resection techniques; the histopathological criteria for defining endoscopic cure; and the role of surveillance colonoscopy following curative resection.

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.

EUS-guided cystogastrostomy is a well-established advanced endoscopic technique with a steep-learning curve which necessitates an ex-vivo simulator that would allow for adequate training. The aim of this study is to evaluate the feasibility of the model in allowing training for EUS-guided cystogastrostomy using lumen-apposing metal stent (LAMS).The model was created by ROEYA Training Center, Egypt, using native porcine tissue to create fluid collections simulating both cystic and solid lesions. It was designed and tested in advance while the hydrogel was added on-site. The simulator was evaluated prospectively in five training sessions involving 17 international experts. The task was to successfully deploy the LAMS to drain the created cyst. After using the simulator, the experts were asked to fill a questionnaire to assess their experience. The primary endpoint was overall satisfaction with the model as a training tool.All of the experts were satisfied with the model as a tool to train endoscopists for the technique. 76.5% (n = 11) of the experts thought the model to be moderately realistic. Proper visualization was reported by 94.1% of the experts. All experts believed the lesions to be either slightly like or very similar to real lesions. The model was graded "easy" in difficulty by 11 of the experts.In all parameters assessed, the experts thought the model to be a useful tool for future training. This preliminary study suggests that the aforementioned simulator can be used to train endoscopists on using LAMS in a risk-free environment.

Aberrant DNA methylation accumulates in non-malignant gastric mucosa after exposure to environmental pathogens such as H. pylori (HP). To understand how environmental factors and DNA methylation interplay to influence primary gastric cancer (GC) risk, we performed an integrated analysis of clinical factors and DNA methylation data of gastric tissues from a longitudinally monitored cohort in Japan, with validation in a separate cohort from Singapore. The Japanese check-up cohort included 4,234 healthy subjects who underwent gastric mucosal biopsy. The median observation period was 4.2 years, and 77 subjects developed GC. GC incidence correlated with age, drinking, smoking, GC family history, and HP status in the multivariable Cox model. Next, we conducted comprehensive DNA methylation analysis using Infinium MethylationEPIC arrays on gastric tissues (n=164), including (1) mucosal biopsies from subjects who later developed GC (“future GC patients”), (2) mucosal biopsies from HP(+) subjects who did not later develop GC (“future non-GC subjects”), (3) mucosal biopsies from future non-GC HP(−) subjects (“control mucosae”), and (4) GCs and surrounding mucosae. Infinium data of gastric mucosae (n=137) collected in the GCEP cohort (Singapore) were also analyzed. DNA methylation of promoter region observed in GCs, accumulated not only in mucosae adjacent to GCs but also in the biopsy mucosae of future GC patients. Mucosae of future non-GC subjects were more methylated than control mucosae but less methylated than mucosae of future GC patients. Similar findings were observed in the GCEP cohort. DNA methylation levels were associated with clinical factors and histopathological alterations - however, in multivariable analyses, DNA methylation remained an independent GC risk factor. Methylation levels were predictive of not only higher GC risk but also a shorter period to GC incidence. We then focused on the associations between environmental factors and methylation. Heavy drinking and smoking were associated with the accumulation of DNA methylation only in HP(+) subjects. The increases in methylation over time in subjects who quit smoking were significantly attenuated compared to continuous smokers. These results suggest that pro-carcinogenic epigenetic alterations initiated by HP exposure are amplified by unfavorable but modifiable lifestyle choices. Furthermore, target genes methylated by each environmental factor may overlap in part; however, they were not necessarily methylated similarly, suggesting that the best markers for stratifying GC risk may differ for each subgroup classified by exposure to environmental factors. Indeed, candidate markers for stratifying GC risk overlapped among subgroups, whereas markers unique to each subgroup were also identified, highlighting the potential of integrating environmental, lifestyle, and epigenetic information to inform GC precision prevention. Citation Format: Genki Usui, Keisuke Matsusaka, Kie K. Huang, Feng Zhu, Tomohiro Shinozaki, Masaki Fukuyo, Bahityar Rahmutulla, Norikazu Yogi, Tomoka Okada, Motoaki Seki, Eiji Sakai, Kazutoshi Fujibayashi, Stephen K. Tsao, Christopher Khor, Tiing L. Ang, Hiroyuki Abe, Hisahiro Matsubara, Masashi Fukayama, Toshiaki Gunji, Nobuyuki Matsuhashi, Teppei Morikawa, Tetsuo Ushiku, Khay G. Yeoh, Patrick Tan, Atsushi Kaneda. Integrated environmental, lifestyle, and epigenetic risk prediction of primary gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 761.