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Background and Aim: Anticoagulant users with nonvalvular atrial fibrillation (NVAF) sometimes suffer from gastrointestinal bleeding (GIB) and have difficulty continuing the medication. Left atrial appendage closure (LAAC) has been developed for such situations. We aimed to clarify the clinical significance of a history of GIB in comparison to other factors in patients who had undergone LAAC. Methods: From October 2019 to September 2023, patients with NVAF who underwent LAAC at our hospital were enrolled. We investigated the percentage of patients with a history of GIB who underwent LAAC and compared the incidence of post‐LAAC bleeding in these patients compared to those with other factors. Results: A total of 45 patients were included. There were 19 patients (42%) with a history of GIB who underwent LAAC. In a Kaplan–Meier analysis, the cumulative incidence of bleeding complications after LAAC was significantly higher in patients with a history of GIB in comparison to patients with other factors. There were eight cases of post‐LAAC bleeding in total, and seven cases had GIB. Conclusions: We need to recognize that GIB is a significant complication in patients who undergo LAAC. The management of GIB by gastroenterologists is essential to the success of LAAC. [ABSTRACT FROM AUTHOR]

Background and Aim: The endoscopic features of gastric neuroendocrine carcinoma (G‐NEC) have not been clarified; therefore, they were investigated in relation to clinicopathological findings. Methods: Consecutive patients with G‐NECs who had undergone endoscopic or surgical resection at our institution between January 2005 and March 2022 were included in this retrospective study. The endoscopic and clinicopathological findings of the lesions were analyzed to provide information of diagnostic value. In addition, cases of gastric neuroendocrine tumor (G‐NET) and common‐type gastric adenocarcinoma treated in the same study period were identified to compare the endoscopic findings between each G‐NEC versus G‐NET, and G‐NEC versus common‐type gastric adenocarcinoma. Patients with common‐type gastric adenocarcinoma were matched for age, sex, tumor size, and depth of tumor invasion in 1:3 ratio. Results: Among 15 patients with 15 G‐NECs, submucosal tumor‐like marginal elevation (87%), adherent white coat (67%), and ulceration with a distinct border (60%) were characteristic endoscopic findings in white‐light images. Magnifying narrow‐band imaging endoscopy revealed an absent microsurface (MS) pattern plus disrupted irregular microvessel (MV) in five (71%) of seven cases with evaluable MS and MV patterns. The area with an absent MS pattern plus disrupted irregular MV corresponded to the histological finding of NEC component in all five cases. These endoscopic features were all significantly more frequent in G‐NECs than G‐NETs (n = 22) or common‐type gastric adenocarcinomas (n = 45). Conclusions: These endoscopic features should be taken into consideration to increase the index of suspicion and to improve the accuracy of target biopsies for G‐NEC. [ABSTRACT FROM AUTHOR]

Background and Aim: Although endoscopic resection with careful surveillance instead of total proctocolectomy become to be permitted for visible low‐grade dysplasia, it is unclear how accurately endoscopists can differentiate these lesions, as classifying neoplasias occurring in inflammatory bowel disease (IBDN) is exceedingly challenging due to background chronic inflammation. We evaluated a pilot model of an artificial intelligence (AI) system for classifying IBDN and compared it with the endoscopist's ability. Methods: This study used a deep convolutional neural network, the EfficientNet‐B3. Among patients who underwent treatment for IBDN at two hospitals between 2003 and 2021, we selected 862 non‐magnified endoscopic images from 99 IBDN lesions and utilized 6 375 352 images that were increased by data augmentation for the development of AI. We evaluated the diagnostic ability of AI using two classifications: the "adenocarcinoma/high‐grade dysplasia" and "low‐grade dysplasia/sporadic adenoma/normal mucosa" groups. We compared the diagnostic accuracy between AI and endoscopists (three non‐experts and four experts) using 186 test set images. Results: The diagnostic ability of the experts/non‐experts/AI for the two classifications in the test set images had a sensitivity of 60.5% (95% confidence interval [CI]: 54.5–66.3)/70.5% (95% CI: 63.8–76.6)/72.5% (95% CI: 60.4–82.5), specificity of 88.0% (95% CI: 84.7–90.8)/78.8% (95% CI: 74.3–83.1)/82.9% (95% CI: 74.8–89.2), and accuracy of 77.8% (95% CI: 74.7–80.8)/75.8% (95% CI: 72–79.3)/79.0% (95% CI: 72.5–84.6), respectively. Conclusions: The diagnostic accuracy of the two classifications of IBDN was higher than that of the experts. Our AI system is valuable enough to contribute to the next generation of clinical practice. [ABSTRACT FROM AUTHOR]

