Helicobacter pylori, Homologous-Recombination Genes, and Gastric Cancer.

BACKGROUND: Helicobacter pylori infection is a well-known risk factor for gastric cancer. However, the contribution of germline pathogenic variants in cancer-predisposing genes and their effect, when combined with H. pylori infection, on the risk of gastric cancer has not been widely evaluated. METHODS: We evaluated the association between germline pathogenic variants in 27 cancer-predisposing genes and the risk of gastric cancer in a sample of 10,426 patients with gastric cancer and 38,153 controls from BioBank Japan. We also assessed the combined effect of pathogenic variants and H. pylori infection status on the risk of gastric cancer and calculated the cumulative risk in 1433 patients with gastric cancer and 5997 controls from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC). RESULTS: Germline pathogenic variants in nine genes (APC, ATM, BRCA1, BRCA2, CDH1, MLH1, MSH2, MSH6, and PALB2) were associated with the risk of gastric cancer. We found an interaction between H. pylori infection and pathogenic variants in homologous-recombination genes with respect to the risk of gastric cancer in the sample from HERPACC (relative excess risk due to the interaction, 16.01; 95% confidence interval [CI], 2.22 to 29.81; P = 0.02). At 85 years of age, persons with H. pylori infection and a pathogenic variant had a higher cumulative risk of gastric cancer than noncarriers infected with H. pylori (45.5% [95% CI, 20.7 to 62.6] vs. 14.4% [95% CI, 12.2 to 16.6]). CONCLUSIONS: H. pylori infection modified the risk of gastric cancer associated with germline pathogenic variants in homologous-recombination genes. (Funded by the Japan Agency for Medical Research and Development and others.).

Artificial intelligence using deep learning analysis of endoscopic ultrasonography images for the differential diagnosis of pancreatic masses.

BACKGROUND : There are several types of pancreatic mass, so it is important to distinguish between them before treatment. Artificial intelligence (AI) is a mathematical technique that automates learning and recognition of data patterns. This study aimed to investigate the efficacy of our AI model using endoscopic ultrasonography (EUS) images of multiple types of pancreatic mass (pancreatic ductal adenocarcinoma [PDAC], pancreatic adenosquamous carcinoma [PASC], acinar cell carcinoma [ACC], metastatic pancreatic tumor [MPT], neuroendocrine carcinoma [NEC], neuroendocrine tumor [NET], solid pseudopapillary neoplasm [SPN], chronic pancreatitis, and autoimmune pancreatitis [AIP]). METHODS : Patients who underwent EUS were included in this retrospective study. The included patients were divided into training, validation, and test cohorts. Using these cohorts, an AI model that can distinguish pancreatic carcinomas from noncarcinomatous pancreatic lesions was developed using a deep-learning architecture and the diagnostic performance of the AI model was evaluated. RESULTS : 22 000 images were generated from 933 patients. The area under the curve, sensitivity, specificity, and accuracy (95 %CI) of the AI model for the diagnosis of pancreatic carcinomas in the test cohort were 0.90 (0.84-0.97), 0.94 (0.88-0.98), 0.82 (0.68-0.92), and 0.91 (0.85-0.95), respectively. The per-category sensitivities (95 %CI) of each disease were PDAC 0.96 (0.90-0.99), PASC 1.00 (0.05-1.00), ACC 1.00 (0.22-1.00), MPT 0.33 (0.01-0.91), NEC 1.00 (0.22-1.00), NET 0.93 (0.66-1.00), SPN 1.00 (0.22-1.00), chronic pancreatitis 0.78 (0.52-0.94), and AIP 0.73 (0.39-0.94). CONCLUSIONS : Our developed AI model can distinguish pancreatic carcinomas from noncarcinomatous pancreatic lesions, but external validation is needed.

Long-Term Outcome of Patients with Locally Advanced Clinically Unresectable Esophageal Cancer Undergoing Conversion Surgery after Induction Chemotherapy with Docetaxel Plus Cisplatin and 5-Fluorouracil.

