Effects of 1-kestose on microbiome changes caused by vonoprazan: a randomized, double-blind, placebo-controlled pilot study.

BACKGROUND AND AIM: Potassium-competitive acid blockers more strongly suppress the gastric acid barrier than proton pump inhibitors and cause dysbiosis. However, preventive measures in this regard have not been established. We aimed to evaluate whether 1-kestose, a known prebiotic, was effective at alleviating dysbiosis caused by potassium-competitive acid blockers. METHODS: Patients scheduled to undergo endoscopic resection for superficial gastroduodenal tumors were enrolled and randomized 1:1 to receive either 1-kestose or placebo. All patients were started on potassium-competitive acid blocker (vonoprazan 20 mg/day) and took 1-kestose 10 g/day or placebo (maltose) 5 g/day for 8 weeks. The primary outcome was the effect of 1-kestose on potassium-competitive acid blocker-induced alterations in the microbiome. The fecal microbiome was analyzed before and after potassium-competitive acid blocker treatment via MiSeq (16S rRNA gene V3-V4 region). RESULTS: Forty patients were enrolled, and 16 in each group were analyzed. In the placebo group, the Simpson index, an alpha diversity, was significantly decreased and relative abundance of Streptococcus was significantly increased by 1.9-fold. In the kestose group, the Simpson index did not change significantly and relative abundance of Streptococcus increased 1.3-fold, but this was not a significant change. In both groups, no adverse events occurred, ulcers were well healed, and pretreatment and posttreatment short-chain fatty acid levels did not differ. CONCLUSIONS: The potassium-competitive acid blocker caused dysbiosis in the placebo group; this effect was prevented by 1-kestose. Thus, 1-kestose may be useful in dysbiosis treatment.

Gastric ectopic pancreas with a pseudocyst.

Ectopic pancreas (EP) is defined as pancreatic tissue that lacks anatomical or vascular connections to the normal pancreas. EP is generally asymptomatic and is detected incidentally during endoscopy. However, due to pseudocyst formation, inflammation, or malignant transformation, it may cause non-specific gastrointestinal symptoms, such as abdominal pain, abdominal discomfort, nausea, vomiting, and bleeding. Pseudocyst formation in EP may result from the retention of exocrine secretions in the absence of connections between the glandular epithelium and gastric lumen. We herein report a case of EP with a pseudocyst associated with epigastric pain. EP with a pseudocyst, although rare, needs to be considered in a differential diagnosis of cystic lesions of the stomach.

Factors Related to Delayed Adverse Events of Endoscopic Submucosal Dissection in the Duodenum.

INTRODUCTION: Endoscopic submucosal dissection for duodenal neoplasms (D-ESD) is considered a technically demanding procedure regarding the high risk of delayed adverse events. Data regarding optimal managements of ulcers after D-ESD are lacking. METHODS: A retrospective analysis was performed on consecutive 145 cases of D-ESD for superficial nonampullary duodenal epithelial tumors at a single referral center. Factors related to delayed adverse events and the healing process of ulcers after D-ESD were analyzed. RESULTS: Complete ulcer suture after D-ESD was performed in 128 cases (88%). Two delayed perforation occurred among cases with incomplete suture. Delayed bleeding occurred in 8 cases (6%) within 3 weeks. The ulcer closure rate at second-look endoscopy (SLE) was significantly low among cases with delayed bleeding (12.5% vs. 75%, p = 0.001). The bleeding rate before SLE was significantly high among patients who did not have complete ulcer closure after D-ESD (0.8% vs. 12%, p = 0.036). The ratio of lesions located in the second oral-Vater was significantly low among ulcers re-opened at SLE (38% vs. 14%, p = 0.044). Proton-pump inhibitors (PPIs) were administered for a median of 7 weeks (range 1-8 weeks). At 3 weeks, active ulcer stages were observed in a few cases, and healing or scarring was observed in most cases. CONCLUSIONS: Complete ulcer suture was related to decreased risk of delayed adverse events after D-ESD. From the bleeding period and healing process of D-ESD ulcers, the minimum required length of PPI may be 3 weeks after D-ESD.

