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Background/Aims: Accurately diagnosing diffuse gastric wall thickening is challenging. Hypertrophic gastritis (HG), while benign, mimics the morphology of Borrmann type 4 advanced gastric cancer (AGC B-4). We compared the features of endoscopy and endoscopic ultrasonography (EUS) between them. Methods: We retrospectively reviewed patients who underwent EUS for gastric wall thickening between 2000 and 2021, selecting HG and pathologically confirmed advanced gastric cancer cases. Ulceration and antral wall thickening were determined via endoscopy, while EUS assessed the 5-layered gastric wall structure, measuring the proper muscle (PM) layer and total wall thickness. Results: Male dominance was observed in AGC B-4, and the hemoglobin and albumin levels were significantly lower. The rate of antral wall thickening and presence of ulceration were significantly higher in AGC B-4 cases. Destruction of the PM layers was observed only in AGC B-4 cases, and the PM was significantly thicker in AGC B-4 cases. Forceps biopsy had an excellent success rate in ulcer-present AGC B-4 cases, but only a 42.6% success rate was observed for cases without ulcers, necessitating additional diagnostic modalities. A PM thickness of 2.39 mm distinguished between AGC B-4 and HG effectively. The multivariable analysis showed that a thickened PM layer and the presence of ulceration were significant risk factors for the diagnosis of AGC B-4. Conclusions: Endoscopic findings of a thickened gastric wall, including antral involvement, and presence of ulcer were significant risk factors for the diagnosis of AGC B-4. EUS findings of destroyed wall layers and a thickened PM of >2.39 mm were the key points of differentiation between HG and AGC B-4.

Background/Aims There is limited knowledge regarding the management of duodenal subepithelial lesions (SELs) owing to a lack of understanding of their natural course. This study aimed to assess the natural course of asymptomatic duodenal SELs and provide management recommendations. Methods Patients diagnosed with duodenal SELs and followed up for a minimum of 6 months were retrospectively investigated. Results Among the 443,533 patients who underwent esophagogastroduodenoscopy between 2008 and 2020, duodenal SELs were identified in 0.39% (1,713 patients). Among them, 396 duodenal SELs were monitored for a median period of 72.5 months (interquartile range, 37.7–111.3 mo). Of them, 16 SELs (4.0%) showed substantial changes in size or morphology at a median follow-up of 35.1 months (interquartile range, 21.7–51.4 mo). Of these SELs with substantial changes, tissues of two SELs were acquired using endoscopic ultrasound-guided fine needle aspiration biopsy: one was a lipoma and the other was non-diagnostic. Three SELs were surgically or endoscopically removed; two were diagnosed as gastrointestinal stromal tumors, and one was a lipoma. An initial size of 20 mm or larger was associated with substantial changes during follow-up (p = 0.016). Conclusions While the majority of duodenal SELs may not exhibit substantial interval changes, regular follow-up with endoscopy may be necessary for cases with an initial size of 20 mm or larger, considering a possibility of malignancy.

Background/Aims To overcome the technical limitations of classic endoscopic resection for gastric gastrointestinal stromal tumors (GISTs), various methods have been developed. In this study, we examined the role and feasibility of clip-and-cut procedures (clip-and-cut endoscopic full-thickness resection [cc-EFTR]) for gastric GISTs. Methods Medical records of 83 patients diagnosed with GISTs after endoscopic resection between 2005 and 2021 were retrospectively reviewed. Moreover, clinical characteristics and outcomes were analyzed. Results Endoscopic submucosal dissection (ESD) and cc-EFTR were performed in 51 and 32 patients, respectively. The GISTs were detected in the upper third of the stomach for ESD (52.9%) and cc-EFTR (90.6%). Within the cc-EFTR group, a majority of GISTs were located in the deep muscularis propria or serosal layer, accounting for 96.9%, as opposed to those in the ESD group (45.1%). The R0 resection rates were 51.0% and 84.4% in the ESD and cc-EFTR groups, respectively. Seven (8.4%) patients required surgical treatment (six patients underwent ESD and one underwent cc-EFTR,) due to residual tumor (n=5) and post-procedure adverse events (n=2). Patients undergoing R0 or R1 resection did not experience recurrence during a median 14-month follow-up period, except for one patient in the ESD group. Conclusions cc-EFTR displayed a high R0 resection rate; therefore, it is a safe and effective therapeutic option for small gastric GISTs.

Background Helicobacter pylori infection, prevalent in more than half of the global population, is associated with various gastrointestinal diseases, including peptic ulcers and gastric cancer. The effectiveness of early diagnosis and treatment in preventing gastric cancer highlights the need for improved diagnostic methods. This study aimed to develop a simple scoring system based on endoscopic findings to predict H. pylori infection. Methods A retrospective analysis was conducted on 1,007 patients who underwent upper gastrointestinal endoscopy at Asan Medical Center from January 2019 to December 2021. Exclusion criteria included prior H. pylori treatment, gastric surgery, or gastric malignancies. Diagnostic techniques included rapid urease and 13C-urea breath tests, H. pylori culture, and assessment of endoscopic features following the Kyoto gastritis classification. A new scoring system based on endoscopic findings including regular arrangement of collecting venules (RAC), nodularity, and diffuse or spotty redness was developed for predicting H. pylori infection, utilizing logistic regression analysis in the development set. Results The scoring system demonstrated high predictive accuracy for H. pylori infection in the validation set. Scores of 2 and 3 were associated with 96% and 99% infection risk, respectively. Additionally, there was a higher prevalence of diffuse redness and sticky mucus in cases where the initial H. pylori eradication treatment failed. Conclusions Our scoring system showed potential for improving diagnostic accuracy in H. pylori infection. H. pylori testing should be considered upon spotty redness, diffuse redness, nodularity, and RAC absence on endoscopic findings as determined by the predictive scoring system.

