Prognostic Impact of Inflammation-Based Factors in Patients with Esophageal Squamous Cell Carcinoma Achieving Pathological Complete Response After Neoadjuvant Chemoradiotherapy Followed by Surgery.

BACKGROUND: Patients achieving pathological complete response (pCR) post-neoadjuvant chemoradiotherapy (nCRT) and surgery for locally advanced esophageal squamous cell carcinoma (ESCC) have a favorable prognosis. However, recurrence occurs in approximately 20-30% of all patients, with few studies evaluating their prognostic factors. We identified these prognostic factors, including inflammation-based markers, in patients with ESCC showing pCR after nCRT and surgery. PATIENTS AND METHODS: Patients with ESCC undergoing esophagectomy post-nCRT (January 2007-August 2017) were studied. Survival analysis evaluated 5-year overall (OS) and recurrence-free survival (RFS). Risk factors, including inflammation factors, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio (PLR), were analyzed using Cox-proportional hazards model. RESULTS: Overall, 123patients participated herein. After a median follow-up duration of 67 months (44-86 months), 17 patients (12.3%) had recurrent disease. The 5-year OS and RFS rates were 71.6% and 68.0%, respectively. In the multivariable analysis, older age ( ≥ 60 years) [hazard ratio (HR) 3.228, 95% confidence interval (CI) 1.478-7.048, p = 0.003], higher pretreatment T stage (≥ T3; HR 2.563, 95% CI 1.335-4.922, p = 0.005), nonapplication of induction chemotherapy (HR 2.389, 95% CI 1.184-4.824, p = 0.015), and higher post-nCRT PLR (≥ 184.2; HR 2.896, 95% CI 1.547-5.420, p = 0.001) were poor independent prognostic factors for 5-year RFS. The patient group with three to four identified factors with poor outcomes exhibited a 5-year RFS rate of 46.2%. CONCLUSIONS: Significant prognostic factors include higher post-nCRT PLR, older age, higher clinical T stage, and nonapplication of induction chemotherapy. Identifying higher recurrence risk patients is crucial for tailored follow-up and treatment.

Clinical course of asymptomatic duodenal subepithelial lesions.

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). CONCLUSION: 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.

Association of local steroid injection as a risk factor for electrocoagulation syndrome after esophageal endoscopic submucosal dissection.

BACKGROUND: Postendoscopic submucosal dissection electrocoagulation syndrome (PEECS) is commonly observed after performing endoscopic submucosal dissection (ESD) for esophageal neoplasia. However, data on the incidence and risk factors for PEECS in the esophagus are lacking due to an unclear definition of PEECS and varied clinical settings. Therefore, we aimed to determine the risk factors for PEECS in patients undergoing ESD for esophageal neoplasia. METHODS: We retrospectively reviewed data of relevant clinical and endoscopy-specific parameters from 202 consecutive patients with esophageal neoplasias (139 carcinomas and 63 dysplasias) who underwent ESD under general anesthesia. Esophageal PEECS was defined by satisfying at least two of the following criteria: fever ≥ 37.8 °C, leukocytosis ≥ 10,800/mm3, and localized chest pain ≥ 5/10 points as assessed on a numeric rating scale within 24 h after ESD. Significant factors associated with PEECS were determined by regression analysis. RESULTS: PEECS was recorded in 98 of 202 (48.5%) patients. Patients with PEECS exhibited a larger tumor size (25.0 vs. 17.0 mm, P = 0.002), longer procedure (40.0 vs. 29.5 min, P = 0.021) and hemostasis times (5.0 vs. 3.5 min, P = 0.004), required greater submucosal injection volume (60.0 mL vs. 50.0 mL, P = 0.030), and had a lower rate of local steroid injection (4.1% vs. 12.5%, P = 0.029) than those without PEECS. Multivariate regression analysis revealed tumor size ≥ 17 mm (P = 0.047), procedure time ≥ 33 min (P = 0.027), and hemostasis time ≥ 5 min (P = 0.007) as risk factors for PEECS. In addition, local steroid injection was a significant negatively associated factor (P = 0.001). CONCLUSIONS: Patients with a large tumor, prolonged procedure and hemostasis times are at a high risk of PEECS occurrence. Further, local steroid injection is a negatively associated factor.

