Randomized controlled trial of remimazolam compared with placebo in Japanese patients undergoing upper gastrointestinal endoscopy: Phase III investigator-initiated clinical trial.

OBJECTIVES: To assess the effectiveness of remimazolam against normal saline (placebo) as a sedative agent for endoscopy in a multicenter, randomized, double-blind, investigator-initiated phase III controlled trial. METHODS: We included 48 Japanese patients undergoing upper gastrointestinal endoscopy. For the procedure, an initial remimazolam dose of 3 mg and additional doses of 1 mg were administered, as determined in the phase II clinical study. The primary study end-point was the successful sedation rate during gastrointestinal endoscopy, determined as a Modified Observer's Assessment of Alertness/Sedation score ≤4 before the start of endoscopy, the completion of gastrointestinal endoscopy, and two or fewer additional doses per 6 min. RESULTS: The successful endoscopy sedation rates were 91.9% and 9.1% in the remimazolam and placebo groups, respectively (P < 0.01). The time from the end of endoscopy to arousal was 0.0 (0.0-0.0) min for both groups. The number of additional doses required to achieve sedation was lower in the remimazolam group than that in the placebo group (P < 0.01). CONCLUSIONS: Remimazolam demonstrated a significantly higher sedation effect during upper gastrointestinal endoscopy in Japanese patients with safe and fast recovery compared with placebo.

Hybrid and Conventional Endoscopic Submucosal Dissection for Early Gastric Neoplasms: A Multi-Center Randomized Controlled Trial.

BACKGROUND & AIMS: Hybrid endoscopic submucosal dissection (H-ESD), which incorporates endoscopic submucosal dissection (ESD) with endoscopic mucosal resection, has been developed to make ESD technically easier. This study aimed to determine if H-ESD is superior to conventional ESD (C-ESD) for small early gastric neoplasms (EGNs). METHODS: We conducted a multi-center, prospective, open-label, randomized controlled trial to compare the treatment outcomes of H-ESD and C-ESD (Hybrid-G Trial). Patients with differentiated type intramucosal EGN ≤20 mm in diameter and without ulceration were randomly assigned (1:1) to groups that underwent H-ESD or C-ESD. A single multi-functional snare, SOUTEN (ST1850-20, Kaneka, Medix, Tokyo, Japan), was used for H-ESD. The primary outcome was procedure time. Secondary outcomes included mucosal incision time, time and speed of submucosal dissection, curability, and endoscopic procedural adverse events. RESULTS: A total of 39 and 40 patients underwent H-ESD and C-ESD, respectively. The procedure time of H-ESD was significantly shorter than that of C-ESD (33.16 min vs 62.46 min; H-ESD/C-ESD ratio: 0.53; 95% confidence interval, 0.41-0.69; P < .0001). There was no significant difference in mucosal incision time between the 2 groups; the time and speed of submucosal dissection of H-ESD were significantly shorter than those of C-ESD. No difference was observed between the 2 groups in other outcomes. CONCLUSIONS: H-ESD has significantly shorter procedure time than C-ESD, with high and comparable curability and safety for both H-ESD and C-ESD. H-ESD can be a good option for the endoscopic treatment of small EGNs. (UMIN Clinical Trials Registry, Numbers: UMIN000041244).

Auxiliary diagnosis of subepithelial lesions by impedance measurement during EUS-guided fine-needle biopsy.