BACKGROUND: Although definitive chemoradiotherapy (CRT) is recommended for patients with locally advanced unresectable esophageal cancer, the outcome is unsatisfactory. We previously demonstrated the safety and efficacy of induction chemotherapy with docetaxel plus cisplatin and 5-fluorouracil (DCF) and subsequent conversion surgery (CS) for patients with locally advanced unresectable esophageal cancer. However, whether or not induction DCF chemotherapy and subsequent CS improve the long-term outcomes of patients with locally advanced unresectable esophageal cancer is unclear. METHODS: A total of 177 consecutive patients with locally advanced unresectable esophageal cancer without distant metastasis were included in this study. Of these, 55 patients received DCF induction chemotherapy, of whom 36 underwent CS. We divided these 36 patients into two groups according to clinical response, which was analyzed retrospectively. RESULTS: The toxicities related to DCF chemotherapy were manageable. The response rate to induction DCF chemotherapy was 67%. R0 resection was achieved in 81% of the 36 patients who underwent subsequent CS. No serious postoperative complications were observed. Histopathological CR was achieved in 17% of the 36 patients, and the 3- and 5-year survival rates after CS were 61% and 54%, respectively. The outcomes of the patients who obtained good clinical response was better than the outcomes of patients who did not. CONCLUSIONS: Induction DCF chemotherapy and subsequent CS show acceptable toxicity and offer the chance of long-term survival in patients with locally advanced clinically unresectable esophageal cancer.

A nonrandomized, single-arm confirmatory trial of expanded endoscopic submucosal dissection indication for undifferentiated early gastric cancer: Japan Clinical Oncology Group study (JCOG1009/1010).

BACKGROUND: While endoscopic submucosal dissection (ESD) is recognized as a minimally invasive standard treatment for differentiated early gastric cancers (EGCs), it has not been indicated for undifferentiated EGC (UD-EGC) because of a relatively high risk of lymph node metastasis (LNM). However, patients with surgically resected mucosal (cT1a) UD-EGC ≤ 2 cm in size with no lymphovascular invasion or ulceration are reported to be at a very low risk of LNM. This multicenter, single-arm, confirmatory trial was conducted to evaluate the efficacy and safety of ESD for UD-EGC. METHODS: The key eligibility criteria were endoscopically diagnosed cT1a/N0/M0, single primary lesion, size ≤ 2 cm, no ulceration and histologically proven components of undifferentiated adenocarcinoma on biopsy. Based on the histological findings after ESD, additional gastrectomy was indicated if the criteria for curative resection were not satisfied. The subjects of the primary analysis were patients with UD-EGC as the dominant component. The primary endpoint was 5-year overall survival (OS) of patients with UD-EGC. RESULTS: Three hundred 46 patients were enrolled from 49 institutions. The proportion of en bloc resection was 99%. No ESD-related Grade 4 adverse events were noted. Delayed bleeding and intraoperative and delayed perforation occurred in 25 (7.3%), 13 (3.8%), and 6 (1.7%) patients, respectively. Among the 275 patients who were the subjects of the primary analysis, curative resection was achieved in 195 patients (71%), and 5-year OS was 99.3% (95% CI: 97.1-99.8). CONCLUSIONS: ESD can be a curative and less invasive treatment for UD-EGC for patients meeting the eligibility criteria of this study.

Variations in clinical features and oncologic behaviors of T1 colorectal cancer according to tumor location.

BACKGROUND: Different genetic characteristics according to tumor location result in variations in survival rates and treatment responses in advanced colorectal cancer (CRC). However, the effects of tumor location during early CRC are still unclear. METHODS: Patients with T1 CRC treated between 2003 and 2019 were enrolled from a prospectively collected database. Patients were once divided into four groups, then combined into two groups (right- and left-sided CRC) according to the tumor location, and clinical features and oncologic behaviors were compared. RESULTS: In total, 458 patients were analyzed. Right-sided CRC had a lower incidence of polypoid type tumor than left-sided CRC (36/126 (28.6%) vs 186/332 (56.0%), p < 0.001). There were no differences in tumor size, pathological grade, pT1 substage and lymphovascular invasion between right- and left-sided CRC. Overall, lymph nodal involvement was observed in 42/458 (9.1%) patients. Right-sided CRC had a lower rate of patients with lymph nodal involvement than left-sided CRC (6/126 (4.8%) vs 36/332 (10.8%), p = 0.04). CONCLUSION: The present study revealed that there were significant differences in the macroscopic type and the incidence of lymph node involvement between right- and left-sided CRC. The clinical features and oncologic behaviors of T1 CRC are possible to vary according to tumor location.

