Negligible procedure-related dissemination risk of mucosal incision-assisted biopsy for gastrointestinal stromal tumors versus endoscopic ultrasound-guided fine-needle aspiration/biopsy.

BACKGROUND: Mucosal incision-assisted biopsy (MIAB) is a valuable alternative to endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNAB) for sampling gastric subepithelial lesions (SELs). This study aimed to evaluate the potential risk of dissemination and impact on postoperative prognosis associated with MIAB, which has not yet been investigated. METHODS: Study 1: A prospective observational study was conducted to examine the presence or absence and growth rate of tumor cells in gastric juice before and after the procedure in patients with SELs who underwent MIAB (n = 25) or EUS-FNAB (n = 22) between September 2018 and August 2021. Study 2: A retrospective study was conducted to examine the impact of MIAB on postoperative prognosis in 107 patients with gastrointestinal stromal tumors diagnosed using MIAB (n = 39) or EUS-FNAB (n = 68) who underwent surgery between January 2001 and July 2020. RESULTS: In study 1, although no tumor cells were observed in gastric juice in MIAB before the procedure, they were observed in 64% of patients after obtaining samples (P < 0.001). In contrast, no tumor cells were observed in the gastric juice in EUS-FNAB before and after the procedure. In study 2, there was no significant difference in 5-year disease-free survival between MIAB (100%) and EUS-FNAB (97.1%) (P = 0.27). CONCLUSION: MIAB is safe, with little impact on postoperative prognosis, although the procedure releases some tumor cells after damaging the SEL's pseudocapsule.

Feasibility and Efficacy of Endoscopic Ultrasound-Guided Hepaticogastrostomy Without Dilation: A Propensity Score Matching Analysis.

BACKGROUND: Recently, endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) procedures have been gradually established; nonetheless, some adverse events (AEs) have been reported. Dilation procedures using a non-cautery or cautery device increase the incidence of AEs in EUS-HGS. AIMS: We evaluated EUS-HGS procedures without dilation and the factors associated with dilation. METHODS: We enrolled 79 patients who underwent EUS-HGS between July 2015 and March 2021 at two centers, 72 of whom had technical success (72/79, 91%). During the EUS-HGS procedures, we defined patients without dilation procedures as the dilation (-) group. We divided the patients into two groups: the dilation (+) (35 patients) and dilation (-) (37 patients) groups. We performed a propensity score matching analysis to adjust for confounding bias between the two groups. Multivariable logistic regression analysis was conducted to identify factors associated with dilation. RESULTS: There was no difference in clinical success rate between the dilation (+) and dilation (-) groups (91% vs. 95%, P = 0.545). The AE rate (P = 0.013) and long procedure time (P = 0.017) were significantly higher in the dilation (+) group than in the dilation (-) group before and after propensity score matching. Factors associated with dilation were plastic stent placement (odds ratio [OR], 6.96; 95% confidence interval [CI], 1.68-28.7; P = 0.007) and puncture angle of ≤ 90° (OR, 44.6; 95% CI, 5.1-390; P < 0.001). CONCLUSIONS: A dilation procedure in EUS-HGS may not always be necessary. However, patients with an angle of ≤ 90° between the needle and intrahepatic biliary tract or plastic stent deployment require dilation procedures.

Superiority of mucosal incision-assisted biopsy over ultrasound-guided fine needle aspiration biopsy in diagnosing small gastric subepithelial lesions: a propensity score matching analysis.

BACKGROUND: Gastric subepithelial lesions, including gastrointestinal stromal tumors, are often found during routine gastroscopy. While endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) has been the gold standard for diagnosing gastric subepithelial lesions, alternative open biopsy procedures, such as mucosal incision-assisted biopsy (MIAB) has been reported useful. The aim of this study is to evaluate the efficacy of MIAB for the diagnosis of gastric SELs compared with EUS-FNAB. METHODS: We retrospectively analyzed medical records of 177 consecutive patients with gastric SELs who underwent either MIAB or EUS-FNAB at five hospitals in Japan between January 2010 and January 2018. Diagnostic yield, procedural time, and adverse event rates for the two procedures were evaluated before and after propensity-score matching. RESULTS: No major procedure-related adverse events were observed in either group. Both procedures yielded highly-accurate diagnoses once large enough samples were obtained; however, such successful sampling was more often accomplished by MIAB than by EUS-FNAB, especially for small SELs. As a result, MIAB provided better diagnostic yields for SELs smaller than 20-mm diameter. The diagnostic yields of both procedures were comparable for SELs larger than 20-mm diameter; however, MIAB required significantly longer procedural time (approximately 13 min) compared with EUS-FNAB. CONCLUSIONS: Although MIAB required longer procedural time, it outperformed EUS-FNAB when diagnosing gastric SELs smaller than 20-mm diameter.