Predicting Helicobacter pylori infection from endoscopic features.

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. CONCLUSION: 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.

Natural history of gastric leiomyoma.

BACKGROUND: Most gastric leiomyomas are asymptomatic and benign subepithelial tumors (SETs); however, some may increase in size or become symptomatic. Understanding their natural history is therefore important to their management. We investigated the natural history of histologically proven gastric leiomyomas. METHODS: We retrospectively reviewed histologically proven gastric leiomyoma cases at a tertiary center. The baseline characteristics of these cases were analyzed, and those with a follow-up period of at least 12 months without immediate resection were evaluated. The primary outcome was the frequency of size increase of more than 25% during the follow-up period, and the secondary outcome was the histopathologic results in cases that underwent resection. RESULTS: Among the 231 patients with histologically proven gastric leiomyomas, the most frequent location was the cardia (77.1%), and the median size was 3 cm (IQR 2-4 cm). Eighty-four cases were followed up over a median period of 50.8 months (IQR 27.2-91.3 months). During the follow-up period, tumor size increased in two cases (2.4%). Surgical results showed that one case was leiomyoma, and the other was leiomyosarcoma. Among the remaining cases without change in size, 15 underwent surgical resection (n = 10) or endoscopic resection (n = 5), and all cases were confirmed as leiomyoma. CONCLUSIONS: Most gastric leiomyomas are benign SETs, and an increase in size is not frequent, even in large-sized cases. Close monitoring with routine follow-up without resection may be sufficient in cases of histologically proven gastric leiomyoma. However, in cases of ulceration or size increase, resection may be beneficial.

Clinical outcomes of argon plasma coagulation for the treatment of gastric low-grade dysplasia.

BACKGROUND AND AIMS: Argon plasma coagulation (APC) could be considered a treatment modality for small gastric low-grade dysplasia (LGD) instead of endoscopic resection. Our study investigated the clinical outcomes of APC for treating gastric LGD and associated variables with local recurrence. METHODS: This study included 911 patients who underwent APC for gastric neoplasms at the tertiary hospital from July 2007 to March 2022 with a minimal follow-up of 12 months. Of these patients, 112 without any information about Helicobacter pylori infection status, 164 who underwent APC for salvage therapy, 5 with high-grade dysplasia, and 12 with cancer were excluded. Through a retrospective review of medical data, the clinical outcomes and variables associated with the local recurrence were analyzed. RESULTS: A total of 618 patients with LGD (median age, 64 years) were followed up for a median of 30 months, and local recurrence has happened in 21 (3.4%) patients. Multivariate analysis showed that lesion size (hazard ratio, 1.06; 95% confidential interval, 1.01-1.12) was associated with the local recurrence. Among 557 lesions smaller than 10 mm, local recurrence was found in 14 (2.6%) cases, and local recurrence was found in 7 (9.5%) cases of 109 tumors larger than 10 mm (P < .004). CONCLUSIONS: In gastric LGD smaller than 10 mm without scars, APC is a good treatment modality in place of endoscopic resection. However, when a lesion is larger, APC should be selected carefully with close monitoring.

Dysphagia associated with esophageal wall thickening in patients with nonspecific high-resolution manometry findings: Understanding motility beyond the Chicago classification version 4.0.