Diagnostic Performance of Endocytoscopy for Esophageal Eosinophilia.

INTRODUCTION: Eosinophils in the esophageal epithelium are unevenly distributed in eosinophilic esophagitis (EoE). Esophageal eosinophilia (EE) may be observable by endocytoscopy (EC). This study aimed to evaluate the diagnostic performance of EC for the diagnosis of EE. METHODS: A total of 33 EoE patients underwent EC with methylene blue staining from March 2020 to April 2021. A total of 194 EC images with corresponding biopsies were obtained. Three findings of EC, increased squamous cells (item I), increased inflammatory cells (item II), and cells with bilobed nuclei (item III), were established. These findings were reviewed by two endoscopists to diagnose EE. Another four endoscopists reviewed the images for interobserver agreement. RESULTS: When all three items were met by EC, the sensitivity and the accuracy for the diagnosis of EE were 88% and 76%, respectively. The integrated diagnostic odds ratios (ORs) for the diagnosis of EE of the four endoscopists were significant (OR: 3.98, 95% CI: 2.94-5.40, p < 0.001). The results were similar when only item III was met. Interobserver agreement was good for item III to diagnose EE (kappa value = 0.653). DISCUSSION/CONCLUSION: The diagnostic performance of EC for EE is acceptable and has good interobserver agreement. It may be useful for targeted biopsy in EoE patients.

Scoring system for predicting the prognosis of elderly gastric cancer patients after endoscopic submucosal dissection.

OBJECTIVES: Comprehensive assessments of the long-term outcomes of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) in the elderly are unavailable. We aimed to create a scoring system to predict the long-term prognosis after ESD for EGC among patients aged ≥75 years. METHODS: We conducted retrospective studies of two cohorts: a single-center cohort (2006-2011) for developing the scoring system, and a multicenter cohort for validating the developed system (2012-2016). In the development cohort, factors related to death after ESD were identified using multivariable Cox regression analysis, and a predictive scoring system was developed. In the validation cohort, the scoring system was validated in 295 patients. RESULTS: In the development cohort, Charlson comorbidity index (CCI) ≥3 (hazard ratio [HR] 3.017), high psoas muscle index (PMI) (HR 2.206), and age ≥80 years (HR 1.978) were significantly related to overall survival after ESD. Therefore, high CCI, low PMI, and age ≥80 years were assigned 1 point each. The patients were categorized into low (≤1 point) and high (≥2 points) score groups based on their total scores. In the validation cohort, 184 and 111 patients were assigned to the low- and high-score groups, respectively. In comparisons based on Kaplan-Meier curves, the 5-year survival rate was 91.5% in the low-score group and 57.8% in the high-score group (log-rank test; P < 0.001). CONCLUSION: Our scoring system including high CCI, low PMI, and age ≥80 years could stratify the long-term prognosis of elderly patients aged ≥75 years after ESD for EGC.

Endoscopic submucosal dissection using an ultrathin endoscope for esophageal squamous cell carcinoma with anastomotic stenosis.

In endoscopic submucosal dissection (ESD) for esophageal squamous cell carcinoma (ESCC) beyond the stricture, balloon dilation is commonly performed until a conventional endoscope with a distal attachment may pass through. We herein present a case of ESCC with anastomotic stenosis after pharyngolaryngoesophagectomy that underwent ESD using an ultrathin endoscope. The ultrathin endoscope does not require balloon dilation, and the transparent hood mounted at the distal end of the ultrathin endoscope allows for a more rapid approach to the submucosa than a conventional endoscope. Therefore, ESD with an ultrathin endoscope is a useful endoscopic treatment option for ESCC with stricture.