Background and Aim: Recently, artificial intelligence (AI) has been used in endoscopic examination and is expected to help in endoscopic diagnosis. We evaluated the feasibility of AI using convolutional neural network (CNN) systems for evaluating the depth of invasion of early gastric cancer (EGC), based on endoscopic images. Methods: This study used a deep CNN model, ResNet152. From patients who underwent treatment for EGC at our hospital between January 2012 and December 2016, we selected 100 consecutive patients with mucosal (M) cancers and 100 consecutive patients with cancers invading the submucosa (SM cancers). A total of 3508 non‐magnifying endoscopic images of EGCs, including white‐light imaging, linked color imaging, blue laser imaging‐bright, and indigo‐carmine dye contrast imaging, were included in this study. A total of 2288 images from 132 patients served as the development dataset, and 1220 images from 68 patients served as the testing dataset. Invasion depth was evaluated for each image and lesion. The majority vote was applied to lesion‐based evaluation. Results: The sensitivity, specificity, and accuracy for diagnosing M cancer were 84.9% (95% confidence interval [CI] 82.3%–87.5%), 70.7% (95% CI 66.8%–74.6%), and 78.9% (95% CI 76.6%–81.2%), respectively, for image‐based evaluation, and 85.3% (95% CI 73.4%–97.2%), 82.4% (95% CI 69.5%–95.2%), and 83.8% (95% CI 75.1%–92.6%), respectively, for lesion‐based evaluation. Conclusions: The application of AI using CNN to evaluate the depth of invasion of EGCs based on endoscopic images is feasible, and it is worth investing more effort to put this new technology into practical use. [ABSTRACT FROM AUTHOR]

Some situations may require endoscopy during the COVID‐19 (Coronavirus Disease 2019) pandemic. Here, we describe the necessary precautions in the form of clinical questions and answers (Q&A) regarding the safe deployment of gastrointestinal endoscopy in such situations while protecting endoscopy staff and patients from infection. Non‐urgent endoscopy should be postponed. The risk of infection in patients should be evaluated in advance by questionnaire and body temperature. The health of staff must be checked every day. Decisions to employ endoscopy should be based on the institutional conditions and aims of endoscopy. All endoscopic staff need to wear appropriate personal protective equipment (PPE). The endoscope and other devices should be cleaned and disinfected after procedures in accordance with the relevant guidelines. Optimal management of the endoscopy unit is required. Endoscopy for infected patients or those with suspected infection demands exceptional caution. When a patient who undergoes endoscopy is later found to have COVID‐19, the members of staff involved are considered exposed to the virus and must not work for at least 14 days if their PPE is considered insufficient. When PPE resources are limited, some equipment may be used continuously throughout a shift as long as it is not contaminated. Details of the aforementioned protective measures are described. [ABSTRACT FROM AUTHOR]

Background and Aim: Underwater endoscopic mucosal resection (UEMR) has become widespread for treating colorectal polyps. However, which observational mode is best suited for determining polyp margins underwater remains unclear. To determine the best mode, we analyzed three imaging modes: white light imaging (WLI), blue laser imaging (BLI) and linked color imaging (LCI). Methods: Images of consecutive colorectal polyps previously examined by these three modes before UEMR were analyzed according to the degree of underwater turbidity (transparent or cloudy). Color differences between the polyps and their surroundings were calculated using the Commission Internationale d'Eclairage Lab color space in which 3‐D color parameters were expressed. Eight evaluators, who were blinded to the histology, scored the visibility from one (undetectable) to four (easily detectable) in both underwater conditions. The color differences and visibility scores were compared. Results: Seventy‐three polyps were evaluated. Sixty‐one polyps (44 adenomatous, 17 serrated) were observed under transparent conditions, and 12 polyps (seven adenomatous, five serrated) were observed under cloudy conditions. Under transparent conditions, color differences for the BLI (8.5) and LCI (7.9) were significantly higher than that of WLI (5.7; P < 0.001). Visibility scores for BLI (3.6) and LCI (3.4) were also higher than that of WLI (3.1; P < 0.0001). Under cloudy conditions, visibility scores for LCI (2.9) and WLI (2.7) were significantly higher than that of BLI (2.2; P < 0.0001 and P = 0.04, respectively). Conclusions: BLI and LCI were better observational modes in transparent water; however, BLI was unsuitable for cloudy conditions. [ABSTRACT FROM AUTHOR]