BACKGROUND: Previous studies have demonstrated that 50% of patients with normal high-resolution manometry (HRM) findings or ineffective esophageal motility (IEM) may have abnormal functional luminal imaging probe (FLIP) results. However, the specific HRM findings associated with abnormal FLIP results are unknown. Herein, we investigated the relationship between nonspecific manometry findings and abnormal FLIP results. METHODS: We retrospectively analyzed 684 patients who underwent HRM at a tertiary care center in Seoul, Korea, based on the Chicago Classification version 4.0 protocol. KEY RESULTS: Among the 684 patients, 398 had normal HRM findings or IEM. Of these 398 patients, eight showed esophageal wall thickening on endoscopic ultrasonography or computed tomography; however, no abnormalities were seen during esophagogastroduodenoscopy. Among these eight patients, seven showed repetitive simultaneous contractions (RSCs) in at least one of the two positions: 61% (±29%) in 10 swallows in the supine position and 51% (±30%) in five swallows in the upright position. Four patients who underwent FLIP had a significantly decreased esophagogastric junction distensibility index (1.0 ± 0.5 m m 2 mmHg - 1 at 60 mL). Two of these patients underwent per-oral endoscopic myotomy (POEM) due to a lack of response to medication. Esophageal muscle biopsy revealed hypertrophic muscle with marginal eosinophil infiltration. CONCLUSIONS & INFERENCES: A subset of patients (2%) with normal HRM findings or IEM and RSCs experienced dysphagia associated with poor distensibility of the thickened esophageal wall. FLIP assessment or combined HRM and impedance protocols may help better define these patients who may respond well to POEM.

Differential Diagnosis of Thickened Gastric Wall between Hypertrophic Gastritis and Borrmann Type 4 Advanced Gastric Cancer.

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.

Usefulness of a new polyvinyl alcohol hydrogel (PVA-H)-based simulator for endoscopic submucosal dissection training: a pilot study.

BACKGROUND/AIMS: We developed a new endoscopic submucosal dissection (ESD) simulator and evaluated its efficacy and realism for use training endoscopists. METHODS: An ESD simulator was constructed using polyvinyl alcohol hydrogel sheets and compared to a previous ESD simulator. Between March 1, 2020, and December 30, 2021, eight expert endoscopists from three different centers analyzed the procedure-related factors of the simulator. Five trainees performed gastric ESD exercises under the guidance of these experts. RESULTS: Although the two ESD simulators provided overall favorable outcomes in terms of ESD-related factors, the new simulator had several benefits, including better marking of the target lesion's limits (p<0.001) and overall handling (p<0.001). Trainees tested the usefulness of the new ESD simulator. The complete resection rate improved after 3 ESD training sessions (9 procedures), and the perforation rate decreased after 4 sessions (12 procedures). CONCLUSION: We have developed a new ESD simulator that can help beginners achieve a high level of technical experience before performing real-time ESD procedures in patients.

Comparison of Diagnosis of Esophageal Motility Disorders by Chicago Classification Versions 3.0 and 4.0.

Background/Aims: We aim to investigate the diagnostic accuracy and differences between Chicago classification version 3.0 (CC v3.0) and 4.0 (CC v4.0). Methods: Patients who underwent high-resolution esophageal manometry (HRM) for suspected esophageal motility disorders were prospectively recruited between May 2020 and February 2021. The protocol of HRM studies included additional positional change and provocative testing designed by CC v4.0. Results: Two hundred forty-four patients were included. The median age was 59 (interquartile range, 45-66) years, and 46.7% were males. Of these, 53.3% (n = 130) and 61.9% (n = 151) were categorized as normalcy by CC v3.0 and CC v4.0, respectively. The 15 patients diagnosed of esophagogastric junction outflow obstruction (EGJOO) by CC v3.0 was changed to normalcy by position (n = 2) and symptom (n = 13) by CC v4.0. In seven patients, the ineffective esophageal motility (IEM) diagnosis by CC v3.0 was changed to normalcy by CC v4.0. The diagnostic rate of achalasia increased from 11.1% (n = 27) to 13.9% (n = 34) by CC v4.0. Of patients diagnosed IEM by CC v3.0, 4 was changed to achalasia based on the functional lumen imaging probe (FLIP) results by CC v4.0. Three patients (2 with absent contractility and 1 with IEM in CC v3.0) were newly diagnosed with achalasia using a provocative test and barium esophagography by CC v4.0. Conclusions: CC v4.0 is more rigorous than CC v3.0 for the diagnosis of EGJOO and IEM and diagnoses achalasia more accurately by using provocative tests and FLIP. Further studies on the treatment outcomes following diagnosis with CC v4.0 are needed.

Risk factors associated with recurrence of gastric hyperplastic polyps: a single-center, long-term, retrospective cohort study.