Duodenal mucosal resurfacing (DMR) by thermal ablation of the duodenal mucosa is a minimally invasive endoscopic procedure for controlling metabolic syndrome (MS). However, thermal energy can cause adverse effects due to deep mucosal injury, necessitating an additional mucosal lifting process, which complicate the procedures. Therefore, we aimed to develop a similar procedure using non-thermal photodynamic therapy (PDT) for DMR using a highly functional metal stent covered with photosensitizers (PSs) to minimize the potential risks of thermal ablation injury. We developed a novel PS stent enabling the controlled release of radical oxygen species with specific structures to prevent stent migration and duodenal stricture after ablation and performed an animal study (n = 8) to demonstrate the feasibility and safety of PDT for DMR. The stents were placed for 7 days to prevent duodenal strictures after PDT. To confirm PDT efficacy, we stained for gastric inhibitory polypeptide (GIP) and glucose transporter isoform 1. The PS stents were deployed, and PDT was applied without evidence of duodenal stricture, pancreatitis, or hemorrhage in any of the pigs. Microscopic evaluation indicated apoptosis of the mucosal cells in the irradiated duodenum on days 7 and 14, which recovered after day 28. Immunohistochemistry revealed suppressed GIP expression in the mucosal wall of the irradiated duodenum. Endoscopic PDT for DMR using PS stents could be applied safely in a porcine model and may result in decreased GIP secretion, which is a crucial mechanism in MS treatment. Further clinical studies are required to explore its safety and efficacy in patients with MS.

Background/Aims: H2 receptor antagonists (H2RA) have been used to treat gastritis by inhibiting gastric acid. Proton pump inhibitors (PPIs) are more potent acid suppressants than H2RA. However, the efficacy and safety of low-dose PPI for treating gastritis remain unclear. The aim was to investigate the efficacy and safety of low-dose PPI for treating gastritis. Methods: A double-blind, noninferiority, multicenter, phase 3 clinical trial randomly assigned 476 patients with endoscopic erosive gastritis to a group using esomeprazole 10 mg (DW1903) daily and a group using famotidine 20 mg (DW1903R1) daily for 2 weeks. The full-analysis set included 319 patients (DW1903, n=159; DW1903R1, n=160) and the per-protocol set included 298 patients (DW1903, n=147; DW1903R1, n=151). The primary endpoint (erosion improvement rate) and secondary endpoint (erosion and edema cure rates, improvement rates of hemorrhage, erythema, and symptoms) were assessed after the treatment. Adverse events were compared. Results: According to the full-analysis set, the erosion improvement rates in the DW1903 and DW1903R1 groups were 59.8% and 58.8%, respectively. According to the per-protocol analysis, the erosion improvement rates in the DW1903 and DW1903R1 groups were 61.9% and 59.6%, respectively. Secondary endpoints were not significantly different between two groups except that the hemorrhagic improvement rate was higher in DW1903 with statistical tendency. The number of adverse events were not statistically different. Conclusions: DW1903 of a low-dose PPI was not inferior to DW1903R1 of H2RA. Thus, lowdose PPI can be a novel option for treating gastritis (ClinicalTrials.gov Identifier: NCT05163756).

Background/objectives: Bismuth is commonly used in Helicobacter pylori (H. pylori) eradication therapy. However, few studies have examined the in vitro susceptibility of H. pylori to bismuth. Moreover, the exact mechanism of action of bismuth on H. pylori remains unclear. The aim of this study was to identify the anti-bacterial effect of bismuth as well as to evaluate potential synergistic effects between bismuth and various antibiotics. Methods: The minimum inhibitory concentrations (MICs) of three bismuth preparations, bismuth subsalicylate, bismuth potassium citrate, and colloidal bismuth subcitrate (CBS, De-Nol) were determined for H. pylori strains using the agar dilution technique. Agar plates of varying pH values from 5.0 to 8.0 were used to investigate whether acidity influences the anti-bacterial effect of bismuth. A checkerboard assay was performed to assess the synergism between CBS and antibiotics (amoxicillin, clarithromycin, and metronidazole). Results: Twelve H. pylori strains, including three reference strains (H. pylori 26695, J99, and ATCC 43504), and nine clinically isolated strains were tested. The MICs for bismuth subsalicylate, bismuth potassium citrate, and CBS ranged from 4 to 32 μg/mL, 2 to 16 μg/mL, and 1 to 8 μg/mL, respectively. The bismuth MICs for the reference strains were similar at pH 5–8. In the checkerboard assay, no interactions between CBS and any of the antibiotics were observed in the reference H. pylori strains. Conclusions: Bismuth showed in vitro susceptibility against H. pylori. The enhanced eradication efficacy of bismuth-containing regimens appears to be due to mechanisms other than direct synergy with antibiotics.

Abstract Background Proton-pump inhibitors (PPIs) are the most effective drugs for treating acid-related disorders. However, once-daily dosing with conventional PPIs fail to fully control acid secretion over 24 h. This study aimed to compare the efficacy and safety of HIP1601 (dual delayed-release esomeprazole) and HGP1705 (delayed-release esomeprazole) in patients with erosive esophagitis (EE). Methods We enrolled 213 patients with EE randomized in a 1:1 ratio to receive 40 mg HIP1601 (n = 107) or HGP1705 (n = 106) once daily for 4 or 8 weeks. The primary endpoint was the EE healing rate, confirmed by endoscopy up to week 8. GERD-related symptoms and treatment-emergent adverse events were compared between both groups. Results By week 8, the estimated healing rates of EE were 97.8% and 96.8% in the HIP1601 and HGP1705 groups, respectively, with a 95% confidence interval of -4.7 to 7.2. After 4 or 8 weeks of treatment, the EE healing rate at week 4, complete resolution rate of symptoms, time to sustained resolution of symptoms, and number of rescue medications used were similar in both groups. The proportion of heartburn- and acid regurgitation-free nights by week 4 were higher in the HIP1601 group compared to the HGP1705 group, but the difference did not reach clinical significance (87.7% vs. 85.8%, P = 0.514, 87.5% vs. 85.8%, P = 0.774). The number of adverse events did not differ significantly between the two groups. Conclusions The efficacy and safety of HIP1601 40 mg were comparable to those of HGP1705 40 mg for the treatment of EE and symptomatic improvement of GERD. Trial registration NCT04080726 ( https://classic.clinicaltrials.gov/ct2/show/NCT04080726 ), registration date: 25/10/2018.