All gastrointestinal endoscopic procedures have a high risk of aerosol contamination of the coronavirus disease 2019 (COVID‐19) to endoscopists, nurses, and healthcare assistants. Given the current pandemic situation of COVID‐19, the Japan Gastroenterological Endoscopy Society issued the recommendation for gastrointestinal (GI) endoscopy based on the status of COVID‐19 as of April 9, 2020, in Japan: (i) indications for GI endoscopy in the pandemic of COVID‐19; (ii) practical protective equipment for medical personnel depending on the risk for COVID‐19; (iii) preprocedural management, such as pharyngeal local anesthesia using lidocaine spray which has a potential to generate the aerosols; (iv) ideal settings of the endoscopy room including the numbers of the staff and the patients; (v) postprocedural management, such as undressing and follow‐up of the patients, as well as the involved staff, were documented to fit the practical scenarios in GI endoscopy, with the available data in Japan and the world. We believe that certain measures will prevent further spread of COVID‐19. [ABSTRACT FROM AUTHOR]

Transoral endoscopy with narrow band imaging (NBI) is useful for early detection of head and neck (HN) cancer. However, the lateral and anterior walls of the oropharynx, postcricoid area, and posterior wall of the hypopharynx are difficult to observe using transoral endoscopy. Advanced cancers in these regions may be missed even when NBI is used. This report highlights a method of transoral endoscopic examination of the HN region. For observation of the oral cavity and oropharynx, it is important to observe these regions without using a mouthpiece. Wide opening of the mouth facilitates observation of the oral cavity and oropharynx. Moreover, visibility of the oropharynx, including the anterior wall, is dramatically improved, when the patient positions the tongue forward and says ‘aaah.’ This technique also facilitates observation of the dorsum of the tongue, which is difficult to observe from a tangential view when using a mouthpiece. To observe the hypopharynx, the Valsalva maneuver is very useful. Patient cooperation is important when observing the HN region thoroughly to gain clear endoscopic views. Narcotic drugs, such as pethidine hydrochloride, are ideal for conscious sedation and reduce the gag reflex while still allowing patient cooperation. From the oral cavity to the hypopharynx, including the lateral and anterior walls of the oropharynx, postcricoid area, and posterior wall of the hypopharynx, most of the HN region can be observed during routine examination using transoral endoscopy without any special devices. [ABSTRACT FROM AUTHOR]

Abstract: Background and Aim: The safety of gastric endoscopic submucosal dissection (ESD) in the antithrombotic drug users remains controversial. Methods: Patients who underwent gastric ESD at Okayama University Hospital between March 2006 and February 2016 were enrolled. This study investigated the risk of post‐ESD bleeding according to the management of the antithrombotic drugs. Results: One thousand twenty lesions (872 patients) were enrolled. In a multivariate analysis, heparin replacement (odds ratio [OR] 5.0, 95% confidence interval [CI] 1.8–14), multiple antithrombotic drug use (OR 2.9, 95% CI 1.1–6.9), a resected specimen of ≥ 33 mm in diameter (OR 2.7, 95% CI 1.5–5.4), Helicobacter pylori negativity (OR 2.2, 95% CI 1.3–3.7), and tumors located in the lower third of the stomach (OR 1.7, 95% CI 1.0–2.9) were significant risk factors for post‐ESD bleeding, while the continuation of aspirin or cilostazol was not (OR 2.6, 95% CI 0.72–7.8). The bleeding rate of the continuation group was comparable with that of the all cessation group among single antithrombotic drug users (4.5% vs 4.4%, P = 1.0); however, the rate of the continuation group was significantly higher than that of the all cessation group among multiple antithrombotic drug users (67% vs 15%, P = 0.020). Conclusions: The risk of post‐ESD bleeding differed according to the management of the antithrombotic drugs. The gastric ESD under the cessation or continuation of aspirin or cilostazol monotherapy was acceptable. However, multiple antithrombotic drug use or heparin replacement was associated with a higher risk of post‐ESD bleeding. [ABSTRACT FROM AUTHOR]