Mucosal incision-assisted biopsy versus endoscopic ultrasound-guided fine-needle aspiration with a rapid on-site evaluation for gastric subepithelial lesions: A randomized cross-over study.

OBJECTIVES: This study aimed to compare the diagnostic yield of mucosal incision-assisted biopsy (MIAB) and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) with a rapid on-site evaluation (ROSE) for gastric subepithelial lesions (SEL) suspected of being gastrointestinal stromal tumors (GIST) with an intraluminal growth pattern. METHODS: This was a prospective randomized, cross-over multicenter study. The primary outcome was the diagnostic yield of EUS-FNA and MIAB. The secondary outcomes were the technical success rate, complication rate, procedure time and biopsy frequency. RESULTS: A total of 47 patients were randomized to the MIAB group (n = 23) and EUS-FNA group (n = 24). There was no significant difference in the diagnostic yield of MIAB and EUS-FNA (91.3% vs 70.8%, P = 0.0746). The complication rates of MIAB and EUS-FNA did not differ to a statistically significant extent. The mean procedure time in the MIAB group was significantly longer than that in the EUS-FNA group (34 vs 26 min, P = 0.0011). CONCLUSIONS: The diagnostic yield of MIAB was satisfactorily as high as EUS-FNA with ROSE for gastric SEL with an intraluminal growth pattern.

Objective validity of the Japan Narrow-Band Imaging Expert Team classification system for the differential diagnosis of colorectal polyps.

BACKGROUND AND AIM: The Japan Narrow-Band Imaging (NBI) Expert Team (JNET) classification is a recently proposed NBI magnifying endoscopy-based classification system for colorectal tumors. Although the usefulness of this system has been reported by JNET experts, its objective validity remains unclear. We tested its validity and usefulness for the diagnosis of colorectal polyps by including colonoscopy experts and non-experts as test participants. METHODS: Forty NBI images of polyps of various JNET types were shown to 22 doctors (11 experts and 11 non-gastrointestinal [GI] trainees) who had not examined the patients. The doctors diagnosed the polyps based solely on the surface and vessel patterns in the magnified images and the JNET classification system. Concordance rates of their diagnoses with the pathological findings of the polyps were determined, and the results for experts and non-GI trainees were compared. RESULTS: Both for colonoscopy experts and non-GI trainees, the JNET classification system was particularly useful for classifying polyps as benign or malignant. Although the accuracy rates for classifying polyps into each JNET type varied among colonoscopy experts, those who were familiar with the JNET classification system were able to diagnose polyps with approximately 90% accuracy. Common mistakes were attributable to misunderstandings of the wording in the JNET classification chart and lack of proper training. CONCLUSION: The JNET classification system is a practical approach for the diagnosis of colorectal polyps. Training is required even for experienced colonoscopists to adopt the system properly. Common pitfalls must be shared among colonoscopists to improve the accuracy of the diagnosis.

Development of Image-enhanced Endoscopy of the Gastrointestinal Tract: A Review of History and Current Evidences.

Endoscopy imaging of the gastrointestinal (GI) tract has evolved tremendously over the last few decades. Key milestones in the development of endoscopy imaging include the use of various dyes for chromoendoscopy, the application of optical magnification in endoscopy, the introduction of high-definition image capturing and display technology and the application of altered illuminating light to achieve vascular and surface enhancement. Aims of this review paper are to summarize the development and evolution of modern endoscopy imaging and in particular, imaged-enhanced endoscopy (IEE), to promote appropriate usage, and to guide future development of good endoscopy practice. A search of PubMed database was performed to identify articles related to IEE of the GI tract. Where appropriate, landmark trials and high-quality meta-analyses and systematic reviews were used in the discussion. In this review, the developments and evolutions in endoscopy imaging and in particular, IEE, were summarized into discernible eras and the literature evidence with regard to the strengths and weaknesses in term of their detection and characterization capability in each of these eras were discussed. It is in the authors' opinion that IEE is capable of fairly good detection and accurate characterization of various GI lesions but such benefits may not be readily reaped by those who are new in the field of luminal endoscopy. Exposure and training in making confident diagnoses using these endoscopy imaging technologies are required in tandem with these new developments in order to fully embrace and adopt the benefits.

