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Objectives: A computer-aided detection (CAD) system was developed to support the detection of colorectal lesions by deep learning using video images of lesions and normal mucosa recorded during colonoscopy. The study's purpose was to evaluate the stand-alone performance of this device under blinded conditions., Methods: This multicenter prospective observational study was conducted at four Japanese institutions. We used 326 videos of colonoscopies recorded with patient consent at institutions in which the Ethics Committees approved the study. The sensitivity of successful detection of the CAD system was calculated using the target lesions, which were detected by adjudicators from two facilities for each lesion appearance frame; inconsistencies were settled by consensus. Successful detection was defined as display of the detection flag on the lesion for more than 0.5 s within 3 s of appearance., Results: Of the 556 target lesions from 185 cases, detection success sensitivity was 97.5% (95% confidence interval [CI] 95.8-98.5%). The "successful detection sensitivity per colonoscopy" was 93% (95% CI 88.3-95.8%). For the frame-based sensitivity, specificity, positive predictive value, and negative predictive value were 86.6% (95% CI 84.8-88.4%), 84.7% (95% CI 83.8-85.6%), 34.9% (95% CI 32.3-37.4%), and 98.2% (95% CI 97.8-98.5%), respectively., Trial Registration: University Hospital Medical Information Network (UMIN000044622)., (© 2023 Japan Gastroenterological Endoscopy Society.)

Screening endoscopy improves detection and prognosis of patients with gastric cancer. However, even expert endoscopists can miss early gastric cancer under standard white light imaging. Texture and color enhancement imaging (TXI) is an image-enhanced endoscopy that enhances brightness, surface irregularities such elevation or depression, and subtle color changes. A few image-oriented studies have compared the gastric color differences between neoplastic and peripheral areas under both white light imaging and TXI. The results not only suggested that the overall color differences to be more pronounced in TXI, but also that TXI mode 1 was superior to white light imaging in the visibility of early gastric cancer. Despite the promising results in these initial studies, it is unclear whether the superiority of the image-enhanced endoscopy will translate into an improvement in early gastric cancer detection in real practice. Therefore, large-scale prospective studies are necessary to investigate the efficacy of this new technology in the evaluation of patients undergoing screening endoscopy., (© 2021 Japan Gastroenterological Endoscopy Society.)

The Japan Gastroenterological Endoscopy Society developed the Guideline for Endoscopic Diagnosis of Early Gastric Cancer based on scientific methods. Endoscopy for the diagnosis of early gastric cancer has been acknowledged as a useful and highly precise examination, and its use has become increasingly more common in recent years. However, the level of evidence in this field is low, and it is often necessary to determine recommendations based on expert consensus only. This clinical practice guideline consists of the following sections to provide the current guideline: [I] Risk stratification of gastric cancer before endoscopic examination, [II] Detection of early gastric cancer, [III] Qualitative diagnosis of early gastric cancer, [IV] Diagnosis to choose the therapeutic strategy for gastric cancer, [V] Risk stratification after endoscopic examination, and [VI] Surveillance of early gastric cancer., (© 2020 Japan Gastroenterological Endoscopy Society.)

The Japan Gastroenterological Endoscopy Society has developed endoscopic submucosal dissection/endoscopic mucosal resection guidelines. These guidelines present recommendations in response to 18 clinical questions concerning the preoperative diagnosis, indications, resection methods, curability assessment, and surveillance of patients undergoing endoscopic resection for esophageal cancers based on a systematic review of the scientific literature., (© 2020 Japan Gastroenterological Endoscopy Society.)