Reported herein is the case of a 80-year-old man who had small squamous cell carcinoma in the esophagus. The lesion was initially detected as a irregular reddish elevated and flat area depicted by non-magnified white light endoscopy and observed as a brownish area with the narrow-band imaging system (NBI). The depth of elevated and depressed area in the lesion was predicted to be LSM to MM due to Inoue's classification of morphologic change of intrapapillary capillary loop (IPCL) under magnified NBI observation. The depth of another flat area was not able to predicted by Inoue's classification, and we used Arima's classification. We predicted the depth of invasion to be MM to SM1.by this classification. Endoscopic submucosal dissection (ESD) was carried out for the lesion. As a result, the endoscopic diagnosis completely accorded with pathological diagnosis. We could diagnose correctly by adding Arima's classification to Inoue's classification. [ABSTRACT FROM AUTHOR]

In Asian countries, squamous cell carcinoma is the most common type of esophageal cancer, and the incidence of gastric cancer remains have plateaued. To synthesize current information and to illustrate its clinical benefit of narrow band imaging (NBI) for diagnosis of superficial esophageal squamous carcinoma (SESCC) and early gastric cancer (EGC), a consensus conference was held by a panel of nine experts from Asian-Pacific countries. The expert's agreement suggested importance of interpretation of both vascular architecture and surface structure of the lesions and proper processor settings for endoscopic images. Zoom endoscopy was not regarded as absolutely necessary for detection of SESCC, but magnifying observation provided valuable information for characterization of detected lesions in the esophagus and the stomach. In general, NBI is useful for detection and characterization of SESCC, whereas it is beneficial mainly for characterization of EGC. Chromoendoscopy was found to be still worthwhile in certain situations, such as determination of the extent of SESCC by Lugol's staining, or detection and delineation of EGC by indigo carmine. NBI could replace chromoendoscopy in routine examination because it is easy to use and adds much information to conventional WLI, but it cannot eliminate chromoendoscopy when we make a final diagnosis for treatment decision-making. Consequently, the benefit of NBI or magnifying NBI is specific for the organ and the purpose of the examination, thus optimum indication and usage should be understood for maximum clinical benefit. [ABSTRACT FROM AUTHOR]

Endoscopic submucosal dissection (ESD) can successfully resect large lesions en bloc, but it requires a satisfactory submucosal (sm) injection agent for proper safety and efficacy. The aim of the present study was to evaluate the effectiveness of carbon dioxide (CO) as an ESD sm injection agent. In vitro study using porcine stomachs compared CO with normal saline (NS) and sodium hyaluronic acid (SHA) solution, both of which are currently used to provide long-lasting sm elevation during ESD. Histopathological examination assessed differences between CO and NS sm cushions. ESD were then carried out in vivo in the stomach and rectum of a live pig using CO sm injection. CO sm elevation was significantly longer lasting than either NS or SHA ( P < 0.001). Histopathology revealed no mucosal layer tissue damage, and dissection of honeycomb-like fibrous connective tissue in the CO sm cushion. Creating and maintaining a CO sm cushion of sufficient elevation combined with partial physical dissection of the sm layer was achieved, followed by complete endoscopic dissection of the sm layer with all ESD, resulting in successful en-bloc resections having a mean specimen size of 24.3 mm within 15 min. Safety and efficacy of CO as a satisfactory sm injection agent during ESD was successfully demonstrated in these preliminary studies, warranting further investigation of this innovative technique. [ABSTRACT FROM AUTHOR]