Objectives The incidence of treatment failures following standard triple therapy (STT) for Helicobacter pylori eradication (HPE) has reached an unacceptable level. Sequential therapy (SQ) has emerged as a promising approach to counteract the escalation of antibiotic resistance. In this study, we used a chronological cohort dataset to conduct a comparative analysis of the eradication rates, compliance, and adverse events associated with the 7-day STT and SQ. Methods A total of 789 patients underwent HPE treatment at Asan Medical Center between July 2013 and August 2017. Among them, 378 received a 7-day STT and 411 received a 10-day SQ. Baseline clinical data and treatment parameters were compared between the two treatment groups. Results SQ demonstrated an eradication rate of 84.7% (348/411), which was superior to that of the 7-day STT (74.1%; p

Background/Aims: Although an association between achalasia and esophageal cancer has been reported, whether achalasia confers a substantial increase in mortality is unknown. Moreover, the causes of death related to achalasia have not been investigated. We performed this nationwide, population-based cohort study on achalasia because no such study has been performed since the introduction of high-resolution manometry in 2008. Methods: This study was performed using data extracted from the Korean National Health Insurance Service database, covering a 9-year period from 2009 to 2017. Control participants without a diagnostic code for achalasia were randomly selected and matched by sex and birth year at a case-to-control ratio of 1:4. Data on the cause of death from Statistics Korea were also analyzed. Results: The overall incidence of achalasia was 0.68 per 100,000 person-years, and the prevalence was 6.46 per 100,000 population. Patients with achalasia (n=3,063) had significantly higher adjusted hazard ratio (aHR) for esophageal cancer (aHR, 3.40; 95% confidence interval [CI], 1.25 to 9.22; p=0.017), pneumonia (aHR, 2.30; 95% CI, 1.89 to 2.81; p

Background/Aims: Fexuprazan is a novel potassium-competitive acid blocker that could be of benefit to patients with gastric mucosal injury. The aim of this study was to assess the 2-week efficacy and safety of fexuprazan in patients with acute or chronic gastritis.Methods: In this study, 327 patients with acute or chronic gastritis who had one or more gastric erosions on endoscopy and subjective symptoms were randomized into three groups receiving fexuprazan 20 mg once a day (q.d.), fexuprazan 10 mg twice a day (b.i.d.), or placebo for 2 weeks. The posttreatment assessments were the primary endpoint (erosion improvement rate), secondary endpoints (cure rates of erosion and edema and improvement rates of redness, hemorrhage, and subjective symptoms), and drug-related adverse events.Results: Among the patients, 57.8% (59/102), 65.7% (67/102), and 40.6% (39/96) showed erosion improvement 2 weeks after receiving fexuprazan 20 mg q.d., fexuprazan 10 mg b.i.d., and placebo, respectively. Both fexuprazan 20 mg q.d. and 10 mg b.i.d. showed superior efficacy to the placebo (p=0.017 and p

Background/Aims The treatment for gastric mucosa-associated lymphoid tissue lymphoma (MALToma) generally involves eradication of Helicobacter pylori. However, MALToma lesions may recur even without H. pylori re-infection. Furthermore, the remission rate of H. pylori-negative MALToma after eradication is low. Therefore, herein, we report on endoscopic submucosal dissection (ESD) as a treatment strategy for gastric MALToma. Methods We retrospectively reviewed the data of all patients of gastric MALToma who underwent endoscopic resection at our institution between January 2000 and December 2021. Clinical remission was defined as complete histological remission or probable minimal residual disease according to the GELA grading system for post-treatment evaluation of gastric MALToma. Results Six patients with gastric MALToma underwent ESD. Two patients were diagnosed with gastric MALToma, which improved after eradication treatment and relapsed approximately 36 and 41 months later, respectively. These patients had singular lesions localized to the mucosa and did not experience H. pylori re-infection. The lesions were successfully removed via ESD. The remaining four patients had H. pylori-negative gastric MALToma. These patients also had single, localized lesions that were removed via ESD. All the patients remained in clinical remission until the final follow-up. Conclusions ESD is a safe and effective intervention for H. pylori-negative gastric MALToma when the lesion is single and confined to the mucosal layer.

Background/Aims: Real-time polymerase chain reaction (RT-PCR) is a fast and simple method for the simultaneous detection of clarithromycin (CLR) resistance and Helicobacter pylori. We evaluated the effectiveness of RT-PCR compared to that of the rapid urease test (RUT) and assessed its value in verifying CLR resistance.Methods: A total of 70 specimens with confirmed H. pylori infection in culture were enrolled and analyzed in this prospective study. All specimens were subjected to RT-PCR assay using fluorescence melting peak signals to detect H. pylori infection and CLR resistances caused by either A2142G or A2143G mutations in the 23S ribosomal RNA gene (23S rRNA). The results were compared to those of RUT and antimicrobial susceptibility culturing tests to investigate the efficacy of RT-PCR.Results: Among the 70 specimens analyzed, the positivity rate was 97.1% (68/70) with RT-PCR and 82.9% (58/70) with RUT. CLR resistance (minimum inhibitory concentration >1.0 μg/mL) was confirmed in 18.6% (13/70), and fluorescence melting curve analysis showed that 84.6% (11/13) had point mutations in 23S rRNA. Ten specimens had only A2143G mutation, and one specimen contained both A2142G and A2143G mutations.Conclusions: RT-PCR assay was found to be more efficient than RUT in detecting H. pylori infection and could effectively verify CLR resistance compared to the antimicrobial susceptibility culturing test. Considering the high sensitivity and accessibility of RT-PCR method, it could be used to easily detect CLR-resistant H. pylori, thus helping clinicians select suitable treatment regimen and improve the eradication rate.

Background/Aims: Epstein-Barr virus (EBV) and Helicobacter pylori (HP) coinfection may synergistically induce severe inflammatory responses in the stomach tissue, increasing the risk of developing gastric cancer. We aimed to analyze the effect of EBV and HP coinfection on the clinicopathologic features and prognosis of gastric cancer, as well as to evaluate the role of EBV infection in non-gastric carcinoma with lymphoid stroma (non-GCLS).Methods: Overall, 956 patients who underwent surgery for gastric cancer between September 2014 and August 2015 were eligible and divided into groups, according to GCLS morphology, EBV infection, and HP infection. Clinicopathologic characteristics and oncologic outcomes were analyzed retrospectively.Results: EBV and HP coinfection was significantly associated with male sex, proximal location, GCLS morphology, and equivocal p53 expression (p

The apprenticeship-based training method (ABTM) is highly effective for gastrointestinal (GI) endoscopic training. However, the conventional ABTM has significant issues. Although many supplementary training methods (TMs) have been developed and utilized, they cannot entirely replace the ABTM, which remains the major TM strategy. Currently, new TM construction is crucial and necessary due to financial constraints, difficulty of obtaining sufficient training time due to patient safety-related regulations, and catastrophic damage caused by disasters such as the coronavirus disease 2019 pandemic. The simulator-based TM (SBTM) is widely accepted as an alternative to the ABTM, owing to the SBTM’s advantages. Since the 1960s, many GI endoscopy training simulators have been developed and numerous studies have been published on their effectiveness. While previous studies have focused on the simulator’s validity, this review focused on the accessibility of simulators that were introduced by the end of 2021. Although the current SBTM is effective in GI endoscopic education, extensive improvements are needed to replace the ABTM. Incorporating simulator-incorporated TMs into an improved ABTM is an attempt to overcome the incompleteness of the current SBTM. Until a new simulator is developed to replace the ABTM, it is desirable to operate a simulator-integrated and well-coordinated TM that is suitable for each country and institution.