BACKGROUND AND AIMS: EUS-guided FNA/biopsy (EUS-FNA/B) is the citerion standard for diagnosing subepithelial lesions (SELs); however, its diagnostic ability for SELs <20 mm is low. We developed a new diagnostic method to differentiate between GI stromal tumor (GIST) and non-GIST by measuring high-frequency impedance (H-impedance) using an EUS-FNB needle. METHODS: The H-impedance of gastric epithelial neoplasms from 16 cases were measured with a conventional impedance probe to confirm whether H-impedance is clinically useful for assessing cell density (study 1). The H-impedance values of exposed SELs from 25 cases with use of the conventional probe (study 2) and nonexposed SELs from 20 cases with use of the EUS-FNB needle probe (study 3) were measured to determine the diagnostic ability of H-impedance for differentiating GISTs from non-GISTs. RESULTS: H-impedance significantly positively correlated with cell density (P = .030) (study 1). The H-impedance of GIST (99.5) measured with a conventional probe was significantly higher than with those of the muscular layer (82.4) and leiomyoma (89.2) (P < .01) (study 2). The H-impedance of GIST measured with the EUS-FNB needle was also significantly higher than that of leiomyoma (GIST: 80.2 vs leiomyoma, 71.8; P = .015). The diagnostic yield of the impedance method for differentiating GISTs from non-GISTs had 94.4% accuracy, 88.9% sensitivity, 100% specificity, and 0.95 area under the curve. Diagnostic ability was not affected by lesion size (P = .86) (study 3). CONCLUSION: Auxiliary differential diagnosis between gastric GISTs and non-GISTs by the H-impedance measurement during EUS-FNB could be a good option, especially when the lesion is <20 mm.

Ampullary Neuroendocrine Neoplasm: Clinicopathological Characteristics and Novel Endoscopic Entity.

BACKGROUND: Neuroendocrine neoplasms of the ampulla of Vater (ampullary NEN) have features of both gastrointestinal and pancreato-biliary (PB) NEN. However, the limited number of studies examining ampullary NEN makes it difficult to clarify their unique characteristics. This study aimed to elucidate the clinical characteristics of ampullary NEN. METHODS: We enrolled 162 patients with PB-NEN diagnosed at Kyushu University Hospital between 2011 and 2020. Clinical features, pathological diagnoses, treatments, and prognoses were retrospectively analyzed. We also compared ampullary NEN with pancreatic NEN (PanNEN). RESULTS: We analyzed 10 ampullary NEN cases and 149 PanNEN cases. The ampullary NEN cases consisted of 4 cases of neuroendocrine tumor Grade 1 (NET G1), 1 NET G2 (Grade 2), and 5 neuroendocrine carcinomas (NECs). The incidences of NEC and cholangitis were significantly higher in ampullary NEN than in PanNEN. All ampullary NETs had a submucosal tumor-like appearance, as identified by endoscopic ultrasound-guided fine needle aspiration. We treated small NET G1 (<10 mm) with endoscopic papillectomy and large NET G1 with pancreaticoduodenectomy. There were no cases of recurrence after resection. All ampullary NECs presented with the characteristic endoscopic finding of a "crater sign" similar to deep-mining ulcers seen in gastric malignant lymphoma. Four cases underwent surgical resection, and 1 case was unresectable. Two patients who underwent multidisciplinary treatment were maintained without recurrence for over 2 years. CONCLUSIONS: Endoscopic findings showed identifiable distinctions between ampullary NETs and NECs.

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.

Development of a new endoscopy system to visualize bilirubin for the diagnosis of duodenogastroesophageal reflux.

OBJECTIVES: Reflux hypersensitivity (RH) is a form of refractory gastroesophageal reflux disease in which duodenogastroesophageal reflux (DGER) plays a role. This study aimed to determine the usefulness of an endoscopy system equipped with image-enhanced technology for evaluating DGER and RH. METHODS: The image enhancement mode for detecting bilirubin and calculated values were defined as the Bil mode and Bil value, respectively. First, the visibility of the Bil mode was validated for a bilirubin solution and bile concentrations ranging from 0.01% to 100% (0.002-20 mg/dL). Second, visibility scores of the Bil mode, when applied to the porcine esophagus sprayed with a bilirubin solution, were compared to those of the blue laser imaging (BLI) and white light imaging (WLI) modes. Third, a clinical study was conducted to determine the correlations between esophageal Bil values and the number of nonacid reflux events (NNRE) during multichannel intraluminal impedance-pH monitoring as well as the utility of esophageal Bil values for the differential diagnosis of RH. RESULTS: Bilirubin solution and bile concentrations higher than 1% were visualized in red using the Bil mode. The visibility score was significantly higher with the Bil mode than with the BLI and WLI modes for 1% to 6% bilirubin solutions (P < 0.05). The esophageal Bil value and NNRE were significantly positively correlated (P = 0.031). The area under the receiver operating characteristic curve for the differential diagnosis of RH was 0.817. CONCLUSION: The Bil mode can detect bilirubin with high accuracy and could be used to evaluate DGER in clinical practice.