The recent trend of gastroduodenal ulcer bleeding in Japan has not been elucidated in detail and the data for a new categorized type, artificial ulcer bleeding, is completely lacking. The purpose of this paper is to elucidate current managements and outcomes of peptic and artificial ulcer bleeding in Japan. A retrospective multicenter study of consecutive case series was carried out during one year at nine departments of high-volume hospitals in Japan. The study included 325 consecutive patients (239 with peptic ulcers and 86 with artificial ulcers) with bleeding nonmalignant gastroduodenal ulcers that were revealed by emergency endoscopy between January 2008 and December 2008. Hemostasis was carried out mainly using endoscopic treatments. Rates of successful initial hemostasis, rebleeding, transfer to surgery, and death were recorded according to peptic and artificial ulcer bleeding. Additionally, preferred endoscopic methods, concomitant use of antisecretory drugs, and timing of second-look endoscopy were also measured. A total of 227 (99.1%) of 229 peptic ulcer patients with endoscopic treatment and all (100%) 84 artificial ulcer patients underwent successful tentative hemostasis. Rebleeding occurred in 23 peptic ulcer patients (10.1%) and 10 artificial ulcer patients (11.9%). One peptic ulcer patient and two artificial ulcer patients had final surgical rescue due to rebleeding. No death was observed. Monotherapy was predominant (around 65% of cases) in both types of ulcers. The coagulation forceps method was more frequently applied in artificial ulcers ( P < 0.05). A per oral proton pump inhibitor was more frequently used in artificial ulcers ( P < 0.05), although an intravenous proton pump inhibitor was used in the majority of patients in both types of ulcers. The frequency of second-look endoscopy in peptic ulcers (88%) was significantly higher than that in artificial ulcers (71%) ( P < 0.05). There seemed to be no rule as to the timing of second-look endoscopy, although it was most frequently performed on the day after hemostasis. The recent outcomes of endoscopic treatment for nonmalignant gastroduodenal bleeding in Japan were excellent in both peptic and artificial ulcers with similar efficacies. Although they were minor findings, some differences in applied endoscopic methods, concomitant use of antisecretory drugs, and presence of second-look endoscopy were observed. [ABSTRACT FROM AUTHOR]

Electrocautery forceps with soft coagulation are actively used for treatment of bleeding and nonbleeding visible vessels during endoscopic submucosal dissection, but the usefulness of gastroduodenal ulcer bleeding has not been elucidated so far. The purpose of this paper is to elucidate the outcomes of electrocautery forceps with soft coagulation for peptic and artificial gastroduodenal ulcer bleeding. A retrospective multicenter study of consecutive case series during one year involved nine departments of high-volume hospitals in Japan. The study included 128 consecutive patients (62 with peptic ulcers and 66 with artificial ulcers) with bleeding nonmalignant gastroduodenal ulcers that were revealed using emergency endoscopy between January 2008 and December 2008. Hemostasis was carried out using electrocautery forceps with soft coagulation. Rates of successful initial hemostasis, rebleeding, transfer to surgery, and death according to peptic and artificial ulcer bleeding were recorded. Successful initial endoscopic hemostasis was obtained in 61 peptic ulcer patients (98.4%) and 66 artificial ulcer patients (100%). Rebleeding was observed in seven peptic ulcer patients (11.5%) and five artificial ulcer patients (7.6%). Rates of successful management with endoscopic methods alone were 96.8% (60/62) and 100% (66/66) in peptic ulcer patients and artificial ulcer patients, respectively. There were no severe complications or deaths related to the management of gastroduodenal ulcer bleeding. The novel endoscopic method using electrocautery forceps with soft coagulation for gastroduodenal ulcer bleeding seems to provide safety and efficacy that is comparable with that of endoscopic hemostasis with other established hemostatic techniques. [ABSTRACT FROM AUTHOR]

Background: Our purpose was to evaluate the effectiveness of a newly developed non-invasive traction technique known as thin endoscope-assisted endoscopic submucosal dissection (TEA-ESD) procedure for the removal of colorectal laterally spreading tumors (LST). Patients and Methods: A total of 37 LST located in the rectum and distal sigmoid colons of 37 patients were eligible for outcome analysis. Twenty-one LST were treated with TEA-ESD and were then retrospectively compared to 16 LST that had previously been treated with standard ESD. Tumor size, en bloc resection rate, procedure time, combined number of different electrical surgical knives used during each procedure and associated complications were evaluated in this case–control study. Results: There was no statistically significant difference in tumor size between the TEA-ESD group and the ESD control group (43.6 ± 16 mm and 42.4 ± 14 mm, respectively). All LST were successfully resected en bloc in both groups. Procedure duration was shorter for the TEA-ESD group than the ESD control group, although the difference was not statistically significant (96 ± 53 minutes vs 116 ± 74 minutes; P = 0.18). The percentage of cases in which only one electrical surgical knife was used during the entire procedure was significantly higher in the TEA-ESD group compared to the ESD control group (85.7% vs 31.3%; P = 0.0005). There were no perforations in the TEA-ESD group while the ESD control group experienced one perforation. At the present time, TEA-ESD is limited to the rectum and distal sigmoid colon. Conclusion: It was technically easier, safer and more cost-effective to perform ESD for LST in the rectum and the distal sigmoid colon using the newly developed TEA-ESD traction technique. [ABSTRACT FROM AUTHOR]