A pyloric gland adenoma is a rare neoplasm that occurs most frequently in the stomach and should be removed because of its precancerous potential. Although there have been case reports of pyloric gland adenomas in extragastric areas such as the duodenum, pancreas, and bile duct, esophageal pyloric gland adenoma has never been reported in Korea. Herein, we report a case of esophageal pyloric gland adenoma that was successfully treated by endoscopic submucosal dissection.

Background/Aims The treatment of superficial esophageal neoplasms (SENs) in cirrhotic patients is challenging and rarely investigated. We evaluated the outcomes of endoscopic submucosal dissection (ESD) to determine the efficacy and safety of treating SENs in patients with liver cirrhosis. Methods The baseline characteristics and treatment outcomes of patients who underwent ESD for SENs between November 2005 and December 2017 were retrospectively reviewed. Results ESD was performed in 437 patients with 481 SENs, including 15 cirrhotic patients with 17 SENs. En bloc resection (88.2% vs. 97.0%) and curative resection (64.7% vs. 78.9%) rates were not different between the cirrhosis and non-cirrhosis groups (p=0.105 and p=0.224, respectively). Bleeding was more common in cirrhotic patients (p=0.054), and all cases were successfully controlled endoscopically. The median procedure and hospitalization duration did not differ between the groups. Overall survival was lower in cirrhotic patients (p=0.003), while disease-specific survival did not differ between the groups (p=0.85). Conclusions ESD could be a safe and effective treatment option for SENs in patients with cirrhosis. Detailed preprocedural assessments are needed, including determination of liver function, esophageal varix status, and remaining life expectancy, to identify patients who will obtain the greatest benefit.

Background/Aims The proposed eosinophilic esophagitis (EoE) endoscopic reference score serves to diagnose and evaluate treatment responses in EoE. Nevertheless, the validated reference score thresholds for diagnosis and treatment response in Asian patients are yet to be established. This study aims to establish these thresholds for the first time among Asian patients with EoE. Methods Patients presenting with ≥ 15 eosinophils/high power field and esophageal dysfunction symptoms between August 2007 and November 2021 were included. Age- and sex-matched non-EoE controls were also enrolled. Baseline characteristics, endoscopic reference score features, and scores were compared between patients and controls. Among patients, endoscopic reference score features and scores, along with peak eosinophil counts, were evaluated both before and after treatment. The optimal threshold was determined based on sensitivity, specificity, and the Youden index. Results Overall, 102 patients were enrolled (74.5% men; mean age, 46.9 years). The mean endoscopic reference score was 2.65 and 0.52 for patients and controls, respectively (P < 0.001). An endoscopic reference score ≥ 2 was identified as the optimal diagnostic threshold for EoE (sensitivity, 0.79; specificity, 0.86; Youden index, 0.66). Post-treatment data regarding endoscopic findings and histology were available for 30 patients. Regarding histologic response, an endoscopic reference score of ≤ 3 demonstrated the optimal threshold (sensitivity, 0.95; specificity, 0.88; Youden index, 0.83). Conclusions The optimal diagnostic and treatment response thresholds were determined to be endoscopic reference scores of ≥ 2 and ≤ 3, respectively. Further studies involving a larger patient cohort are necessary to validate these findings. [ABSTRACT FROM AUTHOR]

Background/Aims Chicago classification version 4.0 enhances the diagnosis of esophageal motility disorders using position change and provocative tests such as multiple rapid swallows and a rapid drink challenge. This study investigates the diagnostic role of the rapid drink challenge based on Chicago classification 4.0 using a functional luminal imaging probe to estimate the cutoff value. Methods This study included 570 patients who underwent esophageal manometry with a rapid drink challenge between January 2019 and October 2022. The diagnostic flow was analyzed according to Chicago classification 4.0. Results Ninety-nine patients (38, achalasia; 11, esophagogastric junction outflow obstruction; 7, ineffective esophageal motility; 1, hypercontractile esophagus; and 42, normal esophageal function) failed the rapid drink challenge. Among the 453 participants, 50 and 86 were diagnosed with achalasia and esophagogastric junction outflow obstruction, respectively, using Chicago classification 4.0. In 249/453 (55.0%) patients initially diagnosed with esophagogastric junction outflow obstruction using Chicago classification 3.0, the diagnosis was changed to achalasia (n = 28), hypercontractile esophagus (n = 7), ineffective esophageal motility (n = 7), or normal esophageal function (n = 121) using Chicago classification 4.0. Rapid drink challenge-integrated relaxation pressure’s diagnostic cutoff value was 19 mmHg. Nine patients had diagnoses changed after the rapid drink challenge, including 3 with panesophageal pressurization. Conclusions Chicago classification 4.0 increased the diagnostic yield of the rapid drink challenge by 2.0% (9/453 patients). However, the rapid drink challenge had a failure rate of 17.9% (99/552 patients). Given the relatively low diagnostic yield and high failure rate of the rapid drink challenge, we recommend adopting an individualized approach to manometry [ABSTRACT FROM AUTHOR]

Background/Aims: Postprocedural bleeding is known to be relatively low after argon plasma coagulation (APC) for gastric neoplasms; however, there are few studies proving the effect of antithrombotic agents. This study aimed to analyze the incidence of delayed bleeding (DB) based on antithrombotic agents administered and to identify the risk factors for DB in APC for gastric tumors. Methods: A total of 785 patients with 824 lesions underwent APC for single gastric neoplasm between January 2011 and January 2018. After exclusion, 719 and 102 lesions were classified as belonging to the non-antithrombotics (non-AT) and AT groups, respectively. The clinical outcomes were compared between the two groups, and we determined the risk factors for DB in gastric APC. Results: Of the total 821 cases, DB occurred in 20 cases (2.4%): 17 cases in the non-AT group and three cases in the AT group (2.4% vs 2.9%, p=0.728). Multivariate analysis of the risk factors for DB confirmed the following significant, independent risk factors: male sex (odds ratio, 7.66; 95% confidence interval, 1.02 to 57.69; p=0.048) and chronic kidney disease (odds ratio, 4.51; 95% confidence interval, 1.57 to 13.02; p=0.005). Thromboembolic events and perforation were not observed in all patients regardless of whether they took AT agents. Conclusions: AT therapy is acceptably safe in gastric APC because it does not significantly increase the incidence of DB. However, patients with chronic kidney disease or male sex need to receive careful follow-up on the incidence of post-APC bleeding.

