Different modifiable risk factors for the development of non-advanced adenoma, advanced adenomatous lesion, and sessile serrated lesions, on screening colonoscopy.

The development of premalignant colorectal polyps is significantly influenced by various lifestyle and modifiable risk factors. In our study, we used a large cohort of 9025 patients, who underwent screening colonoscopies at a university hospital, to assess the risk factors associated with the development of three different colorectal cancer precursor lesions: non-advanced adenomas (NAs), advanced adenomatous lesions (ADLs), and sessile serrated lesions (SSLs). Among the participants, 3641 had NAs, 836 had ADLs, and 533 had SSLs. We identified obesity, current smoking, and appendicular skeletal muscle mass as modifiable lifestyle risk factors that increase the development of NAs and ADLs (all P < 0.05). Furthermore, we found a positive correlation between the degree of obesity and an increased risk of developing NAs and ADLs (all P for trend < 0.001), while non-smoking was associated with a decreased risk (P for trend < 0.001 and 0.003, respectively). Smoking was the only modifiable risk factor for developing SSLs (adjusted odds ratio [aOR] 1.58; 95% confidence interval [CI] 1.20-2.07), and the risk was even higher in patients with metabolic syndrome (aOR 1.71; 95% CI 1.05-2.77). Addressing modifiable lifestyle factors such as smoking and obesity could play an important role in reducing the risk of both non-advanced and advanced adenomatous lesions. Smoking cessation is especially important as it is a significant modifiable risk factor for sessile serrated lesions.

[IDEN Consensus on Management of Antithrombotic Agents in Patients Undergoing Gastrointestinal Endoscopy].

Antithrombotic agents, including antiplatelet agent and anticoagulants are widely used in Korea due to increasing incidence of cardio-cerebrovascular disease and aging population. The management of patients using antithrombotic agents during endoscopic procedures is an important clinical challenge. Clinical practice guideline regarding this issue which was developed by the Korean Society of Gastrointestinal Endoscopy was published in 2020. However, since then, new evidence has emerged for the use of dual antiplatelet therapy and direct anticoagulant management, and revised guidelines were issued in the US and Europe. Accordingly, the previous guidelines were revised, cardiologists also participated in the development group, and the recommendations went through a consensus process among international experts. This guideline presents 14 recommendations made according to the Grading of Recommendations, Assessment, Development, and Evaluation methodology, and was reviewed by multidisciplinary experts. This guideline provides useful information that can assist endoscopists in the management of patients on antithrombotic agents who require diagnostic and elective therapeutic endoscopy. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

Efficacy of Tegoprazan in Patients With Functional Dyspepsia: A Prospective, Multicenter, Single-arm Study.

Background/Aims: Acid-suppressive drugs, such as proton pump inhibitors (PPIs), are treatment options for functional dyspepsia (FD). However, the efficacy of potassium-competitive acid blockers (P-CABs) in treating FD has not yet been established. This prospective multicenter clinical trial-based study aimed to assess the efficacy and safety of tegoprazan as a P-CAB treatment in patients with FD. Methods: FD was diagnosed using the Rome IV criteria. All patients received tegoprazan 50 mg once daily for 8 weeks. Dyspeptic symptoms were assessed using a dyspepsia symptom questionnaire (5-point Likert scale, Nepean Dyspepsia Index-Korean [NDI-K], and gastroesophageal reflux disease-health-related quality of life [GERD-HRQL]). The main outcome was satisfactory symptom relief rates at 8 weeks. Results: In this study, from the initial screening of 209 patients, 173 were included in the per-protocol set analysis. Satisfactory symptom relief rates at 8 and 4 weeks were 86.7% and 74.6%, respectively. In addition, the NDI-K and GERD-HRQL scores significantly improved at 8 and 4 weeks compared with the baseline scores. The efficacy of tegoprazan was not influenced by the FD subtype or Helicobacter pylori status. In patients with overlapping FD and GERD, there was a greater improvement in the NDI-K and GERD-HRQL scores than in patients with FD symptoms only. No serious drug-related adverse events occurred during this study. Conclusion: Tegoprazan (50 mg) administered once daily provided satisfactory symptom relief for FD.

