Objectives. Endoscopic resection (ER) is commonly performed to treat gastric epithelial neoplasms and subepithelial tumors. The aim of this study was to predict the risk factors for surgery after ER-induced perforation. Methods. We retrospectively reviewed the data on patients who received gastric endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) between January 2010 and March 2015. Patients who were confirmed to have perforation were classified into surgery and nonsurgery groups. We aimed to determine the risk factors for surgery in patients who developed iatrogenic gastric perforations. Results. A total of 1183 patients underwent ER. Perforation occurred in 69 (5.8%) patients, and 9 patients (0.8%) required surgery to manage the perforation. In univariate analysis, anterior location of the lesion, a subepithelial lesion, two or more postprocedure pain killers within 24 hrs, and increased heart rate within 24 hrs after the procedure were the factors related to surgery. In logistic regression analysis, the location of the lesion at the anterior wall and using two or more postprocedure pain killers within 24 hrs were risk factors for surgery. Conclusion. Most cases of perforations after ER can be managed conservatively. When a patient requires two or more postprocedure pain killers within 24 hrs and the lesion is located on the anterior wall, early surgery should be considered instead of conservative management.

Background/Aims: The rate of nonneoplastic pathology (NNP) after endoscopic resection (ER) of gastric epithelial neoplasia (GEN) has been reported to be 3%-7%. However, to date, the associations of pretreatment characteristics with NNP have not been identified. The aim of this study was to develop a predictive model for NNP after ER. Methods: Among 817 patients who underwent ER for GEN, factors associated with NNP were identified by univariate and multivariate analyses. Weighted points considering the β coefficient were allocated to each variable that was significant in the multivariate analysis. The predictive score was calculated by the total points. The area under the receiver operating characteristic curve (AUROC) was calculated for the predictive score. Results: The rate of NNP was 8.8%. After multivariate analysis, poor demarcation from the background, no ulceration, a flat appearance, and low-grade dysplasia were significant factors predictive of NNP. One point each was allocated for no ulcer, flat appearance, and low-grade dysplasia. Two points were allocated for poor demarcation from the background. The predictive score ranged from 0 to 5 points. Patients were categorized as being at low risk (0, 1, or 2 points) or high risk (3, 4, or 5 points) for NNP. The AUROC was 0.82 (95% confidence interval, 0.77 to 0.88; p<0.01). With a cutoff value of 2.5, the sensitivity and specificity of the score for predicting NNP were 0.72 and 0.84, respectively. Conclusions: We developed a model to predict NNP after ER. Endoscopic re-biopsy or re-evaluation by pathologists is strongly recommended for the high-risk group. (Gut Liver 2020;14:199-206)