Clinicopathologic Features and Outcomes of Endoscopic Submucosal Dissection for Foveolar-Type Adenocarcinoma of the Stomach.

PURPOSE: Foveolar-type adenocarcinoma of the stomach is a rare variant of gastric cancer. The clinicopathological features and outcomes of endoscopic submucosal dissection (ESD) for gastric foveolar-type adenocarcinoma remain unclear. MATERIALS AND METHODS: This study included 1,161 patients who underwent ESD for single early gastric cancers (EGCs) (78 foveolar-type adenocarcinomas and 1,083 well-differentiated [WD] adenocarcinomas). The clinicopathological features and short- and long-term outcomes of ESD for gastric foveolar-type adenocarcinomas were reviewed and compared with those for WD EGCs. RESULTS: Gastric foveolar-type adenocarcinomas were larger and more likely to exhibit an elevated macroscopic appearance than WD EGCs. Foveolar-type adenocarcinomas exhibited higher rates of lymphatic invasion, histological heterogeneity, and lateral margin involvement than WD EGCs. The en bloc R0 and curative resection rates of foveolar-type adenocarcinoma were 85.9% and 76.9%, respectively. Both foveolar-type adenocarcinoma rates were significantly lower than those of WD EGCs (95.8% and 91.3%, respectively). Lateral margin involvement accounted for 55.6% of the non-curative resection cases of foveolar-type adenocarcinoma. Among patients who underwent curative ESD for foveolar-type adenocarcinoma, no recurrence occurred during the median 62.3 months of follow-up. No lymph node metastases were detected in patients with foveolar-type adenocarcinoma who underwent additional surgery following ESD. The overall and disease-specific survival rates of patients with foveolar-type adenocarcinoma were comparable to those of patients with WD EGC. CONCLUSIONS: Gastric foveolar-type adenocarcinomas have distinct clinicopathological features among WD EGCs. Given favorable long-term outcomes after curative resection, ESD can be indicated for early gastric foveolar-type adenocarcinomas.

Clinicopathological Characteristics and Lymph Node Metastasis Rates in Early Gastric Lymphoepithelioma-Like Carcinoma: Implications for Endoscopic Resection.

Background/Aims: Lymphoepithelioma-like carcinoma (LELC) is a rare subtype of gastric cancer. We aimed to identify the clinicopathological features and rate of lymph node metastasis (LNM) to investigate the feasibility of endoscopic submucosal dissection for early gastric LELC confined to the mucosa or submucosa. Methods: We compared the clinicopathological characteristics of 116 early gastric LELC patients and 5,753 early gastric well- or moderately differentiated (WD or MD) tubular adenocarcinoma patients treated by gastrectomy. Results: Compared to WD or MD early gastric cancer (EGC) patients, early LELC patients were younger and had a higher prevalence of proximally located tumors. Despite more frequent deep submucosal invasion (86.2% vs 29.8%), lymphatic invasion was less frequent (6.0% vs 16.2%) in early LELC patients than in WD or MD EGC patients. Among tumors with deep submucosal invasion, the tumor size was smaller, lymphatic invasion was less frequent (6.0% vs 40.2%) and the rate of LNM was lower (10.0% vs 19.4%) in patients with LELC than in those with WD or MD EGC. The overall rate of LNM in early LELC patients was 8.6% (10/116). The risk of LNM in patients with mucosal, shallow submucosal invasive, or deep submucosal invasive LELC was 0% (0/6), 0% (0/10), and 10% (10/100), respectively. Conclusions: Early LELC is a distinct subtype of EGC with more frequent deep submucosal invasion but less lymphatic invasion and LNM than WD or MD EGCs. Endoscopic submucosal dissection may be considered curative for patients with early LELC confined to the mucosa or shallow submucosa, given its negligible rate of LNM.

Delayed Perforation Occurring after Gastric Endoscopic Submucosal Dissection: Clinical Features and Management Strategy.