Objectives: Neoadjuvant chemotherapy (nCT) followed by surgery is one of the standard treatments for resectable esophageal squamous cell carcinoma (ESCC). According to the Response Evaluation Criteria in Solid Tumors, endoscopic evaluation of a primary lesion is not recommended during nCT because of reduced objectivity. This study aimed to develop and validate endoscopic evaluation criteria for nCT., Methods: This study retrospectively investigated patients with T2/3 ESCC who underwent nCT followed by radical esophagectomy across two institutions (test and validation sets). We retrospectively estimated the therapeutic effect by classifying patients according to degree of tumor shrinkage (evaluated with endoscopy) as follows: marked reduction (MR), half reduction (HR), insufficient reduction (IR), and progressive disease (PD). Three endoscopists evaluated patients in the test set. Another three endoscopists evaluated patients in the validation set. We analyzed recurrence-free survival (RFS) 3 years after surgery., Results: Of 129 patients in the test set, 44 had MR, 35 had HR, 44 had IR, and six had PD. The 3-year RFS rates were 55% (overall), 79% (MR), 54% (HR), 35% (IR), and 33% (PD). Of 91 patients in the validation set, 22 had MR, 49 had HR, 18 had IR, and two had PD. The 3-year RFS rates were 54% (overall), 77% (MR), 55% (HR), 22% (IR), and 50% (PD)., Conclusions: Our endoscopic criteria for nCT predicted prognosis; however, future studies are needed to further investigate our criteria before general application in the clinical setting., (© 2019 Japan Gastroenterological Endoscopy Society.)

Objectives: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for solid pancreatic lesions has high diagnostic yield. However, few prospective multicenter studies have been performed. We performed a prospective cohort study to evaluate the efficacy and safety of EUS-FNA for diagnosis of solid pancreatic lesions., Methods: This prospective cohort study involved five hospitals in Japan. The primary outcome was sensitivity of EUS-FNA for diagnosing malignant lesions. We also evaluated parameters of diagnostic sufficiency and the safety of EUS-FNA., Results: In total, 246 patients were enrolled. The absolute values of the parameters evaluated showed no significant differences; however, the percentage changes in the white blood cell counts and C-reactive protein levels after examination were significantly higher, and the percentage change in hemoglobin concentrations was significantly lower. The minor and major complication rates at the time of puncture, 24 h, 7 days and 28 days were 4.1%, 2.8%, 1.6%, and 0.0%, respectively. The true complication rate was 1.2%. The diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 97.2%, 88.0%, 96.2%, 100%, and 81.4%, respectively., Conclusions: EUS-FNA for solid pancreatic lesions has high diagnostic yield and is safe, consistent with previously studies., (© 2019 Japan Gastroenterological Endoscopy Society.)

Background and Aim: Western studies have suggested two distinct etiologies of esophagogastric junction (EGJ) cancer: Helicobacter pylori-associated atrophic gastritis and non-atrophic gastric mucosa resembling esophageal adenocarcinoma. The present study investigated whether endoscopic gastric mucosal atrophy can distinguish between these two types of EGJ adenocarcinoma., Methods: Data were collected from patients with Siewert type II, T1 EGJ adenocarcinoma who underwent endoscopic or surgical resection at eight Japanese institutions in 2010-2015. Clinicopathological characteristics of EGJ cancers with and without endoscopic gastric mucosal atrophy were compared. EGJ was defined as the lower end of the palisade vein and/or the top of the gastric folds., Results: Of the 229 patients identified, 161 had endoscopic gastric mucosal atrophy and 68 did not. The latter group was younger (64 vs 70 years, P = 0.000); had a higher proportion of patients negative for H. pylori (90% vs 47%, P < 0.0001); and had higher rates of gastroesophageal reflux disease symptoms (43% vs 12%, P = 0.017), mucosal breaks (25% vs 15%, P = 0.009), Barrett's esophagus (BE, 78% vs 42%, P < 0.0001), and tumors above the EGJ (81% vs 19%, P < 0.0001) and on the upper-right side (74% vs 38%, P < 0.0001) than the former group. Multivariate analysis showed that H. pylori positivity (odds ratio [OR] = 13.0, P < 0.001), long-segment BE (OR = 0.025, P = 0.033), and longitudinal (OR = 8.6, P = 0.001) and circumferential (OR = 4.7, P = 0.006) tumor locations were independently associated with gastric mucosal atrophy., Conclusion: Two distinct types of EGJ cancer were identified, with and without endoscopic gastric mucosal atrophy. These types were associated with different tumor locations., (© 2017 The Authors. Digestive Endoscopy © 2017 Japan Gastroenterological Endoscopy Society.)

