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Background/Aims: The effect of proton pump inhibitors (PPIs) on the lower gastrointestinal (GI) tract is uncertain, with potential to worsen damage. This study aimed to find the best method for protecting the entire GI tract from mucosal damage. Methods: A retrospective cohort study at Samsung Medical Center (2002-2019) included 195,817 patients prescribed GI mucosa-damaging agents. The primary goal was to assess the effectiveness of GI protective agents in preventing significant hemoglobin drops (>2 g/dL), indicating overall GI mucosal damage. Self-controlled case series and landmark analysis were used to address biases in real-world data. Results: The incidence rate ratios for rebamipide, PPI, and histamine-2 receptor antagonist (H2RA) were 0.34, 0.33, and 0.52, respectively. Rebamipide showed a significantly lower incidence rate than H2RA and was comparable to PPIs. Landmark analysis revealed significant reductions in hemoglobin drop risk with rebamipide and H2RA, but not with PPI. Conclusions: Rebamipide, like PPIs, was highly effective in preventing blood hemoglobin level decreases, as shown in real-world data. Rebamipide could be a comprehensive strategy for protecting the entire GI tract, especially when considering PPIs' potential side effects on the lower GI tract.

Objectives: The indications for endoscopic submucosal dissection (ESD) for gastric adenoma and gastric cancer have expanded, leading to an increase in the number of patients with high procedural complexity. Post-ESD perforations prolong hospital stays and increase costs. However, no studies have focused on detecting micro-perforations during ESD. This study aimed to identify signs of perforation using abdominal ultrasound during gastric ESD. Materials and methods: This pilot study analyzed 50 patients who underwent abdominal ultrasound (VScan Air™, GE Healthcare) during ESD at Samsung Medical Center (March 2023–July 2024). Perforation was assessed via ultrasound, and post-procedure X-rays were performed for three days to detect free air. Results: Among 50 patients (median age 60, 76.1% male), the median procedure time was 60 min. Lesions were most common in the antrum (30.4%) and lesser curvature (17.4%). Pathology revealed 32.6% well-differentiated and 10.9% moderately differentiated adenomas, with 15.2% showing high-grade dysplasia. Free air was detected in three patients after procedures involving the body wall of the stomach. Abdominal US showed indirect signs of perforation, including an abnormal peritoneal line, hyperechoic shadowing, and an absence of normal gas patterns, confirmed by X-ray. Conclusions: Abdominal US is a simple, useful tool for rapid detection of perforation during ESD, enabling timely intervention. Further multicenter studies are needed to confirm these findings.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This article explores the influence of dietary factors on gastric cancer (GC) incidence. While the global prevalence of Helicobacter pylori (HP) infection, a major risk factor for GC, has decreased, there is a need to focus on other modifiable risk factors, particularly nutritional factors. The study found that high sodium intake and low vitamin D levels were positively associated with GC incidence, while soluble dietary fiber intake was inversely associated with GC incidence. The study suggests that soluble fiber, found in fruits and vegetables, may have a protective effect against GC. Further research is needed to confirm these findings and explore the impact of dietary factors on GC incidence. [Extracted from the article]

Background/Aims Perforation during endoscopic submucosal dissection (ESD) is a serious complication that requires rapid diagnosis and management. Perforations detected after ESD procedures prolong the hospital stay and increase medical expenses. However, there has been no research on methods to try to detect micro-perforation during the procedure. This study aimed to identify signs of perforation using abdominal ultrasound during gastric ESD. Methods This pilot study is based on a prospective cohort registry of 88 patients diagnosed with gastric adenoma or early gastric cancer(EGC) at Samsung Medical Center between March 1, 2022, and December 1, 2023, recruited by endoscopists with less than one year of ESD experience. After excluding 39 patients who were unable to undergo abdominal ultrasound, 49 patients who consented to abdominal US (VScan AirTM, GE Healthcare, Illinois, USA) during ESD were analyzed. Perforation was predicted using US during ESD, with detailed documentation of the ultrasound findings. Post-procedure, all patients underwent X-ray imaging for three days to check for the presence of free air. Results In a 49-patient study, median age 60, 76.1% male, the median procedure time was 60 minutes. Lesions most common in the antrum (30.4%) and lesser curvature (17.4%). Pathology showed 32.6% well-differentiated, 10.9% moderately differentiated, and high-grade dysplasia (15.2%). In three patients, free air was detected following a procedure targeting the lower body anterior wall of the stomach, a technically challenging site. Abdominal ultrasound demonstrated indirect signs suggestive of gastrointestinal perforation, including an abnormal peritoneal line, hyperechoic posterior shadowing, and the absence of a normal gas pattern. These findings raised suspicion of perforation, which was subsequently confirmed by abdominal X-ray. Conclusion Abdomen US can be a simple useful tool for the rapid detection of perforation during ESD, allowing for timely intervention and improved patient outcomes. Further multicenter or prospective studies are necessary to validate these findings. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: When patients with early gastric cancer (EGC) undergo non-curative endoscopic submucosal dissection requiring gastrectomy (NC-ESD-RG), additional medical resources and expenses are required for surgery. To reduce this burden, predictive model for NC-ESDRG is required. Materials and Methods: Data from 2,997 patients undergoing ESD for 3,127 forceps biopsyproven differentiated-type EGCs (2,345 and 782 in training and validation sets, respectively) were reviewed. Using the training set, the logistic stepwise regression analysis determined the independent predictors of NC-ESD-RG (NC-ESD other than cases with lateral resection margin involvement or piecemeal resection as the only non-curative factor). Using these predictors, a risk-scoring system for predicting NC-ESD-RG was developed. Performance of the predictive model was examined internally with the validation set. Results: Rate of NC-ESD-RG was 17.3%. Independent pre-ESD predictors for NC-ESD-RG included moderately differentiated or papillary EGC, large tumor size, proximal tumor location, lesion at greater curvature, elevated or depressed morphology, and presence of ulcers. A risk-score was assigned to each predictor of NC-ESD-RG. The area under the receiver operating characteristic curve for predicting NC-ESD-RG was 0.672 in both training and validation sets. A risk-score of 5 points was the optimal cut-off value for predicting NCESD- RG, and the overall accuracy was 72.7%. As the total risk score increased, the predicted risk for NC-ESD-RG increased from 3.8% to 72.6%. Conclusions: We developed and validated a risk-scoring system for predicting NC-ESD-RG based on pre-ESD variables. Our risk-scoring system can facilitate informed consent and decision-making for preoperative treatment selection between ESD and surgery in patients with EGC. [ABSTRACT FROM AUTHOR]