Abstract Background Ingested foreign objects frequently require emergency removal. This study aimed to investigate the clinical outcomes of endoscopic removal of foreign bodies from the upper gastrointestinal tract and the risk factors for adverse events. Methods Adults (> 18 years) who underwent endoscopic management of ingested foreign bodies at two centers, one inland and one on the coast, between January 2008 and December 2017 were eligible. Clinical characteristics and procedure-related outcomes were retrospectively reviewed. Patients were divided into two groups, based on whether the foreign bodies were sharp or blunt in shape. Results A total of 853 patients aged 19–96 years were analyzed. Ingestion of fish bones was more common in the coastal area, whereas ingestion of food boluses was more common in the inland area. The duration of impaction ranged from 1 h to over 1 month and was significantly longer in patients who ingested blunt than sharp foreign bodies (15 vs. 5 h, p

Background/Aims: Data regarding the prognosis of early esophageal cancer are lacking. This study investigated the long-term outcomes and factors affecting the survival of patients with mucosal esophageal squamous cell carcinoma (T1aESCC). Methods: We analyzed the clinical and tumor-specific parameters of 263 patients who received surgical resection (SR; n=63) or endoscopic resection (ER; n=200) for T1aESCC. Underlying comorbidities were scored using the Charlson comorbidity index (CCI). Overall survival (OS) was the primary outcome, and multivariate regression analysis was performed to predict factors for OS. Results: Of the study patients (age, 64.5±8.0 years), the CCI was 1.0±1.4 in the ER group and 0.6±0.9 in the SR group (p=0.107). The 5-year OS rate during follow-up (54.4±20.4 months) was 85.7% (ER group, 86.8%; SR group, 82.4%; p=0.631). The cumulative 5-year incidence of esophageal cancer recurrence was 10.5% in the ER group (vs 0% in the SR group). The overall mortality rate was 12.9% (ER group, 12.0%; SR group, 15.9%; p=0.399). The most common cause of mortality was second primary cancers in the ER group (75%) and organ dysfunction or postoperative complications in the SR group (70%). According to multivariate analysis, only CCI was significantly associated with OS (p2 and in those with a CCI ≤2 was 60.2% and 88.2%, respectively (p

Background/Aims: The incidence of peptic ulcer disease has decreased in past decades; however, the trends in peptic ulcer bleeding (PUB) are inconsistent among regions. This study aimed to investigate the trends in PUB incidence and the effect of risk factors on PUB in Korea. Methods: The records of patients hospitalized with PUB from 2006 to 2015 were retrieved from the Korean National Health Insurance Service Database. Standardized incidences of PUB were calculated, and the clinical characteristics such as age, sex, Helicobacter pylori infection, drug exposure, comorbidities, and mortality were obtained. Results: In total, 151,507 hospitalizations with PUB were identified. The overall annual hospitalization rate was 34.98 per 100,000 person-years. The incidence of PUB showed no significant change from 2006 to 2008 and decreased from 2008 to 2015, with an annual change of -2.7% (p

Background/Aims The learning curve is essential in endoscopic submucosal dissection (ESD) training to improve outcomes and reduce the risk of procedure-related complications. We compared the outcomes of gastric ESD in live pigs performed by inexperienced endoscopists with or without ex vivo training. Materials and Methods At the Olympus Medical Training and Education Center, nine endoscopists inexperienced in ESD were randomly divided into two groups (group A: ex vivo training followed by in vivo training; group B: in vivo training only), and they performed gastric ESDs. Results A total of 18 ESDs were performed. The en bloc resection rate was 88.9% (16/18), and the complete resection rate was 94.4% (17/18). The median specimen size was 2.5 cm in group A and 2.1 cm in group B (P=0.227). There was no significant difference in the procedure time between the two groups, except for the marking time (0′58″ vs. 2′58″, P=0.027). However, group A took a shorter time in dissecting the same area than group B (109 vs. 246 sec/cm2, P=0.083). Complication rates were not significantly different between both groups. Conclusions The procedure time during in vivo ESD training in pigs may be shortened by prior ex vivo training. However, the ex vivo model presented poor air inflation, unstable fixation, and excessive mucosal hardness for cutting. An advanced simulator or sufficient ex vivo training may be effective in training for the ESD procedure.

Abstract As patients receiving definitive chemoradiotherapy (dCRT) for oesophageal squamous cell carcinoma (ESCC) are heterogeneous, we aimed to identify prognostic factors and failure patterns after dCRT. From 2006 to 2015, 327 patients who received dCRT for ESCC were reviewed. Treatment response to dCRT was evaluated based on EORTC‐PET criteria with endoscopy and CT results. After dCRT, 296 patients (90.5%) achieved disease stabilisation, with 132 cases of complete response (CR) (40.4%), 158 of partial response (PR) (48.3%) and 6 of stable disease (SD) (1.8%); 31 patients (9.5%) had progressive disease (PD). Median overall survival (OS) from response evaluation was 24.0 months in the overall population. Post‐treatment clinical response was the most significant prognostic factor for OS in the multivariate analysis (median OS, 65.0 months for CR, 17.3 months for PR, 4.4 months for SD and 4.0 months for PD; p

Abstract We aimed to investigate the endoscopic features and clinical course of CMV gastroenterocolitis in immunocompetent patients. We reviewed the medical records and endoscopic images of 86 immunocompetent patients with CMV gastroenterocolitis. Immunocompetent patients were defined as those without congenital or acquired immunodeficiency syndrome, use of anti-cancer chemotherapeutic and immunosuppressive agents, and inflammatory bowel diseases. The mean age was 65.5 ± 11.8 years and 53 (61.6%) were male. Sixty-eight (79.1%) patients had comorbidities. Upper gastrointestinal-dominant, small bowel-dominant, and colon-dominant types were observed in 19, 7, and 60 patients, respectively. Endoscopic features could be classified into discrete ulcerative type with/without exudate and diffuse erythematous type with/without exudate. Antiviral treatment with ganciclovir was initiated in 51 patients (59.3%), 40 of whom improved and 1 improved after changing ganciclovir to foscarnet. Thirty-three patients (38.4%) improved without antiviral treatment. Surgery was necessary in two patients because of colon perforation before antiviral treatment. Another two patients underwent surgery because of sigmoid stricture and cecal perforation during antiviral treatment. Endoscopic type was not associated with clinical outcomes, such as surgery and death. CMV gastroenterocolitis in immunocompetent patients mostly occur in older patients with comorbidities, and the endoscopic features vary with no association with clinical outcomes.