Endoscopic submucosal dissection using a novel thin-therapeutic endoscope for superficial esophageal squamous cell carcinoma with severe stricture at the pharyngoesophageal junction.

When performing endoscopic submucosal dissection (ESD) beyond stenoses, there have only been two choices: balloon dilation until a conventional therapeutic endoscope passes through or the use of an ultrathin endoscope. However, balloon dilation has a risk of perforation and an ultrathin endoscope limits the devices that may be used. The novel thin-therapeutic endoscope has an outer diameter of 7.9 mm and instrument channel diameter of 3.2 mm; therefore, there are no restrictions on the ESD device that may be used, and the procedure may be performed in the same manner as regular ESD. We herein report a case in which the thin-therapeutic endoscope was useful for esophageal ESD beyond a stenosis.

Suturing of a mucosal defect after gastric endoscopic submucosal dissection using a combination of an anchor pronged clip and conventional clips.

Suturing of a mucosal defect after gastric endoscopic submucosal dissection (ESD) reduces the incidence of adverse events and shortens hospitalization. However, post-ESD mucosal defects are circular, large, and with a thick mucosal layer, which are difficult to suture using conventional clips alone. The MANTIS Clip (Boston Scientific Japan, Tokyo, Japan) is a reopenable, rotatable through-the-scope clip designed for large defect closure. It uses anchor prongs to securely grasp wound edges. The initial use of the MANTIS Clip significantly reduces mucosal defects, which then allows for easy suturing with conventional clips. We herein report a case in which the MANTIS Clip was useful for suturing a mucosal defect after gastric ESD.

Novel endoscopic approaches using the endocytoscopy for the target biopsy in esophageal eosinophilia.

BACKGROUND AND AIMS: Multiple biopsies are recommended for the diagnosis of eosinophilic esophagitis (EoE) because inflammatory changes are frequently patchy. Reports on EoE using endocytoscopy (ECS) are limited. This present study aimed to assess if diagnostic yield improves by adding ECS on conventional white light imaging (WLI) in patients with esophageal eosinophilia (EE). METHODS: A total of 284 biopsy specimens from 71 patients with a known diagnosis of EE were enrolled and divided into the WLI group (156 specimens) or the ECS group (128 specimens). Four biopsies from 5 and 10 cm proximal to the esophagogastric junction were taken from each patient. In the ECS group, the biopsy was performed where bilobed nuclei were observed. The biopsy sensitivity for EE, eosinophil count of a single specimen and the biopsy sensitivity of each endoscopic finding were evaluated between both groups. RESULTS: The sensitivity of a single biopsy specimen was higher in the ECS group than that of the WLI group (62.5 vs. 41.7%, P < 0.001). In addition, the median eosinophil count in the ECS group was significantly higher [19 vs. 6.5/high-power field (HPF), P < 0.001]. For each endoscopic finding, ECS-based biopsy had higher sensitivity than that of WLI in the diagnosis of edema (33.1 vs. 11.3%, P = 0.007) and linear furrows (75.8 vs. 52%, P = 0.005). CONCLUSION: This study showed that adding ECS to WLI improved the biopsy sensitivity and eosinophil detection in patients with EE.

Changes in the gut microbiome in relation to the degree of gastric mucosal atrophy before and after Helicobacter pylori eradication.