Risk factor analysis for adverse events and stent dysfunction of endoscopic ultrasound-guided choledochoduodenostomy.

BACKGROUND AND AIMS: Although the technique of endoscopic ultrasound-guided choledochoduodenostomy (EUS-CDS) is becoming standardized, its safety issues have not been sufficiently investigated. Therefore, we aimed to identify factors associated with adverse events and stent patency in EUS-CDS. METHODS: Consecutive patients who underwent EUS-CDS between September 2003 and July 2017 were included. Technical/clinical success, adverse events and stent dysfunctions were analyzed retrospectively. RESULTS: A total of 151 patients underwent EUS-CDS. In nine patients, procedures were discontinued before puncture. Technical and clinical success rates were 96.5% (137/142) and 98.5% (135/137), respectively. The adverse event rate was 20.4% (29/142). As a risk factor for peritonitis, plastic stents (PS) showed a significantly high odds ratio (OR) compared with covered self-expandable metal stents (CSEMS; OR, 4.31; P = 0.030). CSEMS cases showed a significantly longer patency period than PS cases (329 vs 89 days; HR, 0.35; P < 0.001). As a risk factor for early stent dysfunction (within 14 days), stent direction to the oral side showed a significantly high OR (OR, 43.47; P < 0.001). In cases with oblique-viewing EUS, double penetration of the duodenum occurred at significantly higher frequency than in cases with forward-viewing EUS (7.0 vs 0.0%; P = 0.024). CONCLUSIONS: Plastic stents and stent direction to the oral side were risk factors for peritonitis and early stent dysfunction, respectively. Using covered self-expandable metal stents and changing stent direction to the anal side seemed appropriate to prevent peritonitis and early stent dysfunction.

Features of chronic pancreatitis by endoscopic ultrasound influence the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration of small pancreatic lesions.

BACKGROUND AND AIM: In chronic pancreatitis (CP) patients, diagnosis of small pancreatic lesions by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is challenging. Thus, the aim of the present study was to investigate whether CP influences the diagnostic ability of EUS-FNA for pancreatic lesions ≤10 mm. METHODS: One hundred and seventeen patients who underwent EUS-FNA for pancreatic lesions ≤10 mm in size were enrolled. Patients were classified into two groups based on features of CP observed by EUS (EUS-CP features) in accordance with the Rosemont classification. The CP group was defined as cases consistent with CP or suggestive of CP, and the non-CP group was defined as cases indeterminate for CP or normal. Factors influencing the diagnostic accuracy of EUS-FNA and CP status in pancreatic tumors were also investigated. RESULTS: Diagnostic ability of EUS-FNA (overall cases, non-CP vs CP) had sensitivity (80.4%, 96.7% vs 57.1%; P < 0.001), specificity (100%, 100% vs 100%; P > 0.05), and accuracy (91.5%, 98.6% vs 80.4%; P = 0.001). In multivariate analysis of factors influencing the accuracy of EUS-FNA, CP significantly lowered the accuracy (P = 0.048; odds ratio [OR] = 9.21). Among pancreatic cancer patients, the number of CP patients was significantly higher than the number of patients with benign lesions (P = 0.023). In multivariate analysis, lobularity without honeycombing was more frequently observed in cases of pancreatic cancer (P = 0.018; OR, 12.65). CONCLUSION: Endoscopic ultrasound-guided FNA offers high accuracy for small pancreatic lesions ≤10 mm. However, in cases with CP, the diagnostic ability of EUS-FNA is significantly reduced.

GWAS analysis reveals a significant contribution of PSCA to the risk of Heliobacter pylori-induced gastric atrophy.