Mucosally Expressed Cytokines are Associated with the Esophageal Motility Function.

BACKGROUND AND AIM: Although basic research has shown that certain cytokines affect gastrointestinal motility, the clinical evidence is lacking. The objective of this study was to explore the association between mucosally expressed cytokines and the esophageal motility function in humans. METHODS: We enrolled a total of 57 patients with suspected esophageal motility disorders (EMDs) who underwent high-resolution manometry. RESULTS: The diagnoses of the patients were as follows: normal esophageal motility (n = 25), ineffective esophageal motility (n = 5), esophagogastric junction outflow obstruction (EGJOO; n = 10), distal esophageal spasm (n = 5), achalasia (n = 10), absent contractility (n = 1), and jackhammer esophagus (n = 1). The expression of tumor necrosis factor (TNF)-α in the esophagogastric junction (EGJ) was significantly higher in EGJOO (14.6, 14.0-15.8, n = 10) than in normal esophageal motility (13.3, 12.8-14.1, n = 25); however, there was no difference in the expression of TNF-α between achalasia (13.4, 13.0-14.1, n = 10) and normal esophageal motility (13.3, 12.8-14.1, n = 25). EGJOO was discriminated from achalasia/normal by a linear discriminant analysis (AUC = 0.917). A multivariable regression analysis revealed that interleukin (IL)-13 and IL-23A were predictive of the distal contractile integral, whereas TNF-α and IL-6 were predictive of the basal EGJ pressure. CONCLUSIONS: The esophageal motility was associated with mucosally expressed cytokines in humans; these cytokines could be useful targets for the diagnosis and treatment of EMDs.

[A case of non-cardiac chest pain caused by esophageal motility disorder observed on esophageal high-resolution manometry].

A 20-year-old man was referred to our hospital with dysphagia and chest pain. Heart disease was denied. No abnormality was observed in upper esophagogastroduodenoscopy and fluoroscopy;furthermore, no gastric acid-related symptoms were observed on combined esophageal multichannel intraluminal impedance and pH monitoring. Esophageal high-resolution manometry (HRM) performed by liquid swallow revealed normal peristalsis;however, HRM performed while the patient was taking solid meals showed abnormal contraction, and the patient simultaneously complained of chest pain. Therefore, we diagnosed this case as non-cardiac chest pain due to esophageal motility disorder.

Gastric neuroendocrine tumor with hypergastrinemia following type B chronic atrophic gastritis: a case report.

A man in his 60s was referred to our institution for the evaluation of a gastric neuroendocrine tumor (G-NET) located in the fornix and that measured 13mm in size. Blood test results revealed hypergastrinemia (up to 3376pg/ml). Additional tests, including esophagogastroduodenoscopy, computed tomography, and intragastric pH monitoring, indicated that hypergastrinemia was not associated with type A autoimmune gastritis or gastrinoma. The patient was positive for the immunoglobulin G antibody against Helicobacter pylori, suggesting type B chronic atrophic gastritis as the cause for the condition. This report describes a rare case of G-NET with hypergastrinemia following type B chronic atrophic gastritis. Evaluation of similar cases is necessary to determine if H. pylori-associated chronic atrophic gastritis is frequently associated with G-NET.

Efficacy of endoscopic ultrasonography and endoscopic ultrasonography-guided fine-needle aspiration for the diagnosis and grading of pancreatic neuroendocrine tumors.