Randomized controlled trial comparing conventional and traction endoscopic submucosal dissection for early colon tumor (CONNECT-C trial).

OBJECTIVES: Endoscopic submucosal dissection (ESD) is a widely used treatment for early gastrointestinal cancer. However, colon ESD remains challenging. Previous studies on colon ESD using the traction method used a small sample, single-center design, providing insufficient evidence of this procedure's efficacy. We thus aimed to investigate the efficacy and safety of the traction method in colon ESD in this multicenter randomized trial. METHODS: We conducted a prospective, multicenter, randomized, two-arm controlled trial at 10 facilities in Japan. A 1:1 allocation was conducted for the conventional ESD (C-ESD) and traction ESD (T-ESD) groups. The primary end-point was ESD procedure time. RESULTS: We included 128 C-ESD and 123 T-ESD cases from April 2020 to August 2021. The median procedure times for C-ESD and T-ESD were 61 (40-100) and 53 (40-76) min (P = 0.18), respectively, and no significant differences were observed between the groups. Subgroup analysis showed that the median procedure times for patients with a lesion diameter of ≥30 mm in the C-ESD and T-ESD groups were 89 (57-80) and 69 (50-104) min (P = 0.05), respectively, and for nonexpert operators were 81 (62-120) and 64 (52-109) min (P = 0.07), respectively. CONCLUSIONS: The traction method did not contribute to a significantly shortened ESD procedure time. However, this method may be useful when the tumor diameter is large or if the procedure is conducted by nonexpert endoscopists.

The treatment effects of acotiamide in esophagogastric outflow obstruction: a prospective longitudinal observational study.

OBJECTIVES: We have found that an altered lower esophageal sphincter (LES) accommodation response is an underlying cause of esophagogastric junction outflow obstruction (EGJOO). The objective of this study was to examine the treatment effect of acotiamide, a prokinetic agent which improves impaired gastric accommodation in functional dyspepsia, in patients with EGJOO. METHODS: A prospective observational longitudinal study was conducted between October 2014 and March 2020. Acotiamide (100 mg, 3 times a day) was administered to 25 patients with EGJOO for 4 weeks. High-resolution manometry (HRM) was performed just before and after 4 weeks of treatment. RESULTS: As the primary outcome, the extent of integrated relaxation pressure (IRP) after treatment (14.6, 12.1-22.0 mmHg) was significantly lower than that before treatment (19.4, 17.1-27.4 mmHg). The extent of LES accommodation index after treatment (32.7, 21.0-40.0 mmHg) was also significantly lower than that before treatment (39.3, 31.2-50.2 mmHg). Acotiamide normalized the IRP (< 15 mmHg) in 13 of 25 patients with EGJOO (52%), and the IRP was decreased in 20 of 25 patients with EGJOO (80%). As the secondary outcome, the total FSSG score in 25 patients with EGJOO before and after acotiamide treatment showed no significant difference. In a sub-analysis of 13 patients in whom EGJOO was normalized by acotiamide, however, dysphagia was reported to be significantly improved by acotiamide. CONCLUSIONS: Acotiamide has a treatment effect on patients with EGJOO via a reduction in the IRP level through the lowering of both the basal LES pressure and LES accommodation response. Dysphagia is a key symptom to be evaluated and treated in patients with EGJOO.