Although recent genome-wide association studies (GWASs) have identified genetic variants associated with Helicobacter pylori (HP)-induced gastric cancer, few studies have examined the genetic traits associated with the risk of HP-induced gastric precancerous conditions. This study aimed to elucidate genetic variants associated with these conditions using a genome-wide approach. Data from four sites of the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study were used in the discovery phase (Stage I); two datasets from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center 2 (HERPACC2) study were used in the replication phases (Stages II and III) and SKAT (SNP-set Kernel Association Test) and single variant-based GWASs were conducted for the risks of gastric atrophy (GA) and severe GA defined by serum pepsinogen (PG) levels, and PG1 and PG1/2 ratios. In the gene-based SKAT in Stage I, prostate stem cell antigen (PSCA) was significantly associated with the risks of GA and severe GA, and serum PG1/2 level by linear kernel [false discovery rate (FDR) = 0.011, 0.230 and 7.2 × 10-7, respectively]. The single variant-based GWAS revealed that nine PSCA single nucleotide polymorphisms (SNPs) fulfilled the genome-wide significance level (P < 5 × 10-8) for the risks of both GA and severe GA in the combined study, although most of these associations did not reach genome-wide significance in the discovery or validation cohort on their own. GWAS for serum PG1 levels and PG1/2 ratios revealed that the PSCA rs2920283 SNP had a striking P-value of 4.31 × 10-27 for PG1/2 ratios. The present GWAS revealed the genetic locus of PSCA as the most significant locus for the risk of HP-induced GA, which confirmed the recently reported association in Europeans.

Sex differences in the safety of S-1 plus oxaliplatin and S-1 plus cisplatin for patients with metastatic gastric cancer.

Previous studies have shown sex-related differences in the incidence of adverse events following treatment with fluoropyrimidines, however the mechanism of this difference is unknown. We examined sex-related differences in the safety of S-1 plus oxaliplatin (SOX) and S-1 plus cisplatin (CS) in 663 metastatic gastric cancer patients taking part in a phase III study. The incidences of leukopenia (odds ratio [OR] 1.9; P = .015), neutropenia (OR 2.2; P = .002), nausea (OR 2.0; P = .009), and vomiting (OR 2.8; P < .001) were increased in women versus men treated with SOX, while vomiting (OR 2.9; P < .001) and stomatitis (OR 1.8; P = .043) were increased in women versus men treated with CS. In contrast, male patients treated with CS experienced thrombocytopenia more often (OR 0.51; P = .009). The mean relative dose intensity of S-1 in SOX was 75.4% in women and 81.4% in men (P = .032). No difference in efficacy was observed between women and men undergoing either regimen. Sex-related differences in adverse reactions during SOX and CS treatment were confirmed in this phase III study. Further translational research studies are warranted to pursue the cause of this difference.

Early tumor shrinkage and depth of response in patients with advanced gastric cancer: a retrospective analysis of a randomized phase III study of first-line S-1 plus oxaliplatin vs. S-1 plus cisplatin.

BACKGROUND: We investigated early tumor shrinkage (ETS) and depth of response (DpR) using data from the G-SOX study comparing S-1 plus oxaliplatin with S-1 plus cisplatin as the first-line treatment for advanced gastric cancer (AGC). METHODS: ETS was determined as % decrease in the sum of the longest diameters of the target lesions at the first evaluation of week 6 compared to baseline. DpR was the maximum % shrinkage during the study treatment. The impact of ETS (cutoff value 20%) and DpR (continuous value) on progression-free survival (PFS) and overall survival (OS) were assessed by the log-rank test and Cox regression analysis including prognostic factors obtained in the G-SOX study; ECOG performance status, baseline sum of tumor diameters, disease status (recurrent/unresectable), and histology (diffuse/intestinal). RESULTS: Among 685 patients enrolled in the G-SOX study, 632 patients who had the first tumor evaluation were analyzed. Patients with ETS ≥ 20% had longer PFS (median 4.5 vs. 2.8 months, p < 0.0001) and OS (median 14.8 vs. 10.5 months, p < 0.0001) than those with ETS < 20%. Adjusted hazard ratios of ETS < 20 vs. ≥ 20% were 0.606 (95% confidence interval (CI) 0.506-0.725) for PFS and 0.589 (95% CI 0.492-0.704) for OS. DpR was also significantly associated with PFS and OS (both p < 0.0001). These results were similar between the SOX and CS groups. CONCLUSIONS: In AGC patients receiving the first-line therapy, ETS and DpR might be predictors for PFS and OS.