Endoscopic submucosal dissection (ESD) can successfully resect early stage gastrointestinal tumors, but colorectal ESDs are not widely performed, even by Japanese endoscopists, because of several negative factors. Besides being considerably more difficult in terms of technical demands, colorectal ESDs involve a longer procedure time and have a higher complication rate compared to gastric ESDs. In addition, most colorectal lesions are adenomas or intramucosal cancers that despite their large size that can be curatively treated by endoscopic mucosal resection including piecemeal resection. There is, however, no doubt about ESD having a major therapeutic advantage in being able to achieve a higher en-bloc resection rate resulting in enhanced curability and more accurate histopathological assessment. Continued improvement in the technical skills of endoscopists, further refinement of such devices as electrical surgical knives and a special colonoscope as well as the development of more effective submucosal injection solutions and new traction systems are expected to facilitate easier, faster and safer colorectal ESD procedures in the relatively near future. [ABSTRACT FROM AUTHOR]

Background and Aim: Recent endoscopic imaging techniques for recognition of unclear lesions in the stomach (e.g. narrow band imaging, magnifying endoscopy) require special equipment and therefore are not commonly used. The aim of the present study was to estimate the accuracy of a new chromoendoscopic method using an acetic acid–indigo carmine mixture (AIM) in diagnosing early gastric cancers (EGC). Methods: Studied were 108 EGC lesions in 104 patients. EGC were initially observed by white light (WL) after which indigo carmine (IC) solution was sprinkled onto the gastric mucosa. Images by WL and IC observation were recorded by a digital filing system. After washing away IC solution with water, AIM solution was sprinkled onto the gastric mucosa and images were recorded. Margin lines of EGC determined by each observation were drawn on recorded images by graphic software for comparison with resected specimens. After lines were similarly drawn on images of resected specimens, the extent of the lesions was compared with that determined by endoscopic images. Results: Diagnostic accuracy of WL, IC, and AIM observations were 50.0%, 75.9% and 90.7%, respectively. No adverse events occurred with the AIM method. Conclusions: This chromoendoscopic method can be used to delineate the margin of EGC accurately, easily, safely and inexpensively. [ABSTRACT FROM AUTHOR]

Background and Aim Methods Results Conclusions As the population ages, the number of elderly patients with superficial esophageal squamous cell carcinoma (ESCC) is increasing. We aimed to clarify the indications for endoscopic resection (ER) in late‐elderly patients with ESCC in terms of life expectancy.Patients aged ≥75 years who underwent ER for ESCC at our institution from January 2005 to December 2018 were enrolled. Clinical data, including the Eastern Cooperative Oncology Group performance status, American Society of Anesthesiologists physical status (ASA‐PS), Charlson comorbidity index, and prognostic nutritional index (PNI), were collected at the time of ER. The main outcome measure was overall survival (OS).Two hundred eight consecutive patients were enrolled. The patients' median age was 78 years (range, 75–89 years). The 5‐year follow‐up rate was 88.5% (median follow‐up period, 6.6 years). The 5‐year OS rate was 79.2% (95% confidence interval [CI], 72.2–84.8), and 5‐year net survival standardized for age, sex, and calendar year was 1.04 (95% CI, 0.98–1.09). In the multivariate analysis, an ASA‐PS of 3 (hazard ratio, 2.45; 95% CI, 1.16–5.17) and PNI of <44.0 (hazard ratio, 2.73; 95% CI, 1.38–5.40) were independent prognostic factors. When neither of these factors was met, the 5‐year OS rate was 87.8% (95% CI, 80.0–92.9), and 5‐year net survival was 1.08 (95% CI, 1.02–1.14).ER for ESCC in late‐elderly patients may improve life expectancy. ER is recommended in patients with a good ASA‐PS and PNI. [ABSTRACT FROM AUTHOR]

En bloc resection is beneficial for accurate histological assessment of resected specimens of endoscopic mucosal resection. Conventional endoscopic mucosal resection is simple and convenient but with this procedure the size of specimen obtained from one-piece resection is very limited. Endoscopic submucosal dissection (ESD) using IT knife, Hook knife, Flex knife and so on has already been reported and it is useful to some expert endoscopists, but sometimes difficult for general endoscopists to use safely. The drawback of ESD is that it is difficult and is consequently associated with a higher rate of perforation, which may reach up to 2–6% . In addition, ESD requires advanced endoscopic techniques. Further improvement of devices and techniques is expected to be developed to prevent perforation for ESD procedure. [ABSTRACT FROM AUTHOR]