BACKGROUND AND AIM: Pancreatic neuroendocrine tumors (pNETs) are histologically categorized according to the WHO 2010 classification by their mitotic index or Ki-67 index as G1, G2, or G3. The present study examined the efficacy of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) in the diagnosis and grading of pNET. METHODS: We retrospectively reviewed 61 pNETs in 51 patients who underwent EUS between January 2007 and June 2014. All lesions were pathologically diagnosed by surgical resection or EUS-FNA. We evaluated the detection rates of EUS for pNET and sensitivity of EUS-FNA, and compared the Ki-67 index between EUS-FNA samples and surgical specimens. EUS findings were compared between G1 and G2/G3 tumors. RESULTS: EUS showed significantly higher sensitivity (96.7%) for identifying pNET than CT (85.2%), MRI (70.2%), and ultrasonography (75.5%). The sensitivity of EUS-FNA for the diagnosis of pNET was 89.2%. The concordance rate of WHO classification between EUS-FNA and surgical specimens was 69.2% (9/13). The concordance rate was relatively high (87.5%, 5/6) in tumors <20 mm but lower (57.1%; 4/7) in tumors ≥20 mm. Regarding EUS findings, G2/G3 tumors were more likely to be large (>20 mm), heterogeneous, and have main pancreatic duct (MPD) obstruction than G1 tumors. Multivariate analysis showed large diameter and MPD obstruction were significantly associated with G2/G3 tumors. CONCLUSIONS: EUS and EUS-FNA are highly sensitive and accurate diagnostic methods for pNET. Characteristic EUS findings such as large tumor size and MPD obstruction are suggestive of G2/G3 tumors and would be helpful for grading pNETs.

Differences in routine esophagogastroduodenoscopy between Japanese and international facilities: A questionnaire survey.

BACKGROUND AND AIM: The mortality rate of gastric cancer (GC) is close to the incidence rate worldwide. However, in Korea and Japan, the mortality rate of GC is less than half of the incidence rate. We hypothesized that good-quality routine esophagogastroduodenoscopy (EGD) contributes to a high detection rate for early GC (EGC) and improves mortality in these countries. METHODS: To clarify the differences in routine EGD, a questionnaire survey was conducted in 98 Japanese and 53 international institutions. RESULTS: Prevalence of screening examination among routine EGD was higher in Japanese than in international institutions. Japanese endoscopists noted that endoscopic mucosal atrophy was the most significant risk factor for GC, whereas international endoscopists paid more attention to clinical information such as age, symptoms and family history. Antispasmodics, mucolytics and defoaming agents were used more frequently in Japanese institutions. The examination time was similar (mostly 5-10 min) between Japanese and international institutions. Japanese endoscopists took more pictures (>20 in almost all institutions) than international endoscopists (≤20 in two-thirds of institutions). In Japanese institutions, biopsy specimens were more frequently taken from areas of mucosal discoloration, unevenness or spontaneous bleeding rather than from obvious endoscopic lesions such as ulceration or polyps. In most Japanese institutions, one or two biopsy specimens were taken per lesion, compared with ≥three in international institutions. CONCLUSION: There were some discrepancies between Japanese and international institutions for routine EGD. Thus, standardization is required for adequate risk assessment, proper techniques, and knowledge of endoscopic diagnosis of EGC.

Basic principles and practice of gastric cancer screening using high-definition white-light gastroscopy: Eyes can only see what the brain knows.

Endoscopic diagnosis of gastrointestinal tumors consists of the following processes: (i) detection; (ii) differential diagnosis; and (iii) quantitative diagnosis (size and depth) of a lesion. Although detection is the first step to make a diagnosis of the tumor, the lesion can be overlooked if an endoscopist has no knowledge of what an early-stage 'superficial lesion' looks like. In recent years, image-enhanced endoscopy has become common, but white-light endoscopy (WLI) is still the first step for detection and characterization of lesions in general clinical practice. Settings and practice of routine esophagogastroduodenoscopy (EGD) such as use of antispasmodics, number of endoscopic images taken, and observational procedure are customarily decided in each facility in each country and are not well standardized. Therefore, in the present article, we attempted to outline currently available evidence and actual Japanese practice on gastric cancer screening using WLI, and provide tips for detecting EGC during routine EGD which could become the basis of future research.

New Approach to Diagnosis and Treatment of Esophageal Motility Disorders by High-Resolution manometry.