OBJECTIVES: Helicobacter pylori infection causes atrophic gastritis, which affects the gut microbiome; the gastric acid concentration depends on the degree of atrophic gastritis. Helicobacter pylori eradication also affects gastric acidity. Here, we determined the differences in the post-eradication changes in the gut microbiome in relation to the progression of gastric atrophy. MATERIALS AND METHODS: Ten patients were included in the closed group and five in the open group, consisting of patients with non-progressive and progressive atrophy, respectively, diagnosed by endoscopy. The faecal microbiome was analysed and compared among three time-points: before eradication, 8 weeks after eradication, and 6 months after eradication. The microbiome was analysed by targeting 16S rRNA using Illumina Miseq. RESULTS: The relative abundance of 14 genera significantly differed between the closed and open groups before eradication, but only 12 and 6 genera presented a significant difference in the relative abundance at 8 weeks and 6 months after eradication, respectively. Of the 12 genera that differed between the closed and open groups before eradication, 8 genera, namely, Actinomyces, Aggregatibacter, Campylobacter, Granulicatella, Pyramidobacter, Streptococcus, Cardiobacterium, and Haemophilus, were oral-origin bacteria. Longitudinal changes showed that Haemophilus and Catenibacterium were consistently significantly more abundant in the open group than in the closed group during the follow-up period. CONCLUSION: The gut microbiome substantially differed depending on the progression of gastric atrophy, but this difference was decreased by eradication, especially the differences in the number of oral bacteria in the gut. Eradication therapy may improve dysbiosis that result from gastric atrophy.

Fecal microbiota transplantation in the treatment of irritable bowel syndrome: a single-center prospective study in Japan.

BACKGROUND: Fecal microbiota transplantation (FMT) is a potential treatment for irritable bowel syndrome (IBS), but its efficacy in Japanese IBS patients is unknown. This study aimed to evaluate the efficacy, side effects, and microbiome changes following FMT in Japanese IBS patients. METHODS: Seventeen Japanese patients with refractory IBS received FMT (4 donors) under colonoscopy. Responders were defined by an improvement in the IBS severity index (IBS-SI) of 50 points or more after 12 weeks. We evaluated the IBS-SI and Bristol Stool Form Scale (BSFS) and compared the diversity and microbiome before and 12 weeks after FMT. For the microbiome, we analyzed the V3-V4 region of the 16S rRNA gene. RESULTS: IBS-SI decreased an average of 115.58 points after 12 weeks, and 10 patients (58.8%) were considered responders. Eight patients with diarrhea (66.7%) and three patients with constipation (60.0%) showed improvement in the BSFS. Two patients complained of mild abdominal pain, but there were no cases with severe side-effects. α-diversity was increased only in the responder group (p = 0.017). Patients who closely paralleled the donor microbiome had a higher rate of IBS-SI improvement. The relative abundance of Neisseria and Akkermansia increased and Desulfovibrio and Delftia were decreased in the responder group after FMT. CONCLUSIONS: Following FMT, about 60% of Japanese patients with IBS showed improvement in both the IBS-SI and BSFS, without severe side effects. Increased α-diversity and similarity to the donor microbiome after FMT may be associated with better treatment effects. TRIAL REGISTRATION: This study was registered in the University Hospital Medical Information Network Clinical Trial Registration (UMIN000026363). Registered 31 May 2017, https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000026363 . The study was registered prospectively.

Artificial intelligence-based diagnosis of upper gastrointestinal subepithelial lesions on endoscopic ultrasonography images.

BACKGROUND: Endoscopic ultrasonography (EUS) is useful for the differential diagnosis of subepithelial lesions (SELs); however, not all of them are easy to distinguish. Gastrointestinal stromal tumors (GISTs) are the commonest SELs, are considered potentially malignant, and differentiating them from benign SELs is important. Artificial intelligence (AI) using deep learning has developed remarkably in the medical field. This study aimed to investigate the efficacy of an AI system for classifying SELs on EUS images. METHODS: EUS images of pathologically confirmed upper gastrointestinal SELs (GIST, leiomyoma, schwannoma, neuroendocrine tumor [NET], and ectopic pancreas) were collected from 12 hospitals. These images were divided into development and test datasets in the ratio of 4:1 using random sampling; the development dataset was divided into training and validation datasets. The same test dataset was diagnosed by two experts and two non-experts. RESULTS: A total of 16,110 images were collected from 631 cases for the development and test datasets. The accuracy of the AI system for the five-category classification (GIST, leiomyoma, schwannoma, NET, and ectopic pancreas) was 86.1%, which was significantly higher than that of all endoscopists. The sensitivity, specificity, and accuracy of the AI system for differentiating GISTs from non-GISTs were 98.8%, 67.6%, and 89.3%, respectively. Its sensitivity and accuracy were significantly higher than those of all the endoscopists. CONCLUSION: The AI system, classifying SELs, showed higher diagnostic performance than that of the experts and may assist in improving the diagnosis of SELs in clinical practice.