Self-Completion Method of Endoscopic Submucosal Dissection Using Endosaber without Any Other Device or Assistance: An ex vivo Porcine Model Study.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a standard treatment for tumors of the gastrointestinal tract. We developed a self-completion method of ESD using Endosaber to eliminate the need for an additional device or human assistance during the procedure. The aim of this study was to evaluate the technical feasibility and outcomes of this method in an ex vivo porcine training model. METHODS: This was a pilot study, and the procedures were performed by 4 experts. Mock lesions measuring 15 mm in diameter were prepared at the posterior wall in the middle or lower esophagus obtained from domestic pigs. Each operator performed ESD on the mock lesions in 3 models. The primary outcome was ESD completion rate using the self-completion method. The secondary outcomes were procedure time, en bloc resection rate, perforation rate, and number of injections during the procedure. RESULTS: All 12 ESDs were completed using the self-completion method. The median procedure time (interquartile range) was 483.5 (399-619.3) s (median incision time: 240.4 [168.3-332.5] s; median dissection time: 222 [182.8-257] s). En bloc resection rate was 100%. No perforation was noted during any of the procedures. The median number of injections was 10.5 (9-14.3). The procedure time decreased significantly with increase in experience (p = 0.020). CONCLUSIONS: The self-completion ESD method using one Endosaber without any assistance achieved a 100% en bloc resection rate without any perforation. The need for an additional device or assistance was successfully eliminated. This method may prove to be a simple and cost-effective ESD procedure for lesions in humans.

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.

The effect of scissor-type versus non-scissor-type knives on the technical outcomes in endoscopic submucosal dissection for superficial esophageal cancer: a multi-center retrospective study.

The Clutch Cutter was invented as a scissor-type knife for endoscopic submucosal dissection (ESD) of gastrointestinal neoplasms. ESD with the scissor-type knife (ESD-S) may be considered a technically easier procedure than ESD with non-scissor-type knives (ESD-NS). Therefore, this study aimed to compare the technical outcomes of ESD-S with those of ESD-NS for superficial esophageal cancer. This was a multicenter retrospective study. Patients with superficial esophageal cancer treated with ESD between October 2015 and March 2018 at three hospitals were retrospectively reviewed. The ESD-S group had 48 patients and the ESD-NS group had 114 patients. A propensity score matching analysis was performed to compensate for the confounding bias between both groups. Multivariate analyses and propensity score matching were used to adjust for age, sex, the tumor size, tumor location, tumor depth, degree of tumor circumference, operator level, usage of the traction method, and the sedation method. The primary outcome was the procedure time of the ESD. Secondary outcomes were the rate of en-bloc/complete resection and the rate of complications including perforation, delayed bleeding, and stricture. Propensity score matching analysis provided 36 matched pairs. Median procedure time in the ESD-S group was significantly shorter than that in the ESD-NS group (44.0 min vs. 66.5 min, P = 0.020). In addition, the treatment outcomes were similar in both groups (en-bloc resection: 100% vs. 97.2%, P = 1; complete resection: 88.9% vs. 86.1%, P = 1; curative resection: 80.6% vs. 77.8%, P = 1; perforation: 0% vs. 5.6%, P = 0.49; delayed bleeding: 0% in both groups; stricture: 2.8% vs. 8.3%, P = 0.61). ESD-S was associated with a shorter procedure time than ESD-NS, without an increase in the incidence of complications. Therefore, the scissor-type knife should be considered as an endo-knife for ESD of superficial esophageal cancers.

Ex vivo porcine model study on the treatment outcomes of scissor-type knife versus needle-type knife in endoscopic submucosal dissection performed by trainees.