Background/Aims: Delayed perforation is a rare but serious adverse event of gastric endoscopic submucosal dissection (ESD). The aim of this study was to clarify the clinical features and appropriate management strategy of patients with delayed perforation. Methods: Among 11,531 patients who underwent gastric ESD, the clinical features and outcomes of patients who experienced delayed perforation were retrospectively reviewed and compared with those of the control group. Results: Delayed perforation occurred in 15 of 11,531 patients (0.13%). The patients with delayed perforation were significantly older than those without delayed perforation (p=0.027). The median time to diagnosis of delayed perforation was 28.8 hours (range, 14 to 71 hours). All 15 patients with delayed perforation complained of severe abdominal pain after gastric ESD and underwent subsequent chest X-rays (CXRs) for evaluation. In subsequent CXR, free air was found in 12 patients (80%). For three (20%) patients without free air in CXR, delayed perforation was finally diagnosed by computed tomography. Leukocytosis was significantly less frequent in the patients without free air in CXR (p=0.022). A perforation hole smaller than 1 cm in size was more frequently observed in the six patients who underwent successful non-surgical treatments than in the nine patients who underwent surgery (p<0.001). There was no mortality related to delayed perforation. Conclusions: One-fifth of the patients with delayed perforation did not show free air in CXR and exhibited less leukocytosis than those with free air. Non-surgical treatments including endoscopic closure might be considered as an initial treatment modality for delayed perforation smaller than 1 cm.

Outcomes of Primary Esophagectomy and Esophagectomy after Endoscopic Submucosal Dissection for Superficial Esophageal Squamous Cell Carcinoma: A Propensity-Score-Matched Analysis.

Even though the conventional treatment for T1 esophageal cancer is surgery, ESD is becoming the primary treatment. Currently, it is unknown whether secondary esophagectomy after endoscopic submucosal dissection (ESD) is comparable to primary esophagectomy when considering outcomes in patients with T1 esophageal cancer. We compared short- and long-term clinical outcomes between the two groups. Primary surgery (esophagectomy) was performed in 191 patients between 2003 and 2014, and 62 patients underwent secondary surgery (esophagectomy) after ESD for T1 esophageal cancer between 2007 and 2019. Propensity matching was performed for age, sex, Charlson Comorbidity Index (CCI), location, pathology, degree of differentiation, tumor size, and invasion depth. Lymph node metastasis (LNM), overall survival (OS), disease-specific survival (DSS), recurrence-free survival (RFS), and post-operative complications were compared between groups. Sixty-eight patients were included after propensity score matching; LNM, OS, DSS, and RFS were comparable between the two groups. Comparing primary and secondary surgery, the respective LNM rates were 23.5% and 26.5%, 6-year OS 78.0% and 89.7%, p = 0.15; DSS were 80.4% and 96.8%, p = 0.057; and RFS were 80.8% and 89.7%, p = 0.069. Comparing the adverse events between the two groups, there was no significant difference in the overall adverse events. However, more early complications were observed in the primary surgery group than in the secondary surgery group (50% vs. 20.6%, p = 0.021). Secondary surgery did not increase the risk of LNM. The long-term outcomes were comparable. Therefore, attempts to perform upfront ESD for superficial esophageal squamous cell cancers are justified.

Antithrombotic Therapy Increases the Risk of Bleeding after Endoscopic Submucosal Dissection for Early Gastric Cancer: A Propensity Score-Matched Analysis.

Whether antithrombotic agent (ATA) usage increases the risk of gastric post-endoscopic submucosal dissection (ESD) bleeding remains controversial. The aim of this study was to elucidate the effects of usage, type, and cessation timing of ATA on post-ESD bleeding. A total of 4775 early gastric cancer patients undergoing ESD were analyzed; 1:3 propensity score matching between ATA and non-ATA groups resulted in 318 and 767 matched patients in each group, respectively. Outcomes were compared between the two groups using a generalized estimating equation method. After matching, post-ESD bleeding rates in ATA users and non-users were 9.1% and 4.2%, respectively (p = 0.001). In multivariable analysis, ATA usage was independently associated with an increased risk of post-ESD bleeding (adjusted odds ratio: 2.28, 95% confidence interval: 1.34-3.86). Both the continued or insufficient cessation groups and the sufficient cessation group had an increased incidence of post-ESD bleeding compared to their matched controls (12.5% versus 5.2%, p = 0.048; 8.1% versus 3.9%, p = 0.014). Post-ESD bleeding rates in antiplatelet agent users were significantly higher than those of their matched controls (8.3% versus 4.2%, p = 0.010). ATA usage increased the risk of post-ESD bleeding even after its sufficient cessation. Careful observation after ESD is required regardless of the cessation status of ATA.