Esophageal motility disorders (EMD) is characterized by impaired coordinated esophageal motility function with symptoms including dysphasia, heartburn or noncardiac chest pain. Since EMDs is functional disorders, it is usually difficult to make a diagnosis by conventional examinations including endoscopy and esophagography. Recently developed high-resolution manometry allows us to evaluate esophageal motility function precisely and to make a differential diagnosis of EMDs, together with Chicago Classification (CC) version 3.0 (CC ver3.0). In this article, we reviewed diagnosis of EMDs based on CC ver3.0 and current treatment strategy for EMDs.

Key endoscopic ultrasound features of pancreatic ductal adenocarcinoma smaller than 20 mm.

BACKGROUND AND STUDY AIMS. Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis compared with other solid pancreatic tumors. Diagnosis of PDAC in the earliest possible stage is important to improve the prognosis. Although endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been the gold-standard modality for diagnosing pancreatic lesions, its diagnostic yield is not satisfactory for pancreatic tumors smaller than 20 mm. The purpose of this study was to determine the EUS findings that are useful for differentiating PDAC from other solid pancreatic tumors when the lesions are smaller than 20 mm. PATIENTS AND METHODS. We performed a retrospective review of 126 patients with pancreatic tumors smaller than 20 mm who had undergone EUS. According to the final pathological diagnoses, they were categorized into either the PDAC or non-PDAC group. We, then, compared the EUS findings between the two groups. RESULTS. Among the 126 patients, we diagnosed PDAC in 75 patients and non-PDAC in the remaining patients, including neuroendocrine tumor in 43 patients, intraductal papillary mucinous carcinoma in 3 patients, solid pseudopapillary neoplasm in 2 patients, and inflammatory pseudotumor in 3 patients. Of all EUS findings, three factors were significantly indicative of PDAC: an irregular tumor edge, main pancreatic duct dilation, and tumor location in the pancreatic head. The predicted probability for PDAC was 80%, 92.6%, and 74.1%, respectively. CONCLUSIONS. EUS could be a useful modality for differentiating PDAC from other solid pancreatic tumors, when the diagnostic yield of EUS-FNA is unsatisfactory, even for lesions smaller than 20 mm.

Role of ERCP in the era of EUS-FNA for preoperative cytological confirmation of resectable pancreatic ductal adenocarcinoma.

PURPOSE: In patients with pancreatic ductal carcinoma (PDAC), EUS-FNA carries a risk of cancer seeding. To avoid this risk, we attempted to obtain preoperative cytological confirmation of adenocarcinoma by ERCP. The aim of this study was to assess the validity of our diagnostic strategy. METHODS: The medical records of 124 consecutive patients who were investigated for potentially resectable PDAC were retrospectively reviewed, and the ability to detect adenocarcinoma by ERCP was evaluated. RESULTS: ERCP was performed in 115 patients, 69 of whom had positive cytology results. Thirty-four patients underwent EUS-FNA, 29 of whom had positive cytology results. A total of 98 patients (79 %), therefore, had preoperative cytological confirmation of adenocarcinoma, which was more frequent in patients with lesions of the head of the pancreas than in those with lesions of the body or tail of the pancreas. The postoperative pathological diagnosis demonstrated malignant pancreatic neoplasms in 122 patients (98 %), including 111 with PDAC. EUS-FNA did not affect the rate of postoperative peritoneal dissemination. CONCLUSIONS: Our strategy using ERCP as the initial diagnostic modality for obtaining cytological confirmation of potentially resectable PDAC seems to be adequate, yielding a high rate of positive cytology, especially in cases with tumors of the head of the pancreas.

Large area of walled-off pancreatic necrosis successfully treated by endoscopic necrosectomy using a grasping-type scissors forceps.

Endoscopic necrosectomy (EN) for walled-off pancreatic necrosis (WOPN) is less invasive than surgical treatment and has become the first choice for pancreatic abscess. EN is usually carried out with several devices including snares, baskets, and grasping forceps. Occasionally, we have encountered cases in which EN has not been satisfactorily carried out, and there is pressure for further innovation in EN. Here, we describe a case of a large area of WOPN that was successfully treated by EN with endoscopic submucosal dissection and associated techniques, which facilitated removal of necrotic tissues. A 60-year-old man was referred to our hospital for WOPN as a complication of necrotizing pancreatitis. As a result of his complicating conditions including ischemic heart disease, uncontrollable arrhythmia, chronic renal failure, and persistent pleural effusion, he was deemed a poor surgical candidate. Although EN with conventional devices was carried out for five sessions, we could not remove the dense and massive necrotic tissues. At the sixth EN session, the Clutch Cutter device (Fujifilm, Tokyo, Japan) was used to remove the necrotic tissues, without major complications. This is believed to be the first report of EN using the Clutch Cutter for successful treatment of WOPN.