Comparison of Endoscopic Ultrasonography and Conventional Endoscopy for Prediction of Tumor Depth in Superficial Nonampullary Duodenal Epithelial Tumors.

BACKGROUND: The utility of endoscopic ultrasonography (EUS) in predicting tumor depth among superficial nonampullary duodenal epithelial tumors (SNADETs) is unclear. The aim was to compare EUS with conventional endoscopy (CE) for the evaluation of tumor invasion of SNADETs. METHODS: A retrospective analysis was performed on consecutive 174 lesions/169 patients with duodenal dysplasia or adenocarcinoma with invasion up to submucosa who underwent both CE and EUS before endoscopic (n = 133) or surgical (n = 41) treatment. Endoscopic staging by CE was performed based on the characteristic endoscopic criteria of submucosal invasion (irregular surface, submucosal tumor [SMT]-like marginal elevation, and fusion of converging folds). The diagnostic performance of each test was compared with the final histology. RESULTS: The sensitivity and accuracy of estimating the depth were higher for CE compared to that of EUS (99.4% vs. 89.4%, p < 0.01 and 97.7% vs. 87.9%, p < 0.01, respectively). Univariate analysis of endoscopic factors revealed that tumor diameter, red color, SMT-like appearance, and hypoechogenicity were factors related to advanced histology. Multivariate analysis revealed that the presence of SMT-like appearance based on CE was an independent factor to predict submucosal invasion (p = 0.025). Gross morphology of the combined type was associated to incorrect diagnosis of EUS (p = 0.007). Among 3 cases in which EUS overestimated the tumor depth, carcinoma extension in submucosal Brunner's gland or nontumorous submucosal cystic dilation was observed. CONCLUSION: EUS may not be necessary, and CE may be sufficient for determining the optimal therapeutic strategy for SNADETs.

Effects of steroid use for stenosis prevention after endoscopic submucosal dissection for cervical esophageal cancer.

BACKGROUND AND AIM: Esophageal stenosis is a serious complication after endoscopic submucosal dissection (ESD) for thoracic esophageal cancer (TEC), and steroid has been applied for stenosis prevention. However, the rate of stenosis and effect of steroid for ESD of cervical esophageal cancer (CEC) remain unknown. The aim was to clarify the rate and managements of post-ESD stenosis for CEC. METHODS: A total of 325 lesions with 272 patients who underwent ESD for esophageal cancers were enrolled and were divided to the CEC group (43 lesions) or the TEC group (282 lesions). Patient characteristics, clinicopathological features, procedure-related outcomes of esophageal ESD, stenosis rate and clinical outcome of steroid use cases were evaluated. RESULTS: More patients in the CEC group received preventive steroid treatment compared to the TEC group (37.2% vs 14.5%, P = 0.001). The rate of post-ESD stenosis tended to be higher in the CEC group (11.6%) than in the TEC group (6.7%). For cases of 3/4 ≤ of circumference, local injection with oral steroid had lower stenosis rate than local injection only in both groups (CEC 40% vs 100%, TEC 30.7% vs 56.3%). More sessions and longer duration of dilation were needed to release the stenosis in the CEC group (20 times vs. 5 times, P = 0.015; 196 days vs. 55 days, P = 0.043). CONCLUSION: The post-ESD stenosis rate of CEC tended to be higher than that of TEC. More intensive preventive measures for post-ESD stenosis may be needed for CEC than TEC.