Background/Aims Differentiated-type-predominant early gastric cancer with histological heterogeneity (EGC-HH) including minor undifferentiated component has more aggressive clinicopathologic behaviors and higher risk of lymph node metastasis than pure differentiated-type EGC without undifferentiated component. Long-term outcomes of endoscopic submucosal dissection (ESD) for EGC-HH remain unclear. Methods This study included 277 patients with 278 EGC-HH treated with ESD between 2007 and 2014. After ESD, EGC-HH was managed in the same way as pure differentiated- type EGC. The clinicopathologic characteristics and short- and long-term outcomes of ESD for EGC-HH were reviewed. Results Among 278 EGC-HHs, submucosal invasion, lymphatic invasion, and lateral resection margin involvement rates were 42.5%, 29.5%, and 10.1%, respectively. En bloc and R0 resection and curative resection rates were 84.5% and 49.3%, respectively. During a median 59 months of follow-up after curative ESD, six patients had metachronous recurrence (4.7%) and one patient underwent extragastric recurrence in a regional lymph node (0.8%) (Fig. 1). All recurrence cases were curatively treated with ESD or gastrectomy. The 5-year overall survival rates were 93.6% and 98.0% for patients with EGC-HH meeting the curative endoscopic resection criteria for tumors of absolute or expanded indications, respectively. Conclusions ESD showed favorable long-term outcomes and can be an acceptable treatment option for EGC-HH meeting the curative endoscopic resection criteria. After curative ESD for EGC-HH, careful follow-up with abdominal computed tomography is required. [ABSTRACT FROM AUTHOR]

Background/Aims Although metastases is the key determining factor of survival in pancreatic ductal adenocarcinoma (PDAC) patients, the genetic alteration behind the mechanism of metastases remains unclear. We aimed to identify the genetic alteration that endows metastatic potential to primary PDAC by comparing whole exome sequencing results of primary PDAC and paired liver metastases samples from living, treatment-naïve patients. Methods Whole exome sequencing analyses were performed for 11 paired sets of fine needle aspiration (FNA) samples from primary PDAC, percutaneous liver biopsy samples, and white blood cell (WBC) samples acquired form living, treatment-naïve PDAC patients with liver metastases (stage IV). Somatic mutation profiles, somatic copy number alterations profile, and tumor phylogeny were analyzed. Results Median age of study patients was 71 years old. Sex ratio was 5:6 (male:female). The median overall survival of study patients was 4.3 months. The first line chemotherapy regimens of enrolled patients were FOLFIRINOX ([3/11, 27.3%], Gemcitabine/Erlotinib [3/11, 27.3%], Gemcitabine/Abraxane [2/11, 18.2%], and Gemcitabine/Capecitabine [1/11, 9.0%]). Two patients (18.2%) could not receive chemotherapy due to the patients' wishes, old age or poor performance status. Average read depth per exon exceeded 100 times in all tumor samples and exceeded 50 times in all WBC samples. Proportion of exon areas with 10 times or higher read depth reached nearly 100%. Among 22 FNA or liver metastases samples, average purity and ploidy was 0.36 and 2.4, respectively. There were sharing mutations between primary cancers and liver metastasis, however, specific nonsharing mutations were existed. Conclusions Whole Exome sequencing of primary pancreatic cancer and liver metastasis revealed both shared genomic signature, interestingly, we could also find unique unshared mutations of liver metastasis. [ABSTRACT FROM AUTHOR]

Objectives Localized gastric Langerhans cell histiocytosis (LCH) characterized by abnormal proliferation of Langerhans cells in the stomach without systemic involvement, is rare; therefore, the clinical characteristics and outcomes of LCH remain unclear. We investigated the clinical characteristics and outcomes in patients diagnosed with localized gastric LCH and have also discussed treatment strategies for this rare disease. Methods The study included seven patients diagnosed with localized gastric LCH at our hospital between September 1997 and December 2023. We retrospectively reviewed medical records and analyzed the clinicopathological characteristics and patient outcomes. Results Endoscopically, localized gastric LCH appeared as a small erosion in the distal part of the stomach. Positron emission tomography-computed tomography revealed normal findings in 100.0% (4/4) of patients during pre-treatment workup. Immunohistochemical analysis using S-100 and CD1a showed immunopositive cells in all tested patients. Of the six patients who underwent follow-up, two (33.3%) showed metachronous recurrence at a location distinct from the initial site. However, all patients eventually showed spontaneous regression of the disease, and no gastric LCH-induced mortality was observed during follow-up. Conclusions Careful and regular surveillance may be sufficient for patients with localized gastric LCH without systemic involvement.

Abstract 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.