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., (© 2016 The Authors Digestive Endoscopy © 2016 Japan Gastroenterological Endoscopy Society.)

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., (© 2016 The Authors Digestive Endoscopy © 2016 Japan Gastroenterological Endoscopy Society.)

Background and Aim: Endoscopic submucosal dissection (ESD) becomes more difficult with an increased risk of complications if patient sedation is insufficient. We assessed the safety and effectiveness of propofol-based monitored anesthesia care (MAC) without intubation during ESD for early esophageal cancer (EEC) or early gastric cancer (EGC) in the endoscopy room., Methods: We investigated 1013 consecutive patients with 1126 lesions who underwent ESD for EGC/EEC with either MAC or regular sedation by endoscopists (control group) between July 2010 and March 2013. Patient characteristics, endoscopic findings, technical results, body movement, oxygen saturation (SpO2 ), and drug dosages were then examined., Results: MAC was carried out in 137 EGC (16%) and 82 EEC patients (57%), whereas regular sedation was used in 731 EGC (84%) and 63 EEC patients (43%). MAC was conducted in 21% of all ESD procedures. In the MAC and control groups, body movement requiring a third person for control occurred in 30 (22%) and 533 (72%) cases during gastric ESD (P < 0.0001) and in 36 (44%) and 53 (84%) cases during esophageal ESD (P < 0.0001), respectively. The median minimum SpO2 was significantly lower in the MAC group than in the control group during both gastric and esophageal ESD (96% vs 98%, P < 0.0001; 96% vs 98%, P < 0.0004, respectively). MAC did not cause any adverse effects requiring prolongation of hospitalization., Conclusions: Propofol-based MAC without intubation provided a safer treatment environment by significantly reduced body movement and was very effective for difficult cases requiring longer procedure times or more powerful sedation., (© 2015 The Authors. Digestive Endoscopy © 2015 Japan Gastroenterological Endoscopy Society.)

We summarize the current status of endoscopic ultrasound (EUS) for the upper gastrointestinal (GI) tract solely in Asia, focusing on the staging of superficial cancers and the diagnosis of submucosal tumors (SMT), by analysis of questionnaire responses and a literature review. EUS for assessing the depth of superficial cancers of the upper GI tract is useful; however, evidence is lacking to support that EUS is superior to other modalities. The current status of EUS varies across different Asian countries, and standardization of the methods used both during the procedure and for depth subclassification is necessary to evaluate the diagnostic accuracy. Although EUS alone is limited in the diagnosis of SMT, EUS-guided fine-needle aspiration is an effective and safe diagnostic tool. Although there is a role for EUS, there are still many limitations both technically and in terms of accessibility., (© 2014 The Authors. Digestive Endoscopy © 2014 Japan Gastroenterological Endoscopy Society.)

Determination of the risk of lymph-node metastasis is crucial in making appropriate surgical or endoscopic resection therapeutic decisions. The actual number of patients with esophageal adenocarcinomas and esophagogastric junction adenocarcinomas remains relatively low in Japan; therefore, debate still exists as to whether or not intramucosal esophageal adenocarcinoma has a risk of lymph-node metastasis. We report herein a case of lymph-node metastasis in a surgical resection of an esophageal adenocarcinoma with muscularis mucosae invasion, but no lymphovascular involvement., (© 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.)