Modified N score is helpful for identifying patients who need endoscopic intervention among those with black stools without hematemesis.

OBJECTIVES: Although black stools are one of the signs of upper gastrointestinal bleeding, not all patients without hematemesis need endoscopic intervention. There is no apparent indicator to select who needs treatment thus far. The aim of this study was to establish a novel score that predicts the need for endoscopic intervention in patients with black stools without hematemesis. METHODS: We retrospectively enrolled 721 consecutive patients with black stools without hematemesis who underwent emergency endoscopy from two facilities. In the development stage (from January 2016 to December 2018), risk factors that predict the need for endoscopic intervention were determined from the data of 422 patients by multivariate logistic regression analysis, and a novel scoring system, named the modified Nagoya University score (modified N score), was developed. In the validation stage (from January 2019 to September 2020), we evaluated the diagnostic value of the modified N score for 299 patients. RESULTS: Multivariate logistic regression analysis revealed four predictive factors for endoscopic intervention: syncope, the blood urea nitrogen (BUN) level, and the BUN/creatinine ratio as positive indicators and anticoagulant drug use as a negative indicator. In the validation stage, the area under the curve of the modified N score was 0.731, and the modified N score showed a sensitivity of 82.0% and a specificity of 58.8%. CONCLUSIONS: Our modified N score, which consists of only four factors, can identify patients who need endoscopic intervention among those with black stools without hematemesis.

Fecal incontinence and oral regurgitation during duodenal endoscopic submucosal dissection using the water pressure method.

OBJECTIVES: Endoscopic submucosal dissection (ESD) in the duodenum is challenging. The water pressure method (WP-ESD) has been developed with a decreased rate of perforation. However, details of perioperative adverse events of WP-ESD are unknown. The purpose of this study was to clarify the frequency and related factors of fecal incontinence and oral regurgitation during WP-ESD. METHODS: A chart-based retrospective analysis was performed on 43 patients who underwent duodenal WP-ESD. The saline volume given into the body was calculated in all cases. All adverse events during WP-ESD until 6 weeks were extracted, and factors related to intraoperative fecal incontinence or oral regurgitation were analyzed. The frequency of fecal incontinence and oral regurgitation was also compared to those of 83 conventional ESD cases. RESULTS: In WP-ESD, intraoperative fecal incontinence occurred in 12 (28%), oral regurgitation in six (14%), and aspiration pneumonia in one patient. For fecal incontinence, the infusion speed (saline volume divided by resection time) around 17 mL/min was a significant factor in multivariable analysis. For oral regurgitation, only tumor size was a significant factor in univariate analysis (P = 0.027). Significant difference was observed in the frequency of fecal incontinence between WP-ESD and conventional ESD (28% vs. 0%, P < 0.001), but no difference was observed in oral regurgitation or aspiration pneumonia. CONCLUSIONS: Intraoperative fecal incontinence is a unique adverse event of WP-ESD related to the infusion speed. WP-ESD did not pose a risk for oral regurgitation, but we should be aware of the risk in large tumor cases.

The impact of tube replacement timing during LCIG therapy on PEG-J associated adverse events: a retrospective multicenter observational study.