International Digestive Endoscopy Network consensus on the management of antithrombotic agents in patients undergoing gastrointestinal endoscopy.

Antithrombotic agents, including antiplatelet agents and anticoagulants, are widely used in Korea because of the increasing incidence of cardiocerebrovascular disease and the aging population. The management of patients using antithrombotic agents during endoscopic procedures is an important clinical challenge. The clinical practice guidelines for this issue, developed by the Korean Society of Gastrointestinal Endoscopy, were published in 2020. However, new evidence on the use of dual antiplatelet therapy and direct anticoagulant management has emerged, and revised guidelines have been issued in the United States and Europe. Accordingly, the previous guidelines were revised. Cardiologists were part of the group that developed the guideline, and the recommendations went through a consensus-reaching process among international experts. This guideline presents 14 recommendations made based on the Grading of Recommendations, Assessment, Development, and Evaluation methodology and was reviewed by multidisciplinary experts. These guidelines provide useful information that can assist endoscopists in the management of patients receiving antithrombotic agents who require diagnostic and elective therapeutic endoscopy. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

Clinical Trial: Efficacy of Mosapride Controlled-release and Nortriptyline in Patients With Functional Dyspepsia: A Multicenter, Double-placebo, Double-blinded, Randomized Controlled, Parallel Clinical Study.

Background/Aims: Prokinetic agents and neuromodulators are among the treatment options for functional dyspepsia (FD), but their comparative efficacy is unclear. We aimed to compare the efficacy of mosapride controlled-release (CR) and nortriptyline in patients with FD after 4 weeks of treatment. Methods: Participants with FD were randomly assigned (1:1) to receive mosapride CR (mosapride CR 15 mg and nortriptyline placebo) or nortriptyline (mosapride CR placebo and nortriptyline 10 mg) in double-placebo, double-blinded, randomized controlled, parallel clinical study. The primary endpoint was defined as the proportion of patients with overall dyspepsia improvement after 4 weeks treatment. The secondary endpoints were changes in individual symptom scores, anxiety, depression, and quality of life. Results: One hundred nine participants were recruited and assessed for eligibility, and 54 in the mosapride CR group and 50 in the nortriptyline group were included in the modified intention-to-treat protocol. The rate of overall dyspepsia improvement was similar between groups (53.7% vs 54.0%, P = 0.976). There was no difference in the efficacy of mosapride CR and nortriptyline in a subgroup analysis by FD subtype (59.3% vs 52.5% in postprandial distress syndrome, P = 0.615; 44.4% vs 40.0% in epigastric pain syndrome, P = > 0.999; 50.0% vs 59.1% in overlap, P = 0.565; respectively). Both treatments significantly improved anxiety, depression, and quality of life from baseline. Conclusion: Mosapride CR and nortriptyline showed similar efficacy in patients with FD regardless of the subtype. Both treatments could be equally helpful for improving quality of life and psychological well-being while also relieving dyspepsia.

Clinical Practice Guideline for Percutaneous Endoscopic Gastrostomy.

With an aging population, the number of patients with difficulty swallowing due to medical conditions is gradually increasing. In such cases, enteral nutrition is administered through a temporary nasogastric tube. Long-term use of a nasogastric tube leads to various complications and a decreased quality of life. Percutaneous endoscopic gastrostomy (PEG) is the percutaneous placement of a tube into the stomach, aided endoscopically, which may be an alternative to a nasogastric tube when enteral nutritional is required for 4 weeks or more. This paper is the first Korean clinical guideline for PEG. It was developed jointly by the Korean College of Helicobacter and Upper Gastrointestinal Research and led by the Korean Society of Gastrointestinal Endoscopy. These guidelines aimed to provide physicians, including endoscopists, with the indications, use of prophylactic antibiotics, timing of enteric nutrition, tube placement methods, complications, replacement, and tubes removal for PEG based on the currently available clinical evidence.