Effect of renal insufficiency on the short- and long-term outcomes of endoscopic submucosal dissection for early gastric cancer: Propensity score-matched analysis.

OBJECTIVES: It is unclear whether renal insufficiency (RI) itself is a risk factor for adverse outcomes after gastric endoscopic submucosal dissection (ESD). We aimed to evaluate the safety and efficacy of gastric ESD in patients with and without RI using propensity score-matching analysis. METHODS: In all, 4775 patients with 4775 early gastric cancer lesions undergoing ESD were analyzed. 1:1 propensity score-matching was performed between patients with and without RI using 12 variables. After matching, logistic regression and survival analyses were performed for short- and long-term outcomes of ESD, respectively. RESULTS: The matching yielded 188 pairs of patients with and without RI. In both univariable and multivariable analyses, the presence of RI was not significantly associated with postprocedural bleeding (unadjusted odds ratio 1.81, 95% confidence interval 0.74-4.42; adjusted odds ratio 1.86, 95% confidence interval 0.74-4.65, respectively). When RI patients were subclassified into patients with estimated glomerular filtration rate (eGFR) 30-59 mL/min/1.73 m2 and eGFR <30 mL/min/1.73 m2 , no significant differences in bleeding rates were found compared to their matched controls in both groups. Perforation, en bloc resection, en bloc and R0 resection, and curative resection rates of RI patients were 2.1%, 98.4%, 91.0%, and 78.2%, respectively, which were comparable to those of non-RI patients. During a median follow-up of 119 months, there was no difference in gastric cancer-specific survival between patients with and without RI (P = 0.143). CONCLUSION: The outcomes of ESD were comparable in patients with and without RI. Decreased renal function itself may not be a reason to keep patients with RI from receiving gastric ESD.

A Median Arcuate Ligament Syndrome Could Be Re-termed as a Nutcracker Celiac Ganglion Abdominal Pain Syndrome.

Background/Aims: Median arcuate ligament syndrome (MALS) is known as chronic recurrent abdominal pain related to compression of the celiac artery by the median arcuate ligament. We aim to seek the specific mechanism of the pain by evaluating symptoms and radiological characteristics on abdominal CT scans. Methods: We analyzed 35 patients who visited the emergency room for recurrent abdominal pain after cholecystectomy. We classified the characteristics of patients as 4 clinical components and 2 radiological components. We defined the sum of weighted clinical scores and weighted radiological scores as nutcracker ganglion abdominal pain syndrome (NCGAPS) scores. We categorized the patients into 3 groups classified by the degree of NCGAPS scores. The 3 patients with top-3 NCGAPS scores were recommended for CT angiography. Results: When the suspicion was graded by NCGAPS scores, post stenotic dilatation was significantly different among all groups (P < 0.001). The clinical components of pain varied positional or respirational change and continuous pain were significantly different among all the groups (P < 0.01). NCGAPS scores can remarkably differentiate highly suspicious patients in comparison to simply combined scores. Only 1 patient in the highly suspicious group by NCGAPS scores took the CT angiography and was confirmed with NCGAPS. Conclusions: We suggest renaming MALS as NCGAPS, nutcracker celiac ganglion abdominal pain syndrome, to better explain the mechanism of the recurrent abdominal pain. Further studies on the diagnostic cutoff of clinical and radiological scores of NCGAPS are needed not to miss the diagnosis of NCGAPS.

Outcomes of Endoscopic Resection for Early Gastric Cancer in Very Elderly Patients: A Nationwide Population-Based Study.