Abstract The endoscopic features between herpes simplex virus (HSV) and cytomegalovirus (CMV) esophagitis overlap significantly, and hence the differential diagnosis between HSV and CMV esophagitis is sometimes difficult. Therefore, we developed a machine-learning-based classifier to discriminate between CMV and HSV esophagitis. We analyzed 87 patients with HSV esophagitis and 63 patients with CMV esophagitis and developed a machine-learning-based artificial intelligence (AI) system using a total of 666 endoscopic images with HSV esophagitis and 416 endoscopic images with CMV esophagitis. In the five repeated five-fold cross-validations based on the hue–saturation–brightness color model, logistic regression with a least absolute shrinkage and selection operation showed the best performance (sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the receiver operating characteristic curve: 100%, 100%, 100%, 100%, 100%, and 1.0, respectively). Previous history of transplantation was included in classifiers as a clinical factor; the lower the performance of these classifiers, the greater the effect of including this clinical factor. Our machine-learning-based AI system for differential diagnosis between HSV and CMV esophagitis showed high accuracy, which could help clinicians with diagnoses.

Background/Aims Percutaneous endoscopic gastrostomy (PEG) is usually performed on patients with chronic underlying diseases in the general ward (GW). This study evaluated the clinical outcomes of PEG performed on patients in the surgical intensive care unit (SICU) compared with those of PEG performed in the GW. Methods The medical records of 27 patients in the SICU and 263 in the GW, who underwent PEG between January 2013 and July 2017, were retrospectively reviewed. Results The median age of the 27 SICU patients was 66 years, and their median body mass index was 21.1 kg/m2. In the SICU group, the median baseline Sequential Organ Failure Assessment (SOFA) score was 4, and the median Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 16. The median interval between surgery and PEG in SICU patients was 30 days, with a PEG failure rate of 3.7%. Acute complications in SICU patients included bleeding (7.4%) and ileus (11.1%), while chronic complications included aspiration pneumonia (7.4%) and tube obstruction (3.7%). The rates of acute and chronic complications did not differ significantly between the SICU and GW groups. The 30-day mortality rate was 14.8% in SICU patients and 5.3% in GW patients (p=0.073). Conclusions PEG is a safe and feasible method of enteral feeding for critically ill patients who require ICU care after surgery.

Superficial esophageal neoplasms (SENs) are being diagnosed increasingly frequently due to the screening endoscopy and advances in endoscopic techniques. Endoscopic resec-tion (ER) is a relatively noninvasive treatment method with low morbidity and mortality that provides excellent oncologic outcomes. Endoscopic submucosal dissection is asso-ciated with higher rates of en bloc, complete and curative resections and lower rates of local recurrence than endoscopic mucosal resection. The most serious complication of ER is stricture, the treatment and prevention of which are crucial to maintain the patient’s quality of life. ER for SEN is feasible, effective, and safe and can be considered a first-line treatment for SENs in which it is technically feasible.

Abstract Background The association between Helicobacter pylori and reflux esophagitis (RE) remains controversial. This study aimed to prospectively evaluate the effect of H. pylori eradication on RE and gastroesophageal reflux (GERD) symptoms in H. pylori-positive patients who underwent endoscopic resection of gastric neoplasm. Methods Of the 244 patients enrolled in this study, 173 H. pylori-positive patients underwent follow-up at least once. We evaluated the prevalence of RE and GERD symptoms in these patients following H. pylori eradication. Results There were 75.7% (131/173), 78.6% (125/159), and 78.9% (105/133) subjects who were successfully eradicated after 6, 12, and 18–24 months, respectively. During the 2-year follow-up period, the eradication of H. pylori did not increase the incidence of RE (OR 0.93; 95% CI, 0.49–1.77, p = 0.828). H. pylori status was also not associated with the development of GERD symptoms (OR 1.12; 95% CI, 0.47–2.95, p = 0.721). In the univariate analysis for RE, present smoking history (OR 4.79; 95% CI 1.98–11.60, p = 0.001), present alcohol consumption history (OR 2.18; 95% CI 1.03–4.63, p = 0.041), and diabetes mellitus (OR 2.44; 95% CI 1.02–5.86, p = 0.045) were found to be associated with RE. Multivariate analysis showed that present smoking history (OR 4.54; 95% CI 1.84–11.02, p = 0.001) was a significant risk factor for RE. Conclusions H. pylori eradication did not increase the incidence of RE or GERD symptoms in patients who underwent endoscopic resection of gastric neoplasm.

Background/Aims This study was aimed to investigate the current clinical status of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) in Korea based on a National Health Insurance (NHI) database between 2011 and 2014. Methods The claims data of ESD for EGC in Korean NHI were reviewed using material codes of Health Insurance Review and Assessment Service between November 2011 and December 2014. The current clinical status was analyzed in terms of treatment pattern, in-hospital length of stay (LOS), total medical costs, and en bloc resection rate according to the hospital type. Results A total of 23,828 cases of ESD for EGC were evaluated. ESD was performed in 67.4% of cases in tertiary care hospitals, 31.8% in general hospitals, and 0.8% in hospitals, respectively. The median LOS was 5 days, and total median medical costs was approximately 1,300 US dollars. En bloc resection rate was 99%; 8.5% of cases underwent additional treatment within 90 days ESD, and 5.5% in 91 to 365 days after ESD. The clinical status was not significantly different according to the year and hospital type. Conclusions A majority of ESD for EGC were performed in tertiary care hospitals in Korea. The clinical status showed excellent clinical outcomes and did not differ by the year and between the types of hospitals in Korea.