Usefulness of septal thickness measurement on endoscopic ultrasound as a predictor of malignancy of branched-duct and mixed-type intraductal papillary mucinous neoplasm of the pancreas.

BACKGROUND AND AIM: Septal thickness (ST) can predict a malignant branch-duct (BD) and mixed-type intraductal papillary mucinous neoplasm (IPMN) of the pancreas, but its cut-off value has not been established. The aim of the present study was to determine the optimal ST cut-off value to predict malignancy using endoscopic ultrasound (EUS). METHODS: We retrospectively identified 200 patients with IPMN, including 132 with BD- and mixed-IPMN, who underwent surgical resection between 1989 and 2017. ST was defined as the septum or lesion wall with the maximum diameter in BD- and mixed-IPMN. The possibility of ST as a malignant predictor was examined, as well as the diagnostic ability of ST combined with mural nodule (MN) height for malignant IPMN. RESULTS: Among the 132 IPMN patients, pathological diagnosis was benign in 81 (61.4%) and malignant in 51 (38.6%). Area under the curve for the diagnosis of malignancy using ST was 0.74 for pathological specimens, 0.70 for EUS and 0.56 for computed tomography. Multivariate analysis showed that the odds ratios for ST ≥2.5 mm and MN height ≥5 mm were 3.51 [95% confidence interval (CI), 1.55-7.97, P = 0.003] and 3.36 (95% CI, 1.52-7.45, P = 0.003), respectively. CONCLUSIONS: Septal thickness was an independent predictive factor similar to MN height for malignant IPMN in a multivariate analysis. The ST on EUS appeared to be the thickness of a fibrotic septum associated with the malignant transformation of IPMN. An ST cut-off value of 2.5 mm might provide an accurate prediction of malignant IPMN.

Short-term outcomes of multicenter prospective cohort study of gastric endoscopic resection: 'Real-world evidence' in Japan.

OBJECTIVES: A Japanese multicenter prospective cohort study examining endoscopic resection (ER) for early gastric cancer (EGC) has been conducted using a Web registry developed to determine the short-term and long-term outcomes based on absolute and expanded indications. We hereby present the short-term outcomes of this study. METHODS: All consecutive patients with EGC or suspected EGC undergoing ER at 41 participating institutions between July 2010 and June 2012 were enrolled and prospectively registered into the Web registry. The baseline characteristics were entered before ER, and the short-term outcomes were collected at 6 months following ER. RESULTS: Nine thousand six hundred and sixteen patients with 10 821 lesions underwent ER (endoscopic submucosal dissection [ESD]: 99.4%). The median procedure time was 76 min, and R0 resections were achieved for 91.6% of the lesions. Postoperative bleeding and intraoperative perforation occurred in 4.4% and 2.3% of the patients, respectively. Significant independent factors correlated with a longer procedure time (120 min or longer) were as follows: tumor size >20 mm, upper-third location, middle-third location, local recurrent lesion, ulcer findings, gastric tube, male gender, and submucosa. Histopathologically, 10 031 lesions were identified as common-type gastric cancers. The median tumor size was 15 mm. Noncurative resections were diagnosed for 18.3% of the lesions. Additional surgery was performed for 48.6% (824 lesions) of the 1695 noncurative ER lesions with a possible risk of lymph node (LN) metastasis. Among them, 64 (7.8%) exhibited LN metastasis. CONCLUSIONS: This multicenter prospective study showed favorable short-term outcomes for gastric ESD.

[Diagnosis of pancreatic neuroendocrine tumor led to diagnosis of multiple endocrine neoplasia type 1:a report of two cases].