Prospective, randomized, double-blind, placebo-controlled trial of ulinastatin for prevention of hyperenzymemia after double balloon endoscopy via the antegrade approach.

BACKGROUND: Double balloon endoscopy (DBE) allows the entire small intestine to be viewed using a combination of antegrade and retrograde approaches. Acute pancreatitis is a serious complication of antegrade DBE with no effective prophylactic treatment currently available. Ulinastatin has been shown to be effective for the prevention of pancreatitis following endoscopic retrograde cholangiopancreatography. We therefore assessed the efficacy of ulinastatin for hyperenzymemia after antegrade DBE. PATIENTS AND METHODS: Forty-four patients were enrolled in this prospective, randomized, double-blind, placebo-controlled trial. Patients in the ulinastatin group received 150 000 U ulinastatin by i.v. drip infusion for 2 h from the start of the procedure. Serum concentrations of pancreatic amylase and lipase were measured before and 3 and 18 h after antegrade DBE. RESULTS: The study was terminated after interim analysis. Of the 44 patients, 23 were randomized to ulinastatin and 21 to placebo.The groups were similar with regard to sex ratio, age, type of endoscope, insertion time, total procedure time, number of endoscope pull-back procedures, and baseline pancreaticamylase and lipase concentrations. Post-DBE hyperenzymemia was observed in 35.0% and 47.8% of patients in the placebo and ulinastatin groups, respectively. The higher frequency of hyperenzymemia in the ulinastatin group was unexpected, but the difference was not statistically significant. One patient in the placebo group (5.0%) and none in the ulinastatin group experienced acute pancreatitis, but the difference was not statistically significant. CONCLUSION: The results of this trial suggest that ulinastatin does not prevent hyperenzymemia following antegrade DBE.

[A case of lymph node metastasis from esophageal small-cell-type endocrine cell carcinoma diagnosed by endoscopic ultrasound-guided fine-needle aspiration].

A 70-year-old man presented with a 0-IIc lesion in the lower esophagus. He underwent esophageal endoscopic submucosal dissection (ESD). The pathological diagnosis was squamous cell carcinoma with small cell carcinoma. The patient received chemoradiotherapy after ESD, but this was interrupted because of myelosuppression. Follow-up endoscopic ultrasonography (EUS) at 5 months after the ESD revealed paracardial lymph node swelling (17mm). He underwent EUS-guided fine-needle aspiration (FNA), and lymph node metastasis of small-cell-type endocrine cell carcinoma was diagnosed. He received VP-16 chemotherapy but died 22 months after the ESD.

Low-frequency of bacteremia after endoscopic submucosal dissection of the stomach.

BACKGROUND: Mainstream therapy for early gastric cancer in Japan has now shifted from endoscopic mucosal resection (EMR) to endoscopic submucosal dissection (ESD). Although bacteremia is reported as being infrequent and transient in gastric EMR, there are no reports of it being investigated in gastric ESD. This study aimed to determine the frequency of bacteremia in gastric ESD. PATIENTS AND METHODS: A prospective study, in 46 consecutive patients who underwent gastric ESD, investigated the frequency of bacteremia before and after the procedure. RESULTS: The median time for the total ESD procedure was 105min (range 30-400). The median volume of the submucosal injection was 80ml (range 20-260). The mean size of the resected specimen was 40±9.7mm. Blood cultures obtained before ESD were positive in 4.4% (2/45) of cases. Bacillus subtilis and Bacillus spp. were the isolated microorganisms. Blood cultures obtained 10min after ESD were positive in 4.3% (2/46) of cases; with the same microorganisms being isolated. Blood cultures obtained 3h after ESD were all negative. No signs of sepsis were seen in the two patients with a positive blood culture 10min after ESD. CONCLUSIONS: The frequency of bacteremia after gastric ESD was low and transient. ESD for gastric lesions is thought to have a low risk of infectious complications; therefore, prophylactic administration of antibiotics may not be warranted.