BACKGROUND: Endoscopic submucosal dissection (ESD) for gastrointestinal neoplasms can be technically difficult for trainee endoscopists. Presently, there is no consensus for trainees to select the endo-knife type in ESD. Therefore, we conducted a comparison study of treatment outcomes between scissors-type and needle-type knives in ESD performed by trainees in an ex vivo porcine model. METHODS: This study was conducted on trainee endoscopists who participated in ESD hands-on seminars held in August 2018 and September 2019. A total of 22 trainees from 13 institutions were divided into two groups according to their endoscopic experience. Under expert supervision, each trainee performed two ESDs in porcine models, namely, scissor-type knife (ESD-S) and needle-type knife (ESD-N). The efficacy and safety, including the procedure time and rates of self-completion, en bloc resection, and complications, were compared between ESD-S and ESD-N. In subgroup analysis, we also investigated the predictors associated with the difficulty of ESD for trainees using multivariate logistic regression analysis. RESULTS: Eight trainees had an experience of over 1000 endoscopies (senior trainee: S-Trainee), whereas the others had an experience of less than 1000 endoscopies (junior trainee: J-Trainee). Among the S-Trainees, no significant differences were observed in any treatment outcome between ESD-S and ESD-N. Among the J-Trainees, the total procedure and mucosal incision times were significantly shorter in ESD-S than in ESD-N [total procedure time: 16.5 min (range 10.0-31.0) vs. 22.3 min (range 10.0-38.0), P = 0.018; circumferential incision time: 10.0 min (range 6-16) vs. 17.0 min (range 5.0-31.5); P = 0.019]. Regarding complications, muscular injury occurred in two patients during ESD-N performed by J-Trainees; however, no muscular injury occurred during ESD-S. In subgroup analysis, ESD-N was an independent predictive factor of difficult ESD (odds ratio 5.28, 95% confidence interval 1.25-22.30; P = 0.024). CONCLUSIONS: This study revealed that trainees, particularly those who have experienced less than 1000 endoscopies, should opt for the scissor-type knife to perform ESD.

Chronically stimulated human MAIT cells are unexpectedly potent IL-13 producers.

Mucosal-associated invariant T (MAIT) cells are unconventional T cells that recognize antigens derived from riboflavin biosynthesis. In addition to anti-microbial functions, human MAIT cells are associated with cancers, autoimmunity, allergies and inflammatory disorders, although their role is poorly understood. Activated MAIT cells are well known for their rapid release of Th1 and Th17 cytokines, but we have discovered that chronic stimulation can also lead to potent interleukin (IL)-13 expression. We used RNA-seq and qRT-PCR to demonstrate high expression of the IL-13 gene in chronically stimulated MAIT cells, and directly identify IL-13 using intracellular flow cytometry and multiplex bead analysis of MAIT cell cultures. This unexpected finding has important implications for IL-13-dependent diseases, such as colorectal cancer (CRC), that occur in mucosal areas where MAIT cells are abundant. We identify MAIT cells near CRC tumors and show that these areas and precancerous polyps express high levels of the IL-13 receptor, which promotes tumor progression and metastasis. Our data suggest that MAIT cells have a more complicated role in CRC than currently realized and that they represent a promising new target for immunotherapies where IL-13 can be a critical factor.

The Altered Mucosal Barrier Function in the Duodenum Plays a Role in the Pathogenesis of Functional Dyspepsia.

BACKGROUND: An altered gastrointestinal barrier function is reportedly associated with the pathogenesis of functional dyspepsia (FD); however, the pathogenesis of FD has not yet been fully elucidated. AIMS: The objective of the present study was to determine whether the mucosal barrier function is impaired in patients with FD and to investigate the mechanisms underlying FD. METHODS: The present study included patients with FD (FD group, n = 24), non-FD patients with abdominal symptoms (symptomatic control group, n = 14), and patients with no abdominal symptoms (asymptomatic control group, n = 20). The groups were compared regarding the mucosal electrical impedance (MI) values of the stomach and duodenum, which were measured using a tissue conductance meter during esophagogastroduodenoscopy. RESULTS: There were no significant differences between the three groups in the MI of the stomach. In contrast, the duodenal MI of the FD group (17.8 ± 4.3 Ω) was significantly lower than those of the symptomatic control group (27.2 ± 6.4 Ω, p < 0.0001) and asymptomatic control group (23.0 ± 7.4 Ω, p = 0.016). The expression of zonula occludens-1 (ZO-1) was significantly lower in the FD group than in the symptomatic control group (p = 0.011), where ZO-1 was positively correlated with the duodenal MI (ß = 0.513, p = 0.017). The interleukin (IL)-1ß expression was significantly higher in the FD group than in the symptomatic control group (p = 0.041), where IL-1ß was inversely correlated with the duodenal MI (ß = - 0.600, p = 0.004). CONCLUSIONS: The mucosal barrier function of the duodenum was altered in patients with FD. Both a decreased ZO-1 and increased IL-1ß may play a role in the pathogenesis of FD.

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.

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.