[Clinical Practice Guideline for Percutaneous Endoscopic Gastrostomy].

With an aging population, the number of patients with difficulty in swallowing due to medical conditions is gradually increasing. In such cases, enteral nutrition is administered through a temporary nasogastric tube. However, the long-term use of a nasogastric tube leads to various complications and a decreased quality of life. Percutaneous endoscopic gastrostomy (PEG) is the percutaneous placement of a tube into the stomach that is aided endoscopically and may be an alternative to a nasogastric tube when enteral nutritional is required for four weeks or more. This paper is the first Korean clinical guideline for PEG developed jointly by the Korean College of Helicobacter and Upper Gastrointestinal Research and led by the Korean Society of Gastrointestinal Endoscopy. These guidelines aimed to provide physicians, including endoscopists, with the indications, use of prophylactic antibiotics, timing of enteric nutrition, tube placement methods, complications, replacement, and tubes removal for PEG based on the currently available clinical evidence.

Clinical practice guidelines for percutaneous endoscopic gastrostomy.

With an aging population, the number of patients with difficulty in swallowing due to medical conditions is gradually increasing. In such cases, enteral nutrition is administered through a temporary nasogastric tube. However, the long-term use of a nasogastric tube leads to various complications and a decreased quality of life. Percutaneous endoscopic gastrostomy (PEG) is the percutaneous placement of a tube into the stomach that is aided endoscopically and may be an alternative to a nasogastric tube when enteral nutritional is required for four weeks or more. This paper is the first Korean clinical guideline for PEG developed jointly by the Korean College of Helicobacter and Upper Gastrointestinal Research and led by the Korean Society of Gastrointestinal Endoscopy. These guidelines aimed to provide physicians, including endoscopists, with the indications, use of prophylactic antibiotics, timing of enteric nutrition, tube placement methods, complications, replacement, and tube removal for PEG based on the currently available clinical evidence.

Erratum: Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach.

This corrects the article on p. 3 in vol. 23, PMID: 36750993.

Clinical Practice Guideline for Gastritis in Korea.

Gastritis is a disease characterized by inflammation of the gastric mucosa. It is very common and has various classification systems such as the updated Sydney system. As there is a lot of evidence that Helicobacter pylori infection is associated with the development of gastric cancer and that gastric cancer can be prevented by eradication, H. pylori gastritis has been emphasized recently. The incidence rate of gastric cancer in Korea is the highest in the world, and due to the spread of screening endoscopy, atrophic gastritis and intestinal metaplasia are commonly diagnosed in the general population. However, there have been no clinical guidelines developed in Korea for these lesions. Therefore, this clinical guideline has been developed by the Korean College of Helicobacter and Upper Gastrointestinal Research for important topics that are frequently encountered in clinical situations related to gastritis. Evidence-based guidelines were developed through systematic review and de novo processes, and eight recommendations were made for eight key questions. This guideline needs to be periodically revised according to the needs of clinical practice or as important evidence about this issue is published in the future.

Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach.

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Rehabilitation Program for Improved Musculoskeletal Pain in Gastrointestinal Endoscopists: Multicenter Prospective Cohort Study.

Background/Aims: This study aimed to develop a rehabilitation program for musculoskeletal pain experienced by gastrointestinal endoscopists and to investigate its usefulness. Methods: This was a multicenter cohort study. During the first 2 weeks, a questionnaire regarding daily workload and musculoskeletal symptoms was administered. Then, a rehabilitation program including equipment/posture correction and stretching was conducted during the remaining 6 weeks. Follow-up daily workload and musculoskeletal symptom surveys were distributed during the last 2 weeks. The program satisfaction survey was performed at the 6th and 8th weeks. Results: Among 118 participants (69 men), 94% (n=111) complained of musculoskeletal pain at baseline. Various hospital activities at baseline were associated with multisite musculoskeletal pain, whereas only a few workloads were correlated with musculoskeletal pain after the rehabilitation program. Follow-up musculoskeletal pain was negatively correlated with equipment/posture program performance; arm/elbow pain was negatively correlated with elbow (R=-0.307) and wrist (R=-0.205) posture; leg/foot pain was negatively correlated with monitor position, shoulder, elbow, wrist, leg, and foot posture. Higher performance in the scope position (86.8% in the improvement vs 71.3% in the aggravation group, p=0.054) and table height (94.1% vs 79.1%, p=0.054) were associated with pain improvement. An increased number of colonoscopy procedures (6.27 in the aggravation vs 0.02 in the improvement group, p=0.017) was associated with pain aggravation. Most participants reported being average (32%) or satisfied (67%) with the program at the end of the study. Conclusions: Our rehabilitation program is easily applicable, satisfactory, and helpful for improving the musculoskeletal pain experienced by gastrointestinal endoscopists.