BACKGROUND: The likelihood of recurrence of gastric hyperplastic polyps (GHPs) following endoscopic resection and the need for long-term follow-up remain unknown. We, therefore, aimed to investigate the factors associated with the recurrence and cumulative incidence of GHPs over a 10-year period. METHODS: Between May 1995 and December 2020, 1,018 GHPs > 1 cm were endoscopically resected from 869 patients. Medical records of these patients were retrospectively reviewed and their clinical features and outcomes were assessed. Groups of GHPs with recurrence and those without recurrence group were compared, and univariate and multivariable analyses were performed to identify the potential risk factors for GHP recurrence. RESULTS: A total of 104 (12.0%) patients who underwent endoscopic removal of GHPs experienced recurrence. Compared to patients without recurrent GHPs, those with recurrent GHPs showed considerably larger median polyp size (28 mm vs. 14 mm, P < 0.001), a higher proportion of multiple polyps (41.3% vs. 29.3%, P = 0.020), polyps with lobulation (63.5% vs. 40.3%, P = 0.001), and exudate (63.5% vs. 46.8%, P = 0.001). Compared to the local recurrence (n = 52) group, the metachronous recurrence (n = 52) group had larger median polyp size (20 mm vs. 16 mm, P = 0.006) as well as higher rates of polyp lobulation (86.5% vs. 40.4%, P < 0.001) and exudate (82.7% vs. 44.4%, P = 0.001). After primary GHP excision, the cumulative incidence of recurrence was 7.2%, 12.7%, and 19.6% at 2 years, 5 years, and 10 years, respectively. CONCLUSION: The incidence of GHP recurrence following endoscopic excision increased as the follow-up period increased, especially in patients whose GHPs were large-sized, multiple, or characterized by surface exudates/lobulations.

Incidence, Morbidity, and Mortality of Achalasia: A Nationwide, Population-Based Cohort Study in South Korea.

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<0.001), aspiration pneumonia (aHR, 3.92; 95% CI, 2.38 to 6.48; p<0.001), and mortality (aHR, 1.68; 95% CI, 1.44 to 1.94; p<0.001). Esophageal cancer carried the highest mortality risk (aHR, 8.82; 95% CI, 2.35 to 33.16; p=0.001), while pneumonia had the highest non-cancer mortality risk (aHR, 2.28; 95% CI, 1.31 to 3.96; p=0.004). Conclusions: In this nationwide study, achalasia was associated with increased risk of mortality. Esophageal cancer and pneumonia were the most common comorbidities and the major causes of death in patients with achalasia.

Comparison of endoscopic submucosal dissection and surgery for early gastric cancer that is not indicated for endoscopic resection in elderly patients.

BACKGROUND: Endoscopic submucosal dissection (ESD) is sometimes performed for early gastric cancer (EGC) which is not indicated for endoscopic resection (ER) in elderly patients considering old age and comorbidities. We aimed to compare outcomes between ESD and surgery in elderly patients with EGC that is not indicated for ER. METHODS: Elderly patients aged ≥ 75 years who underwent either ESD or surgery for EGC which was not indicated for ER between 2005 and 2015 were retrospectively investigated. RESULTS: Among a total of 294 patients, 59 (20.1%) and 235 (79.9%) patients underwent ESD and surgery as the initial treatment, respectively. The ESD group had smaller size of tumors (25 vs. 30 mm, p = .001) and higher rate of differentiated-type cancer than the surgery group had (88.1% vs. 60.9%, p = 0.001). With a median observation period of 91.8 months (range 11.6-198.1 months), 141 (48.0%) patients died: 25 (42.4%) and 116 (49.4%) patients in the ESD group and the surgery group, respectively. Overall survival and disease-free survival between the two groups had no significant differences (p = 0.982. p = 0.155, respectively). CONCLUSIONS: ESD may be an alternative option for EGC which is not indicated for ER in elderly patients aged ≥ 75 years, considering old age and comorbidity.

Clinical outcomes of Dieulafoy's lesion compared with peptic ulcer in upper gastrointestinal bleeding.