Background/Aims: Few studies have investigated the long-term outcomes of endoscopic resection for early gastric cancer (EGC) in very elderly patients. The aim of this study was to determine the appropriate treatment strategy and identify the risk factors for mortality in these patients. Methods: Patients with EGC who underwent endoscopic resection from 2006 to 2017 were identified using National Health Insurance Data and divided into three age groups: very elderly (≥85 years), elderly (65 to 84 years), and non-elderly (≤64 years). Their long- and short-term outcomes were compared in the three age groups, and the survival in the groups was compared with that in the control group, matched by age and sex. We also evaluated the risk factors for long- and short-term outcomes. Results: A total of 8,426 patients were included in our study: 118 very elderly, 4,583 elderly, and 3,725 non-elderly. The overall survival and cancer-specific survival rates were significantly lower in the very elderly group than in the elderly and the non-elderly groups. Congestive heart failure was negatively associated with cancer-specific survival. A significantly decreased risk for mortality was observed in all groups (p<0.001). The very elderly group had significantly higher readmission and mortality rates within 3 months of endoscopic resection than the non-elderly and elderly groups. Furthermore, the cerebrovascular disease was associated with mortality within 3 months after endoscopic resection. Conclusions: Endoscopic resection for EGC can be helpful for very elderly patients, and it may play a role in achieving overall survival comparable to that of the control group.

Randomised clinical trial: comparison of tegoprazan and lansoprazole as maintenance therapy for healed mild erosive oesophagitis.

BACKGROUND: Tegoprazan is a novel potassium-competitive acid blocker used to treat acid-related disorders. AIM: To compare tegoprazan 25 mg with lansoprazole 15 mg as maintenance therapy in healed erosive oesophagitis (EE) METHODS: In this phase 3, double-blind, multi-centre study, patients with endoscopically confirmed healed EE were randomised 1:1 to receive tegoprazan 25 mg or lansoprazole 15 mg once daily for up to 24 weeks. The primary efficacy endpoint was the endoscopic remission rate after 24 weeks. The secondary efficacy endpoint was the endoscopic remission rate after 12 weeks. Safety endpoints included adverse events, clinical laboratory results and serum gastrin and pepsinogen I/II levels. RESULTS: We randomised patients to tegoprazan 25 mg (n = 174) or lansoprazole 15 mg (n = 177). Most had mild EE (Los Angeles (LA) grade A: 57.3%, LA grade B: 37.3%). The endoscopic remission rate after 24 weeks was 90.6% with tegoprazan and 89.5% with lansoprazole. Tegoprazan was not inferior to lansoprazole for maintaining endoscopic remission at 24 weeks and 12 weeks. In subgroup analysis, tegoprazan 25 mg showed no significant difference in maintenance rate according to LA grade (p = 0.47). The maintenance effect of tegoprazan was consistent in CYP2C19 extensive metabolisers (p = 0.76). Increases in serum gastrin were not higher in tegoprazan-treated than lansoprazole-treated patients. CONCLUSIONS: Tegoprazan 25 mg was non-inferior to lansoprazole 15 mg in maintenance of healing of mild EE. In this study, tegoprazan had a similar safety profile to lansoprazole.

Interval Advanced Gastric Cancer After Negative Endoscopy.

BACKGROUND & AIMS: Esophagogastroduodenoscopy (EGD) is effective in reducing gastric cancer mortality through detection of early-stage cancer in areas with a high prevalence of gastric cancer. Although the risk of post-endoscopy advanced gastric cancer (AGC) is low, interval AGC remains a concern. We investigated the characteristics and predictors of interval AGC after negative EGD. METHODS: We included 1257 patients with gastric cancer within 6 to 36 months of a "cancer-negative" index EGD between 2005 and 2021 at a tertiary university hospital in South Korea. Observation time on the index EGD was used as a quality indicator. We compared the clinical and endoscopic characteristics and quality indicators between interval AGC and screen-detected early gastric cancer (EGC). RESULTS: Within 6 to 36 months of negative EGD, 102 AGCs (8.1%) and 1155 EGCs (91.9%) were identified. The percentage of patients with shorter observation time (<3 minutes) in the index EGD was higher in the interval AGC group than in the detected EGC group (P = .002). A multivariable analysis comparing screen-detected EGD and interval AGC was adjusted for age, sex, family history of gastric cancer, H. pylori status, endoscopic findings, and endoscopy-related factors including gastric observation time and interval time. A shorter observation time (<3 minutes) (odds ratio, 2.27; 95% confidence interval, 1.20-4.30), and interval time >2 years (odds ratio, 1.84; 95% confidence interval, 1.04-3.24) were associated with an increased risk of interval AGC. CONCLUSION: A shorter observation time during index EGD is an important predictor of interval AGC. Further, withdrawal time longer than 3 minutes may be a quality indicator for screening EGD.