Summary: Background: Laparoscopic antireflux surgery is a standard surgical treatment method for gastroesophageal reflux disease (GERD) in Western countries. However, the procedure has not been actively carried out in Korea because of concerns regarding surgical complications. Here, we conducted this study to evaluate short-term surgical outcomes of laparoscopic Nissen fundoplication (LNF) performed at a single institution. Methods: From January 2010 to August 2016, totally 29 patients underwent LNF for GERD performed by three surgeons at Asan Medical Center, Korea. All patients participated in a telephonic survey including the presence of symptoms and the status of quality of life (QOL). Results: The median age at operation and BMI were 54 years and 23.8 kg/m2, respectively. Preoperatively, 27 patients (93.1%) underwent PPI therapy. All patients had typical or atypical GERD symptoms. One patient (3.4%) required reoperation because of total gastroesophageal junction obstruction. 24 patients (82.8%) reported complete or partial resolution of symptoms, whereas 21 (72.4%) reported partial or complete improvement in quality of life. In patients with reflux esophagitis, GERD symptoms were significantly relieved after LNF (P = 0.005). LNF responders tended to perceive an improvement in quality of life post operation (P

Using data from the real world to solve clinical questions that cannot be answered using data from clinical trials is attracting more attention. Clinical outcomes for patients with esophageal cancer in a real-world setting might be different from data in randomized controlled trials. This study aimed to provide real world data on treatment and prognosis in Korean patients with esophageal cancer. This retrospective cancer cohort included newly diagnosed cases of esophageal cancer at 19 tertiary hospitals between January 1, 2005 and December 31, 2017. Cancer staging was defined according to the 7th edition of the American Joint Committee on Cancer criteria. We identified 6,354 patients with newly diagnosed esophageal cancer (mean age: 64.9 ± 9.0 years, 96.9% squamous cell carcinoma). The proportion of early esophageal cancer increased from 24.7% in 2005 to 37.2% in 2015 (p

BACKGROUND:Although endoscopic submucosal dissection (ESD) is widely used, the current status and trend in its training have yet to be fully evaluated. We aimed to investigate how ESD endoscopists have been trained in actual clinical practice. METHODS:Endoscopists aged

Background/AimsTo evaluate the efficacy and safety of a controlled release, once-daily formulation of mosapride (UI05MSP015CT) in patients with functional dyspepsia (FD).Methods : Patients with FD were randomly assigned (1:1) to receive either UI05MSP015CT (15 mg once a day, study group) or mosapride (5 mg three times a day, control group) and corresponding placebo for 4 weeks. The primary endpoint was a change in the gastrointestinal symptom score (GIS) evaluated at enrollment and after 4 weeks. Secondary endpoints were changes in the Nepean Dyspepsia Index-Korean version (NDI-K), rate of satisfactory symptom relief, and rate of adverse events.Results : A total of 138 patients were enrolled (female, 73.9%; mean age, 44.0±15.4 years). After excluding patients who violated the study protocol, 59 and 58 patients from the study and control groups, respectively, were included in the per-protocol analysis. No difference was observed in drug compliance between the control and study groups (97.07%±4.52% vs 96.85%±6.05%, p=0.870). Changes in GIS scores were 9.69±6.44 and 10.01±5.92 in the study and control groups. The mean difference in GIS change between groups was 0.33 (95% confidence interval, 1.75 to 2.41), demonstrating non-inferiority of UI-05MSP015CT (p=0.755). The rate of satisfactory symptom relief was not different between the study and control groups (39.0% vs 56.9%, p=0.053). No differences in change in NDI-K score (14.3 vs 16.9, p=0.263) or rates of adverse events (12.9% vs. 4.4%, p=0.062) were observed between the study and control groups.Conclusion : sOnce-daily mosapride is not inferior to conventional mosapride in efficacy and is safe in patients with FD.

Background/Aims To report the long-term survival and tumor recurrence outcomes in patients with superficial esophageal cancer (SEC) after complete non-curative endoscopic resection (ER). Methods We retrieved ER data for 24 patients with non-curatively resected SEC. Non-curative resection was defined as the presence of submucosal and/or lymphovascular invasion on ER pathology. Relevant clinical and tumor-specific parameters were reviewed. Results The mean age of the 24 study patients was 66.3±8.3 years. Ten patients were closely followed up without treatment, while 14 received additional treatment. During a mean follow-up of 59.0±33.2 months, the 3- and 5-year survival rates of all cases were 90.7% and 77.6%, respectively. The 5-year overall survival rates were 72.9% in the close observation group and 82.1% in the additional treatment group (p=0.958). The 5-year cumulative incidences of all cases of recurrence (25.0% vs. 43.3%, p=0.388), primary EC recurrence (10.0% vs. 16.4%, p=0.558), and metachronous EC recurrence (16.7% vs. 26.7%, p=0.667) were similar between the two groups. Conclusions Patients with non-curatively resected SEC showed good long-term survival outcomes. Given the similar oncologic outcomes, close observation may be an option with appropriate caution taken for patients who are medically unfit to receive additional therapy.

Background/Aims: We aimed to compare the outcomes of Helicobacter pylori eradication in patients receiving sequential therapy (ST) depending on the use of ecabet sodium (ES). Materials and Methods : Between January to December 2015, 176 patients randomly received either ST alone (n=72) or 10-day ES therapy combined with ST (n=104). After applying the exclusion criteria, 56 patients were finally assigned to the ST-only group and 84 to the ST with ES group. We retrospectively reviewed and analyzed the H. pylori eradication rate and adverse events between the two groups. Results : Among the 140 patients, 121 (86.4%) achieved successful H. pylori eradication and 24 (17.1%) had adverse events. Eradication was achieved in 50 patients (89.3%) in the ST-only group and in 71 patients (84.5%) in the ST with ES group (P=0.420). No significant difference in the incidence of adverse events was found between the ST-only and ST with ES groups (12.5% vs. 20.2%, respectively; P=0.234). However, the ST with ES group tended to have a higher prevalence of nausea or vomiting than the ST-only group (11.9% vs. 1.8%; P=0.050). Conclusions : ST showed a good H. pylori eradication rate without deteriorating the adverse events regardless of adding ES.

Background/AimsEndoscopic submucosal dissection (ESD) has been regarded as a curative treatment for early gastric cancer (EGC) in indicated cases. The aim of this study was to evaluate the nationwide long-term clinical outcomes of ESD for EGC in Korea.Methods : A prospective multicenter cohort study was performed to evaluate the long-term efficacy of ESD for EGC within pre-defined indications at 12 institutes in Korea. The cases that met the expanded criteria upon pathological review after ESD were followed for 5 years. The primary outcome was 5-year disease specific free survival.Results : Six hundred ninety-seven patients with 722 EGCs treated with ESD were prospectively enrolled and followed for 5 years. Complete resection was achieved in 81.3% of the cases, and curative resection was achieved in 86.1%. During the 5-year follow-up, the overall survival rate was 96.6%, and the disease specific free survival rate was 90.6%. Local recurrence developed in 0.9%, and metachronous tumor development occurred in 7.8%; both conditions were treated by endoscopic or surgical treatment. Distant metastasis developed in 0.5% during follow-up.Conclusion : sESD showed excellent long-term clinical outcomes and can be accepted as a curative treatment for patients with EGC who meet the expanded criteria in final pathology studies.