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) treatment, a unique drug delivery system for patients with advanced Parkinson's disease (PD), is covered by health insurance in Japan since September 2016. Various LCIG procedure/device-associated adverse events (AEs) have been reported; however, reports on their treatment have been limited. This is the first multicenter study to clarify the frequency and timing of device-related AEs. METHODS: Between September 2016 and December 2018, 104 patients introduced to the LCIG treatment for advanced PD in 11 hospitals were included. The patients' characteristics, AEs incidence, AEs time, and tube exchange time were investigated. RESULTS: The median follow-up period was 21.5 months. Minor AE cases were 29.4%, whereas major AE cases were 43.1%. Majority of major AEs (n = 55, 94.8%) were managed with endoscopic treatment, such as tube exchange. Few severe AEs required surgical treatment (n =3, 5.2%). The mean (range) exposure to percutaneous endoscopic gastrojejunostomy (PEG-J) was 14.7 (0-33) months. One year after the LCIG treatment introduction, 55 patients (54.0%) retained the original PEG-J tube. The mean PEG-J tube exchange time was 10.8 ± 7.0 months in all patients, 11.6 ± 4.7 and 10.5 ± 7.7 months in patients with scheduled exchange and who underwent exchange due to AEs, respectively. CONCLUSIONS: Some device-related AEs occurred during the LCIG treatment; however, only few were serious, most of which could be treated with simple procedures or tube replacement with endoscopy. Therefore, the LCIG treatment is feasible and safe and is a unique treatment option for PD, requiring endoscopists' understanding and cooperation.

Endocytoscopy Is Useful for the Diagnosis of Superficial Nonampullary Duodenal Epithelial Tumors.

INTRODUCTION: Endoscopic criteria for the diagnosis of superficial nonampullary duodenal epithelial tumors (SNADETs) are lacking. The aim of this study was to explore the usefulness of endocytoscopy (ECS) in the duodenum. METHODS: A total of 77 ECS images stained by methylene blue and 58 images with double staining of methylene blue and crystal violet were obtained from 20 patients. Images were classified into 3 grades based on nuclear and villi atypia: EC A, B, and C. Diagnostic performance of ECS classification to predict histology and interobserver agreement was evaluated. The performance was compared between staining methods and ×520 or ×936 zoom. RESULTS: With methylene blue staining, high rates of accuracy, sensitivity, specificity, and positive predictive value (PPV) over 90% were achieved for tumor and nontumor diagnosis as assessed by EC A versus EC B. High rates of accuracy, sensitivity, PPV, and negative predictive value over 90% were achieved for the differentiation between the diagnosis of the Vienna category 3 and 4/5 as assessed by EC B versus C. The accuracy rate of interpreting ECS images with ×936 zoom among 10 endoscopists was 82%, and the interobserver agreement rate was 0.803 (Kendall's coefficient of concordance). In the ×936 zoom group, methylene blue staining was significantly associated with higher accuracy rate (odds ratio 1.76 [1.06-2.92], p value 0.0297). No benefit was observed by double staining. CONCLUSIONS: ECS diagnosis with methylene blue provides a high accuracy rate and good interobserver agreement to predict histology of SNADETs.

Characteristics of microbiomes of the saliva, duodenal bulb, and descending portion of superficial nonampullary duodenal epithelial tumors.

INTRODUCTION: Nonampullary duodenal epithelial tumors are rare, but their prevalence is increasing. Various gastrointestinal cancers have been associated with microbiomes. We evaluated the characteristics of the salivary and duodenal microbiomes of patients with nonampullary duodenal epithelial tumors. METHODS: Saliva and biopsy samples from the duodenal bulb and descending portion were obtained from 15 patients with nonampullary duodenal epithelial tumors and 10 controls. Next-generation sequencing was performed to identify bacteria for comparison. RESULTS: Saliva samples had higher Amplicon Sequence Variants (ASVs) and more observed species than duodenal samples. Saliva samples from patients with nonampullary duodenal epithelial tumor were dominated by Bacteroidetes and Prevotella, whereas Proteobacteria and Neisseria were dominant in the control samples. The relative abundance of bacteria was higher in patients with nonampullary duodenal epithelial tumors. Most bacteria were classified as bacteria of oral origin. Oribacterium and Stomatobaculum were significantly higher in the saliva, duodenal bulb, and descending portion of patients with nonampullary duodenal epithelial tumors. CONCLUSION: Patients with nonampullary duodenal epithelial tumors had different salivary and duodenal microbiomes than controls. Bacteria types differed between groups at each site, and most bacteria of oral origin were more abundant in patients with nonampullary duodenal epithelial tumors.