A Case of Intramural Gastric Wall Abscess, a Rare Disease Successfully Treated with Endoscopic Incision and Drainage.

Gastric wall abscess is a rare condition characterized by a purulent inflammatory process resulting in the formation of a pocket of pus in the stomach. As the mucosa is usually intact, it requires various tools such as endoscopic ultrasonography or computed tomography for the differential diagnosis to rule out more common subepithelial tumors. Even after the diagnosis, the treatment for gastric wall abscess was previously restricted to surgical resection in combination with antibiotics. Currently, in order to avoid unnecessary surgery, the alternative method of initial treatment with an endoscopic approach is recommended. It also helps to choose appropriate antibiotics with confirmation of the pathogen by drainage. There are few reports that describe the detailed processing of the endoscopic drainage, and there is no consensus on the treatment. The pathogens that cause gastric wall abscess are usually Streptococci, Staphylococci, and Escherichia coli. There is only one case reported to be caused by Candida albicans. This is the first report of Elizabethkingia anopheles as the pathogen of the gastric wall abscess. Here, we report a case of gastric wall abscess in a 75-year-old man, safely treated by endoscopic drainage and antibiotics, confirmed by isolating the contents of the abscess.

Korean practice guidelines for gastric cancer 2022: an evidence-based, multidisciplinary approach

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Clinical outcomes of acute upper gastrointestinal bleeding according to the risk indicated by Glasgow-Blatchford risk score-computed tomography score in the emergency room.

BACKGROUND/AIMS: Acute upper gastrointestinal (UGI) bleeding is a significant emergency situation with a mortality rate of 2% to 10%. Therefore, initial risk stratification is important for proper management. We aimed to evaluate the role of contrast-enhanced multidetector computed tomography (MDCT) for risk stratification in patients with acute UGI bleeding in the emergency room (ER). METHODS: This retrospective study included patients with UGI bleeding in the ER. Glasgow-Blatchford risk score-computed tomography (GBS-CT) was assessed using a combination of GBS and the MDCT scan scoring system. RESULTS: Of the 297 patients with UGI bleeding, 124 (41.8%) underwent abdominal MDCT. Among them, 90.3% were classified as high-risk by GBS, and five patients died (4.0%). Rebleeding occurred in nine patients (7.3%). The high-risk GBS-CT group had significantly higher in-hospital mortality (10.5% in high-risk vs. 1.4% in moderate risk vs. 0% in low-risk, p = 0.049), transfusion amount (p < 0.001), and endoscopic hemostasis (p < 0.001) compared to the moderate- and low-risk groups. CONCLUSION: Adding MDCT scans to the existing validated prognosis model when predicting the risk of UGI bleeding in patients in the ER plays a significant role in determining in-hospital mortality, transfusions, and the need for endoscopic hemostasis.

Association Between Gut Regulatory Hormones and Post-operative Weight Loss Following Gastrectomy in Patients With Gastric Cancer.