BACKGROUND AND AIM: Although Dieulafoy's lesion (DL) is an important cause of nonvariceal upper gastrointestinal (GI) bleeding, few studies have investigated the clinico-epidemiological outcomes due to its rarity. Here, we investigated clinical features of upper GI bleeding caused by peptic ulcer (PU) or DL and compared endoscopic treatment outcomes. METHODS: Patients with upper GI bleeding resulting from PU or DL who visited emergency room between January 2013 and December 2017 were eligible. Clinical features and treatment outcomes were retrospectively investigated. RESULTS: Overall, 728 patients with upper GI bleeding due to PU (n = 669) and DL (n = 59) were enrolled. The median age was 64 years (interquartile range [IQR], 56-75 years), and 74.3% were male. Endoscopic intervention was performed in 53.7% (n = 359) and 98.3% (n = 58) of the PU and DL groups, respectively (P < 0.0001). Patients were matched by sex, age, body mass index, comorbidity, and past medical history, and 190 PU and 52 DL were finally selected. The rebleeding rates within 7 (7.37% vs 17.31%, P = 0.037) and 30 (7.37% vs 26.92%, P < 0.001) days after initial endoscopy were significantly lower in the PU than in the DL group after propensity score matching. During the median follow-up period of 52 months (IQR, 34-70 months), there was no difference in overall survival rate (67.9% vs 82.7%, P = 0.518). CONCLUSIONS: Although DL is a rare cause of upper GI bleeding, it requires endoscopic hemostasis more frequently and has a higher rate of rebleeding than PU even after therapeutic endoscopy. Endoscopists should pay attention and perform active endoscopic hemostasis for DL bleeding.

Clinical outcomes of marginal ulcer bleeding compared with those of peptic ulcer bleeding.

BACKGROUND: Marginal ulcer bleeding (MUB) is a complication that can occur following several types of surgery. However, few studies exist on it. Therefore, this study aimed to compare the clinical outcomes of MUB with those of peptic ulcer bleeding (PUB). METHODS: Between January 2013 and December 2017, 5,076 patients underwent emergent esophagogastroduodenoscopy for suspected upper gastrointestinal bleeding. We retrospectively reviewed and analyzed the medical records of MUB and PUB patients and developed a propensity score matching (PSM) method to adjust for between-group differences in baseline characteristics with 1:2 ratios. Sex, age, body mass index (BMI), underlying diseases, and drugs were included as matching factors. RESULTS: A total of 64 and 678 patients were diagnosed with MUB and PUB, respectively, on emergent esophagogastroduodenoscopy, and 62 and 124 patients with MUB and PUB, respectively, were selected after PSM. Rebleeding was significantly higher in patients with MUB than in those with PUB (57.8% vs 9.1%, p < 0.001). Mortality caused by bleeding was higher in patients with MUB than in those with PUB (4.7% vs. 0.4%, p < 0.001). Multivariate analysis revealed that proton pump inhibitor (PPI) administration (odds ratio [OR], 0.14; 95% confidence interval [CI], 0.03-0.56; p = 0.011) after first bleeding was inversely correlated with MUB rebleeding. Large ulcer size (> 1 cm) (OR, 6.69; 95% CI, 1.95-27.94; p = 0.005) and surgery covering pancreas (OR, 3.97; 95% CI, 1.19-15.04) were independent risk factors for MUB rebleeding. CONCLUSIONS: MUB showed a severe clinical course than PUB. Therefore, MUB should be managed more cautiously, especially for large ulcers and pancreatic surgery. Prophylactic PPI administration may be helpful in reducing rebleeding in MUB.

Simulator-based training method in gastrointestinal endoscopy training and currently available simulators.

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.

Gastric Neuroendocrine Tumors According to the 2019 World Health Organization Grading System: A Single-Center, Retrospective Study.