Abstract Background Percutaneous endoscopic gastrostomy (PEG) is a relatively safe procedure; however, acute and chronic complications of PEG have been reported. We aimed to determine risk factors associated with complications and 30-day mortality after PEG, based on 11 years of experience at a single tertiary hospital. Methods In total, 401 patients who underwent first PEG insertion at the Asan Medical Center, Seoul, Korea, between January 2005 and December 2015 were eligible. Medical records were retrospectively reviewed to determine clinical characteristics and outcomes of 139 and 262 patients who underwent pull-type and introducer-type PEG, respectively. Results The median age of the overall population was 68 years, and the median body mass index was 19.5 kg/m2. Acute and chronic complications developed in 96 (23.9%) and 105 (26.2%) patients. Acute ileus and chronic tube obstruction were significantly more frequent in the introducer-type PEG group (p = 0.033 and 0.001, respectively). The 30-day mortality rate was 5.0% (median survival: 10.5 days). Multivariate analysis revealed that underlying malignancy was a predictor of acute complications; age ≥ 70 years and diabetes mellitus were predictors of chronic complications. The median follow-up was 354 days. Neurologic disease and malignancy were the most common indications for PEG. Neurologic diseases were classified into two groups: stroke and the other neurologic disease group (including dementia, Parkinson’s disease, neuromuscular disease, and hypoxic brain damage). Multivariate analysis showed that 30-day mortality was significantly lower in the other neurologic disease group and higher in patients with platelet count

Background/AimsWe aimed to investigate whether the current indications for curative endoscopic resection (ER) of gastric cancer (GC) can be applied to GC caused by adenoma. Additionally, we attempted to identify factors predictive of lesions subsequently found in addition to the expanded indications for ER.Methods : We retrospectively analyzed 342 patients diagnosed with GC caused by adenoma who underwent ER at a single tertiary center between February 2011 and December 2014. The gross whole tumor size was measured using the endoscopically resected specimen. The microscopic whole tumor size was measured using mapping paper. The estimated cancer size was calculated using the microscopic whole tumor size and the square root of the carcinoma component.Results : A gross whole tumor size ≥3 cm, carcinoma component ≥35%, and gross ulceration were predictive of lesions other than the expanded indications for ER. The overall rate of lymph node metastasis was 0.3% (1/327), which only occurred in one patient with a lesion other than the expanded indications (4.5%, 1/22).Conclusion : sThe current indications for curative ER in GC can be applied to GC caused by adenoma. In cases suspected of having lesions other than the expanded indications, patients should be cautiously selected for ER to reduce the risk of an inappropriate procedure.

Background/AimsWe used three-dimensional (3D) printing technology to create a new biopsy simulator for the stomach and investigated its efficacy and realism in endoscopic biopsy training.Methods : A novel stomach biopsy simulator, with 10 biopsy sites, was produced using a 3D printer. We enrolled 26 participants, including 10 residents, six first-year fellows, five second-year fellows, and five faculty members. We recorded and reviewed five training sessions and evaluated the simulator with questionnaires using a 7-point Likert scale.Results : The mean completion time (seconds) was 244.8±11.5 for the residents, 107.9±33.4 for the first-year fellows, 106.8±20.1 for the second-year fellows, and 103.8±19.2 for the faculty members. The completion time became shorter with repetition and was significantly lower for residents by the fifth trial (first trial, 347.0±159.5; fifth trial, 169.6±57.7; p=0.007). The faculty members strongly agreed that the simulator realistically reflected endoscopic handling and was reasonable for endoscopic training (scores of 6.2±0.8 and 6.4±0.9, respectively). Importantly, experienced endoscopists reported that the difficulty levels of the 10 biopsy sites in the simulator were a realistic match for the actual stomach.Conclusion : sThis endoscopic biopsy simulator created using a 3D printer is a realistic and useful method to improve the biopsy skills of trainee endoscopists.

A gastrocolocutaneous fistula is a rare complication of percutaneous endoscopic gastrostomy (PEG). We report a case of a gastrocolocutaneous fistula presenting with intractable diarrhea and gastrostomy tube malfunction. A 62-year-old woman with a history of multiple system atrophy was referred to us because of PEG tube malfunction. Twenty days prior to presentation, the patient started developing sudden diarrhea within minutes after starting PEG feeding. Fluoroscopy revealed that the balloon of the PEG tube was located in the lumen of the transverse colon with the contrast material filling the colon. Subsequently, the PEG tube was removed and the opening of the gastric site was endoscopically closed using hemoclips. Clinicians should be aware of gastrocolocutaneous fistula as one of the complications of PEG insertion. Sudden onset of diarrhea, immediately after PEG feedings, might suggest this complication, which can be effectively treated with endoscopic closure.

Background/Aims: We aimed to compare the outcomes and timing of Helicobacter pylori eradication in patients with iatrogenic and peptic ulcers. Materials and Methods: This was a retrospective study of 183 patients treated between 2012 and 2015 with 7-day standard triple therapy after endoscopic resection (ER). The patients were enrolled as the iatrogenic ulcer group and assigned to an early treatment group (n=139, H. pylori eradication initiated 2 days after ER) and a late treatment group (n=44, 8 weeks after ER). During the same period, 152 patients with peptic ulcer were assigned to the peptic ulcer group. Results: Successful H. pylori eradication was achieved in 141 patients (77.0%) in the iatrogenic ulcer group and 114 (75.0%) in the peptic ulcer group (P=0.661). Among the ER patients, the eradication rate was 79.9% (n=111) in the early treatment group and 68.2% (n=30) in the late treatment group (P=0.109). The adverse event rate was significantly higher in the peptic ulcer group than in the iatrogenic ulcer group (13.8% vs. 4.9%, P=0.005). Compliance and adverse events did not significantly differ between the early and late treatment groups. Conclusions: In iatrogenic ulcer, H. pylori eradication can be performed with a relatively lower adverse event rate, regardless of treatment timing, than that in peptic ulcer.