[Ectopic Pancreas with Walled-off Necrosis Mimicking Malignant Submucosal Gastric Tumor].

An ectopic pancreas rarely transforms into a malignancy, and the symptoms vary from patient to patient. The most commonly observed site of an ectopic pancreas is the antrum of the stomach. A 59-year-old male patient with severe abdominal pain underwent CT. A 9.6 cm-sized well-defined exophytic huge mass with heterogenic density was located between the stomach distal antrum and duodenum. A malignant submucosal tumor was suspected because of the exophytic dirty huge mass. Initially, surgery was considered to confirm the histological evaluation. After 2 months, the abdominal pain disappeared, and the follow-up MRI scan showed a decrease in size, which contained a necrotic component inside. It was confirmed that the parenchymal tissue was the pancreas. The pathology through EUS-guided fine needle aspiration (EUS-FNA) was normal pancreatic acinar cells, smooth muscle fragments, squamous cyst, and some neutrophils (abscess). Walled-off necrosis occurs as a complication of acute pancreatitis with parenchymal tissues and surrounding tissues, but complications of ectopic pancreatitis occurred in this case. Abdominal pain due to ectopic pancreas leading to the formation of a giant abscess has been reported as a very rare case. Diagnosis through biopsy is most important when a malignant submucosal tumor is suspected. In addition, it is important to determine the clinical features, examination findings, such as EUS, CT, and MRI, and the changes according to the follow-up period. This paper reports a case of ectopic pancreas, resulting in necrotic tissue and walled-off necrosis, abdominal pain, and spontaneous improvement.

Utility of a deep learning model and a clinical model for predicting bleeding after endoscopic submucosal dissection in patients with early gastric cancer.

BACKGROUND: Bleeding is one of the major complications after endoscopic submucosal dissection (ESD) in early gastric cancer (EGC) patients. There are limited studies on estimating the bleeding risk after ESD using an artificial intelligence system. AIM: To derivate and verify the performance of the deep learning model and the clinical model for predicting bleeding risk after ESD in EGC patients. METHODS: Patients with EGC who underwent ESD between January 2010 and June 2020 at the Samsung Medical Center were enrolled, and post-ESD bleeding (PEB) was investigated retrospectively. We split the entire cohort into a development set (80%) and a validation set (20%). The deep learning and clinical model were built on the development set and tested in the validation set. The performance of the deep learning model and the clinical model were compared using the area under the curve and the stratification of bleeding risk after ESD. RESULTS: A total of 5629 patients were included, and PEB occurred in 325 patients. The area under the curve for predicting PEB was 0.71 (95% confidence interval: 0.63-0.78) in the deep learning model and 0.70 (95% confidence interval: 0.62-0.77) in the clinical model, without significant difference (P = 0.730). The patients expected to the low- (< 5%), intermediate- (≥ 5%, < 9%), and high-risk (≥ 9%) categories were observed with actual bleeding rate of 2.2%, 3.9%, and 11.6%, respectively, in the deep learning model; 4.0%, 8.8%, and 18.2%, respectively, in the clinical model. CONCLUSION: A deep learning model can predict and stratify the bleeding risk after ESD in patients with EGC.

The effects of oral steroid duration on stricture prevention after extensive endoscopic submucosal dissection for superficial esophageal cancer.