Background/Aims: Although gastric neuroendocrine tumors (NETs) are uncommon neoplasms, their prevalence is increasing. The clinical importance of the World Health Organization (WHO) classification of gastric NETs, compared with NETs in other organs, has been underestimated. This study aimed to systematically evaluate the clinical and pathologic characteristics of gastric NETs based on the 2019 WHO classification and to assess the survival outcomes of patients from a single-center with a long-term follow-up. Methods: The medical records of 427 patients with gastric NETs who underwent endoscopic or surgical resection between January 2000 and March 2020 were retrospectively reviewed. All specimens were reclassified according to the 2019 WHO classification. The clinicopathologic characteristics, treatment, and oncologic outcomes of 139 gastric NETs were analyzed. Results: The patients' median age was 53.0 years (interquartile range [IQR], 46.0 to 63.0 years). The median follow-up period was 36.0 months (IQR, 15.0 to 63.0 months). Of the patients, 92, 44, and 3 had grades 1, 2, and 3 NETs, respectively. The mean tumor size significantly increased as the tumor grade increased (p=0.025). Patients with grades 2 and 3 gastric NETs more frequently had lymphovascular invasion (29.8% vs 10.9%, p=0.005) and deeper tissue invasion (8.5% vs 0%, p=0.012) than those with grade 1 tumors. The overall disease-specific survival rate was 100%. Two patients with grades 2-3 gastric NETs experienced extragastric recurrence. Conclusions: Although gastric NETs have an excellent prognosis, grade 2 or grade 3 gastric NETs are associated with a larger size, deeper invasion, and extragastric recurrence, which require active treatment.

Conventional endoscopic mucosal resection versus modified endoscopic mucosal resection for duodenal neuroendocrine tumor.

BACKGROUND AND AIMS: As the incidence of duodenal neuroendocrine tumors (DNET) is steadily increasing, the role of endoscopic treatment for appropriate lesions is becoming more significant. We aimed to compare the outcomes according to lesion size and endoscopic mucosal resection (EMR) techniques for DNET treatment. PATIENTS AND METHODS: Patients who underwent endoscopic treatment for DNET between June 2000 and December 2019 were included. The clinicopathologic features and treatment outcomes were investigated by reviewing medical records. RESULTS: Overall, 104 cases underwent endoscopic resection for nonampullary DNET, including conventional EMR (n = 57), cap-assisted EMR (EMR-C, n = 19), and precut EMR (EMR-P, n = 28). The en bloc resection rates (100% vs. 94.7% vs. 96.4%) and histologic complete resection rates (45.6% vs. 52.6% vs. 57.1%) were not significantly different between the EMR, EMR-C, and EMR-P groups. The histologic complete resection rates were significantly higher in lesions < 10 mm than in lesions ≥ 10 mm (69.8% vs. 38.9%, P = 0.013). In lesions < 10 mm, perforation occurred more frequently in the modified EMR group than in the conventional EMR group (13.2% vs. 0.0%, P = 0.007). During the median follow-up period of 88.0 months, the recurrence-free survival (92.2% vs. 94.4% vs. 92.1%) and overall survival (98.0% vs. 88.1% vs. 100.0%) rates did not show significant differences between the EMR, EMR-C, and EMR-P groups. CONCLUSION: Conventional EMR and modified EMR are feasible and effective for the treatment of nonampullary DNET sized < 10 mm and limited to mucosal and submucosal layer. Additionally, endoscopists should be aware of the high risk of perforation in modified EMR.

Clinical Significance of Epstein-Barr Virus and Helicobacter pylori Infection in Gastric Carcinoma.

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<0.001). Multivariate analysis revealed that EBV infection alone (hazard ratio [HR], 0.362; 95% CI, 0.131 to 0.996; p=0.049) and lower third location (HR, 0.624; 95% CI, 0.413 to 0.943; p=0.025) were inversely correlated with overall survival. During median follow-up period of 72 months, overall survival rate was not significantly different between the EBV and HP coinfection group and others (97.6% vs 86.8%; log-rank p=0.144). In non-GCLS patients (n=920), overall survival rate was not significantly different between the EBV infection group and others (96.9% vs 86.4%; log-rank p=0.126). Conclusions: EBV and HP coinfection is not an independent prognostic factor for gastric cancer. EBV infection status, regardless of HP infection, affects the clinicopathologic features of all types of gastric cancer. However, it does not lead to a significant difference in overall survival of non-GCLS patients.

Real-Time Polymerase Chain Reaction for the Detection of Helicobacter pylori and Clarithromycin Resistance.

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.