Background/Aims: Post-operative weight loss in patients with gastric cancer lead to a poor quality of life and long-term survival. This study aims to evaluate the effects of gut regulatory hormones on post-operative weight loss in patients with subtotal gastrectomy for gastric cancer. Methods: This prospective study was conducted for 12 months post-surgery in 14 controls and 13 gastrectomy patients who underwent subtotal gastrectomy for gastric cancer. Serum plasma ghrelin, glucagon-like peptide-1, gastric inhibitory peptide-1, peptide YY, insulin, and homeostatic model assessment for insulin resistance responses to a standardized test meal were recorded at multiple time points before and after gastrectomy at 4 and 12 months. Results: The mean weight difference between the pre-operative state and the 4-month period was significantly reduced to 6.6 kg (P = 0.032), but significant weight reduction was not observed from 4 months to 12 months. The plasma levels of glucagon-like peptide-1, gastric inhibitory peptide-1, and peptide YY were significantly increased 4 months postoperatively compared to the pre-operative state (all P = 0.035); however, pre-operative levels and relative changes over a period of 0-4 months of hormones were not correlated with body weight changes. Only the pre-operative ghrelin at peak had a negative correlation with changes in weight reduction in the 4 months after surgery (ρ = -0.8, P = 0.024). Conclusions: Significant weight reduction was common after subtotal gastrectomy for gastric cancer with a negative correlation pre-operative plasma ghrelin levels. Incretin hormones are modestly but significantly increased after subtotal gastrectomy; however, these changes did not affect the weight changes.

Perspectives of East Asian patients and physicians on complementary and alternative medicine use for inflammatory bowel disease: results of a cross-sectional, multinational study.

BACKGROUND/AIMS: Complementary and alternative medicine (CAM) is prevalent in East Asia. However, information on CAM in East Asian patients with inflammatory bowel disease (IBD) is scarce. We aimed to profile the prevalence and pattern of CAM use among East Asian IBD patients and to identify factors associated with CAM use. We also compared physicians' perspectives on CAM. METHODS: Patients with IBD from China, Japan, and South Korea were invited to complete questionnaires on CAM use. Patient demographic and clinical data were collected. Logistic regression analysis was applied for predictors of CAM use. Physicians from each country were asked about their opinion on CAM services or products. RESULTS: Overall, 905 patients with IBD participated in this study (China 232, Japan 255, and South Korea 418). Approximately 8.6% of patients with IBD used CAM services for their disease, while 29.7% of patients sought at least 1 kind of CAM product. Current active disease and Chinese or South Korean nationality over Japanese were independent predictors of CAM use. Chinese doctors were more likely to consider CAM helpful for patients with IBD than were Japanese and South Korean doctors. CONCLUSIONS: In 8.6% and 29.7% of East Asian patients with IBD used CAM services and products, respectively, which does not differ from the prevalence in their Western counterparts. There is a significant gap regarding CAM usage among different Asian countries, not only from the patients' perspective but also from the physicians' point of view.

On-demand Versus Continuous Maintenance Treatment of Gastroesophageal Reflux Disease With Proton Pump Inhibitors: A Systematic Review and Meta-analysis.

BACKGROUND/AIMS: Long-term maintenance treatment of gastroesophageal reflux disease (GERD) is commonly used to prevent relapse of reflux symptoms; however, due to concerns about safety of long-term proton pump inhibitors (PPI) use, on-demand therapy is recommended as a longterm treatment modality. We compared the efficacy of on-demand and continuous PPI therapy for maintenance treatment of patients with GERD using meta-analysis. METHODS: Core electronic databases were searched for randomized controlled trials comparing on-demand and continuous therapy in GERD patients. The primary outcome was treatment failure of maintenance therapy, and the secondary outcomes included symptomatic relief, patient satisfaction, and amount of PPI use. RESULTS: Overall, 11 studies were selected in the systematic review and meta-analysis. Compared with continuous PPI therapy, on-demand therapy showed similar outcomes for treatment failure (risk ratio, 1.26; 95% confidence interval [CI], 0.76-2.07), particularly in the non-erosive esophageal reflux disease and mild erosive reflux disease group (risk ratio, 1.48; 95% CI, 0.39-5.63). In studies including severe esophagitis patients, continuous PPI maintenance treatment was more effective (ß, 0.127 [95% CI, 0.066-0.188]; P < 0.001). Severity of esophagitis was associated with higher efficacies of continuous maintenance therapy. The amount of daily PPI use was about half in the on-demand group compared to the continuous group (risk difference -0.52; 95% CI, -0.62--0.42). CONCLUSIONS: On-demand PPI therapy shows comparable efficacy to the continuous maintenance treatment in the non-erosive esophageal reflux disease and mild erosive reflux disease group, and can remarkably reduce the amount of PPI use. Therefore, on-demand therapy may be preferentially recommended in the maintenance treatment of GERD unaccompanied by severe esophagitis.