Background: Esophageal stricture is a major complication of endoscopic submucosal dissection (ESD) in patients with superficial esophageal cancer (SEC). Oral steroids have been used to prevent esophageal stricture in patients with more than 75% of the esophageal circumference resected. However, there are no established guidelines regarding the optimal duration of steroid use. This retrospective observational study aimed to compare the incidence of esophageal stricture according to the period of prophylactic oral steroid use and to identify the risk factors for esophageal stricture. Methods: Eighty-one patients who were prescribed prophylactic steroid after undergoing ESD for SEC with more than 75% of esophageal circumference resected were enrolled. Patients were classified into the four-week steroid group (n=72) or eight-week steroid group (n=9) to compare the incidence of esophageal stricture. In addition, the patients were subdivided into those who developed esophageal stricture (n=24) and those who did not (n=57) to identify the risk factors for esophageal stricture. Results: Twenty patients (27.8%) in the four-week oral steroid group and four patients (44.4%) in the eight-week oral steroid group developed esophageal stricture (P=0.44). The univariable analysis identified tumor size, longitudinal length of semi-circumferential resection, and proportion of circumferential resection as risk factors of esophageal stricture. The multivariable analysis identified the proportion of circumferential resection as an independent risk factor. After adjusting for the proportion of circumferential resection, the incidence of stricture was marginally higher in the eight-week steroid group [P=0.05; odds ratio (OR): 5.69; 95% confidence interval (CI): 1.01-32.15]. Conclusions: Eight weeks of oral steroid prophylaxis does not reduce the risk of stricture after extensive ESD more than four weeks of oral steroid prophylaxis. The proportion of circumferential resection is the strongest risk factor for stricture in patients with SEC undergoing ESD.

Propulsive colonic contractions are mediated by inhibition-driven poststimulus responses that originate in interstitial cells of Cajal.

The peristaltic reflex is a fundamental behavior of the gastrointestinal (GI) tract in which mucosal stimulation activates propulsive contractions. The reflex occurs by stimulation of intrinsic primary afferent neurons with cell bodies in the myenteric plexus and projections to the lamina propria, distribution of information by interneurons, and activation of muscle motor neurons. The current concept is that excitatory cholinergic motor neurons are activated proximal to and inhibitory neurons are activated distal to the stimulus site. We found that atropine reduced, but did not block, colonic migrating motor complexes (CMMCs) in mouse, monkey, and human colons, suggesting a mechanism other than one activated by cholinergic neurons is involved in the generation/propagation of CMMCs. CMMCs were activated after a period of nerve stimulation in colons of each species, suggesting that the propulsive contractions of CMMCs may be due to the poststimulus excitation that follows inhibitory neural responses. Blocking nitrergic neurotransmission inhibited poststimulus excitation in muscle strips and blocked CMMCs in intact colons. Our data demonstrate that poststimulus excitation is due to increased Ca2+ transients in colonic interstitial cells of Cajal (ICC) following cessation of nitrergic, cyclic guanosine monophosphate (cGMP)-dependent inhibitory responses. The increase in Ca2+ transients after nitrergic responses activates a Ca2+-activated Cl− conductance, encoded by Ano1, in ICC. Antagonists of ANO1 channels inhibit poststimulus depolarizations in colonic muscles and CMMCs in intact colons. The poststimulus excitatory responses in ICC are linked to cGMP-inhibited cyclic adenosine monophosphate (cAMP) phosphodiesterase 3a and cAMP-dependent effects. These data suggest alternative mechanisms for generation and propagation of CMMCs in the colon.

Clinical characteristics and treatment outcomes of primary malignant melanoma of esophagus: a single center experience.

BACKGROUND: Primary malignant melanoma of esophagus (PMME) is an extremely rare disease with poor prognosis. We aimed to determine the clinical characteristics and treatment outcomes of patients with PMME. METHODS: We retrospectively reviewed 17 patients diagnosed with PMME in Samsung Medical Center between 2000 and 2020 with median 34 months of follow-up. Survival outcomes were analyzed with Kaplan-Meier method. RESULTS: 15 patients (88.2%) were male and the most common presenting symptom was dysphagia (9/17, 52.9%). On endoscopy, tumors were mass-forming in 15 patients (88.2%) and diffusely infiltrative in two patients (11.8%). Lesions were melanotic in 13 patients (76.5%) and amelanotic in four patients (23.5%). The most common tumor location was lower esophagus (11/17, 64.7%). The disease was metastatic at the time of diagnosis in four patients (23.5%). As for treatment, 10 patients (58.8%) underwent surgery. In all 17 patients, the median overall survival was 10 months. In surgically treated patients, all patients experienced recurrence and the median disease-free survival was 4 months. There was no statistical difference in overall survival between patients with or without surgery. Patients with diffusely infiltrative tumor morphology had better overall survival compared to those with mass-forming tumor morphology (P = 0.048). Two patients who received immunotherapy as the first-line treatment without surgery showed overall survival of 34 and 18 months, respectively. CONCLUSIONS: As radical resection for patients with PMME does not guarantee favorable treatment outcomes, novel treatment strategy is required. Further large-scale studies are warranted to determine the efficacy of immunotherapy for patients with PMME.