Endoscopic resection is now a widely accepted treatment for early gastric cancer, having a negligible risk of lymph-node metastasis. Endoscopic submucosal dissection (ESD) is a relatively new endoscopic resection method developed in the mid-1990 s that facilitates en-bloc resection even in patients with large or ulcerative lesions difficult to resect using conventional endoscopic mucosal resection (EMR). However, compared to EMR, ESD requires a longer procedure time and a higher level of technical expertise, in addition to having a slightly greater risk of complications. Endoscopists must be aware of not only the risk factors for, and incidence of, complications, but also how to effectively treat such complications. Perforation and bleeding are the major complications associated with gastric ESD. The perforation and delayed bleeding rates have been reported to range from 1.2% to 5.2% and 0% to 15.6%, respectively, and can usually be managed with appropriate endoscopic treatment. Immediate bleeding during gastric ESD is quite common and controlling such bleeding, which is primarily achieved by carrying out electrocautery, plays a critical role in the successful completion of ESD., (© 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.)

Background and Aim: There have been few previous reports on endoscopic submucosal dissection (ESD) learning curve for early gastric cancer (EGC) so we retrospectively assessed this subject based on experience of our trainees., Methods: Trainees in our center start performing ESDs for lesions in lower third of stomach with hands-on support by experts during first 10 cases and then perform ESDs by themselves primarily with verbal guidance from experts. They are gradually assigned to perform ESDs in middle and upper thirds of stomach. From January 1999 to December 2008, 464 EGC patients, who underwent ESD performed by 13 trainees, were assessed by dividing ESD cases into five training periods (A, 1-10; B, 11-20; C, 21-30; D, 31-40; and E, 41-50). We compared data from B to C, D and E., Results: Lesions in lower third were A/59%, B/57%, C/55%, D/36% and E/40% with B significantly higher than D (p<0.01) and E (p<0.05). Mean tumor sizes were A/13.9 ± 7.5mm, B/18.3 ± 11.4mm, C/19.0 ± 12.5mm, D/19.3 ± 11.7 mm and E/16.8 ± 10.3mm. En-bloc resection rate was 100% in every period. Delayed bleeding / perforation rates were A/0%/1.8%, B/2.8%/1.9%, C/1.9%/2.9%, D/1.1%/0% and E/2.1%/2.1%, respectively. Lower third procedure times were A/76 ± 39, B/90 ± 61, C/70 ± 48, D/60 ± 50 and E/55 ± 26 minutes with B significantly longer than D and E (p<0.05). Middle and upper third procedure times were A/104 ± 80, B/115 ± 68, C/106 ± 67, D/134 ± 86 and E/96 ± 55 minutes., Conclusion: Step-by-step training was highly effective with 100% en-bloc resection rate and few complications. Learning curve point for our trainees to acquire performing ESD in lower third of stomach was 30 cases., (© 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.)

Since it was developed in 1992, endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been widely used and has been adapted for gastrointestinal and perigastrointestinal lesions. A medical literature review to evaluate the role of EUS-FNA for diagnosis of solid pancreatic masses showed a 78-95% sensitivity, 75-100% specificity, 98-100% positive predictive value, 46-80% negative predictive value and a 78-95% accuracy. The reported complication rates of EUS-FNA for pancreatic solid masses were 0-2%, although the criteria for complications varied among the studies. Because of its high diagnostic yield and low complication rate, EUS-FNA is cost-effective and widely applicable for the diagnosis of solid pancreatic masses, and is the best initial and the preferred secondary method compared with other biopsy techniques, such as endoscopic retrograde cholangiopancreatography-guided biopsy, computed tomography/ultrasound-FNA and surgery. Although EUS-FNA is 'a nearly perfected procedure,' controversy remains, such as the most suitable diameter of the needle, the appropriate number of needle passes and the necessity of on-site cytopathological evaluation. Recently investigators reported that using molecular analysis of EUS-FNA samples can achieve a higher diagnostic efficacy. Further research is encouraged to optimize the EUS-FNA procedure to reach its maximum diagnostic yield for solid pancreatic masses., (© 2011 The Authors. Digestive Endoscopy © 2011 Japan Gastroenterological Endoscopy Society.)

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., (© 2010 The Authors. Digestive Endoscopy © 2010 Japan Gastroenterological Endoscopy Society.)