Development and Validity Assessment of a Self-evaluation Questionnaire for Functional Dyspepsia: A Multicenter Prospective Study in Korea.

BACKGROUND/AIMS: Patient-reported outcomes (PROs) are essential for clinical decision making, conduction of clinical research, and drug application acquisition in functional gastrointestinal disorders. The aim of this study is to develop a PRO instrument and to determine the respondents' perception of the efficacy of therapeutic agents for functional dyspepsia (FD). METHODS: A self-evaluation questionnaire for dyspepsia (SEQ-DYSPEPSIA) was developed and validated through a structured process. The 2-week reproducibility was evaluated, and the construct validity was assessed by correlating the scores of SEQ-DYSPEPSIA (including typical and major FD symptom subscales). Finally, the response to medication was assessed by comparing the changes after 4 weeks of treatment. RESULTS: A total of 193 Korean patients (age 48.5 ± 13.6 years, 69.4% women) completed the questionnaire. SEQ-DYSPEPSIA with 11 items had a good internal consistency (alpha = 0.770-0.905) and an acceptable test-retest reliability (intraclass correlation coefficient = 0.733-0.859). The self-evaluation questionnaire (SEQ)-major FD score highly correlated with the postprandial fullness/early satiety domain of the Patient Assessment of Gastrointestinal Symptom Severity Index (correlation coefficient r = 0.741, P < 0.001), Nepean Dyspepsia Index-Korean version (NDI-K) (r = 0.839, P < 0.001), and NDI-K quality of life (r = -0.275 to -0.344, P < 0.001). After medical treatment, decrease in the SEQ-typical FD and SEQ-major FD was significantly greater in the responder group than in nonresponder group (P = 0.019 and P = 0.009, respectively). CONCLUSION: This study suggests that the Korean version of SEQ-DYSPEPSIA has good reliability and validity, and can be a useful PRO measurement tool in patients with FD.

Prediction model for curative endoscopic submucosal dissection of undifferentiated-type early gastric cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) is an effective treatment for early gastric cancer (EGC); however, its curative resection rate is low for undifferentiated-type EGC. We developed and externally validated a prediction model for curative ESD of undifferentiated-type EGC. METHODS: In this cross-sectional study, we included 448 patients who underwent ESD for undifferentiated-type EGC at 18 hospitals in Korea between 2005 and 2015 in the development cohort and 1342 patients who underwent surgery at two hospitals in the validation cohort. A prediction model was developed using the logistic regression model. RESULTS: Endoscopic tumor size 1-2 cm (odds ratio [OR], 2.40; 95% confidence interval [CI] 1.54-3.73), tumor size > 2 cm (OR, 14.00; 95% CI 6.81-28.77), and proximal tumor location from the lower to upper third of the stomach (OR, 1.45; 95% CI 1.03-2.04) were independent predictors of non-curative ESD. A six-score prediction model was developed by assigning points to endoscopic tumor size > 2 cm (five points), tumor size 1-2 cm (two points), upper third location (two points), and middle third location (one point). The rate of curative ESD ranged from 70.6% (score 0) to 11.6% (score 5) with an area under the receiver operating characteristic curve (AUC) of 0.720 (95% CI 0.673-0.766). The model also showed good performance in the validation cohort (AUC, 0.775; 95% CI 0.748-0.803). CONCLUSIONS: This six-score prediction model may help in predicting curative ESD and making informed decisions about the treatment selection between ESD and surgery for undifferentiated-type EGC.