Machine Learning Model to Stratify the Risk of Lymph Node Metastasis for Early Gastric Cancer: A Single-Center Cohort Study.

Stratification of the risk of lymph node metastasis (LNM) in patients with non-curative resection after endoscopic resection (ER) for early gastric cancer (EGC) is crucial in determining additional treatment strategies and preventing unnecessary surgery. Hence, we developed a machine learning (ML) model and validated its performance for the stratification of LNM risk in patients with EGC. We enrolled patients who underwent primary surgery or additional surgery after ER for EGC between May 2005 and March 2021. Additionally, patients who underwent ER alone for EGC between May 2005 and March 2016 and were followed up for at least 5 years were included. The ML model was built based on a development set (70%) using logistic regression, random forest (RF), and support vector machine (SVM) analyses and assessed in a validation set (30%). In the validation set, LNM was found in 337 of 4428 patients (7.6%). Among the total patients, the area under the receiver operating characteristic (AUROC) for predicting LNM risk was 0.86 in the logistic regression, 0.85 in RF, and 0.86 in SVM analyses; in patients with initial ER, AUROC for predicting LNM risk was 0.90 in the logistic regression, 0.88 in RF, and 0.89 in SVM analyses. The ML model could stratify the LNM risk into very low (<1%), low (<3%), intermediate (<7%), and high (≥7%) risk categories, which was comparable with actual LNM rates. We demonstrate that the ML model can be used to identify LNM risk. However, this tool requires further validation in EGC patients with non-curative resection after ER for actual application.

Median arcuate ligamentum syndrome: Four case reports.

BACKGROUND: Median arcuate ligamentum syndrome (MALS) is a disease entity with unclear pathogenesis. If it is not considered in advance, the clinical diagnosis of the disease is very difficult because patients complain of digestive discomfort including pain. However, this characteristic is not specific to MALS. There have been no studies to assist in making a quick diagnosis. The aim of this case series was to recognize that MALS must be considered as a differential factor in the cause of abdominal pain. CASE SUMMARY: We described cases in which four patients complained of abdominal pain over a long period but in whom a diagnosis of MALS could not be made. If the gastroenterologist does not take into account abdominal pain in advance, the patient is considered an asymptomatic gallstone patient and has their gallbladder removed despite imaging evaluation. The patient may also be considered a psychiatric patient and may be administered psychiatric drugs over a long period. In all four cases in this report, the patients experienced abdominal pain. In three cases, the diagnosis was possible by the clinician's judgment considering both clinical symptoms and imaging techniques shortly after the onset of symptoms. However, in one case that lasted over 20 years, a clear diagnosis was not possible. Even after complaining of colicky pain and performing a cholecystectomy, the diagnosis was made only after the symptoms persisted. In all four cases, the symptoms were relieved by neuromodulators. CONCLUSION: MALS is a rare disease and it is easy to miss because it is not malignant, but patients can suffer from pain over a long period. For the accurate diagnosis of a patient complaining of abdominal pain, the diagnosis must be differentiated. In addition, as there are asymptomatic patients, patients who need treatment should be carefully selected, and improvement with medical treatment can be expected. Large-scale studies are also needed.

Long-term Outcomes of Additional Endoscopic Treatments for Patients with Positive Lateral Margins after Endoscopic Submucosal Dissection for Early Gastric Cancer.

Background/Aims: It is uncertain whether additional endoscopic treatment may be chosen over surgery in patients with positive lateral margins (pLMs) as the only non-curative factor after endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). We aimed to compare the long-term outcomes of additional endoscopic treatments in such patients with those of surgery and elucidate the clinicopathological factors that could influence the treatment selection. Methods: A total of 99 patients with 101 EGC lesions undergoing additional treatment after noncurative ESD with pLMs as the only non-curative factor were analyzed. Among them, 25 (27 lesions) underwent ESD, 29 (29 lesions) underwent argon plasma coagulation (APC), and 45 (45 lesions) underwent surgery. Clinicopathological characteristics and long-term outcomes were compared. Results: Residual tumor was found in 73.6% of cases. The presence of multiple pLMs was associated with higher risk of residual tumor (p=0.046). During a median follow-up of 58.9 months, recurrent or residual lesions after additional ESD and APC were found in 4% (1/25) and 6.8% (2/29) of patients, respectively. However, all were completely cured with surgery or repeated ESD. There were no extragastric recurrences after additional endoscopic treatment. Lymph node metastasis was identified after additional surgery in one (2.2%) patient with an EGC showing histological heterogeneity. Conclusions: Given the favorable long-term outcomes, additional ESD or APC may be an acceptable choice for patients with pLMs as the only non-curative factor after ESD for EGC. However, clincopathological characteristics such as multiple pLMs and histological heterogeneity should be considered in the treatment selection.

Clinical Outcomes and Adverse Events of Gastric Endoscopic Submucosal Dissection of the Mid to Upper Stomach under General Anesthesia and Monitored Anesthetic Care.

BACKGROUND/AIMS: Endoscopic submucosal dissection (ESD) of gastric tumors in the mid-to-upper stomach is a technically challenging procedure. This study compared the therapeutic outcomes and adverse events of ESD of tumors in the mid-to-upper stomach performed under general anesthesia (GA) or monitored anesthesia care (MAC). METHODS: Between 2012 and 2018, 674 patients underwent ESD for gastric tumors in the midbody, high body, fundus, or cardia (100 patients received GA; 574 received MAC). The outcomes of the propensity score (PS)-matched (1:1) patients receiving either GA or MAC were analyzed. RESULTS: The PS matching identified 94 patients who received GA and 94 patients who received MAC. Both groups showed high rates of en bloc resection (GA, 95.7%; MAC, 97.9%; p=0.68) and complete resection (GA, 81.9%; MAC, 84.0%; p=0.14). There were no significant differences between the rates of adverse events (GA, 16.0%; MAC, 8.5%; p=0.18) in the anesthetic groups. Logistic regression analysis indicated that the method of anesthesia did not affect the rates of complete resection or adverse events. CONCLUSION: ESD of tumors in the mid-to-upper stomach at our high-volume center had good outcomes, regardless of the method of anesthesia. Our results demonstrate no differences between the efficacies and safety of ESD performed under MAC and GA.

Clinical feasibility and oncologic safety of primary endoscopic submucosal dissection for clinical submucosal invasive early gastric cancer.

PURPOSE: This study aimed to evaluate the clinical feasibility and oncologic safety of primary endoscopic submucosal dissection for cT1bN0M0 gastric cancer by identifying patients who had undergone curative resection after endoscopic submucosal dissection and patients who had undergone primary surgery but could be treated with endoscopic submucosal dissection. METHODS: A single-center retrospective cohort study was conducted on patients with cT1bN0M0 gastric cancer (size: ≤ 30 mm) and differentiated histology from January 2007 to May 2017. Submucosal invasion was evaluated using conventional endoscopy and endoscopic ultrasonography. Patients were divided into the primary endoscopic submucosal dissection and primary surgery groups according to initial treatment. RESULTS: Curative resection rate was 65.0% (91/140) in the primary endoscopic submucosal dissection group. Of patients in the primary surgery group, 49.1% (82/167) were considered eligible for endoscopic submucosal dissection. No differences in en bloc resection rate were observed between pT1a and pT1b gastric cancers after endoscopic submucosal dissection (97.8 vs. 97.9%). However, the negative horizontal margin rate was higher in pT1a gastric cancer than pT1b gastric cancer (98.9 vs. 91.3%). There was no difference in overall survival among the curative treatment groups (log rank P = 0.310). CONCLUSION: In this study, 173 (56.4%) out of 307 patients with cT1bN0M0 gastric cancer could avoid unnecessary surgery if primary endoscopic submucosal dissection was used. Based on these findings, it is necessary to add an appropriate indication for endoscopic submucosal dissection in patients with cT1b gastric cancer. Further management could be determined based on pathologic findings after primary endoscopic submucosal dissection.