Two cases of multiple endocrine neoplasia type 1 are reported. In both cases, computed tomography (CT) showed hypervascular lesions of the pancreas. Endoscopic ultrasound showed multiple lesions in the pancreas, and each case was diagnosed as pancreatic neuroendocrine tumor by EUS-FNA. In addition to a pancreatic neuroendocrine tumor, case 1 had hyperparathyroidism and case 2 had a history of parathyroid tumor. Furthermore, case 1 had a family history of pancreatic tumor and case 2 had a family history of pancreatic tumor and parathyroid resection. From these indications, multiple endocrine neoplasia type 1 was diagnosed by genetic testing. As demonstrated in these two cases, it is important to consider multiple endocrine neoplasia type 1 when diagnosing pancreatic neuroendocrine tumor.

Association between ALDH2 and ADH1B polymorphisms, alcohol drinking and gastric cancer: a replication and mediation analysis.

BACKGROUND: Aldehyde dehydrogenase 2 (ALDH2; rs671, Glu504Lys) and alcohol dehydrogenase 1B (ADH1B; rs1229984, His47Arg) polymorphisms have a strong impact on carcinogenic acetaldehyde accumulation after alcohol drinking. To date, however, evidence for a significant ALDH2-alcohol drinking interaction and a mediation effect of ALDH2/ADH1B through alcohol drinking on gastric cancer have remained unclear. We conducted two case-control studies to validate the interaction and to estimate the mediation effect on gastric cancer. METHODS: We calculated odds ratios (OR) and 95% confidence intervals (CI) for ALDH2/ADH1B genotypes and alcohol drinking using conditional logistic regression models after adjustment for potential confounding in the HERPACC-2 (697 cases and 1372 controls) and HERPACC-3 studies (678 cases and 678 controls). We also conducted a mediation analysis of the combination of the two studies to assess whether the effects of these polymorphisms operated through alcohol drinking or through other pathways. RESULTS: ALDH2 Lys alleles had a higher risk with increased alcohol consumption compared with ALDH2 Glu/Glu (OR for heavy drinking, 3.57; 95% CI 2.04-6.27; P for trend = 0.007), indicating a significant ALDH2-alcohol drinking interaction (Pinteraction = 0.024). The mediation analysis indicated a significant positive direct effect (OR 1.67; 95% CI 1.38-2.03) and a protective indirect effect (OR 0.84; 95% CI 0.76-0.92) of the ALDH2 Lys alleles with the ALDH2-alcohol drinking interaction. No significant association of ADH1B with gastric cancer was observed. CONCLUSION: The observed ALDH2-alcohol drinking interaction and the direct effect of ALDH2 Lys alleles may suggest the involvement of acetaldehyde in the development of gastric cancer.

Efficacy of the 6-mm fully covered self-expandable metal stent during endoscopic ultrasound-guided hepaticogastrostomy as a primary biliary drainage for the cases estimated difficult endoscopic retrograde cholangiopancreatography: A prospective clinical study.

BACKGROUND AND AIM: Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is performed as an alternative to the percutaneous or surgical approach. Despite high success rates, the adverse events rate is high. Recently, we used 6-mm fully covered self-expandable metal stents to prevent adverse events and allow easy re-intervention. The purposes were to evaluate the safety, feasibility, and clinical efficacy. METHODS: A prospective study to confirm the safety of EUS-HGS was carried out in six patients, followed by a trial to evaluate the feasibility and efficacy of EUS-HGS in approximately 12 additional patients. We permitted a total of 18 to 20 patients in consideration of possibility such as the deviation after providing informed consent. RESULTS: Twenty patients underwent EUS-HGS. No treatment-related adverse events described in the safety assessment criteria were seen. The technical and clinical success rates were 100% and 95%. The adverse event rate was 15%. Focal cholangitis was seen in two patients and fever in one patient. All cases were treated conservatively. Stent dysfunction was seen in 10 patients. The causes of stent dysfunction were biliary sludge (n = 6) and stent dislocation (n = 4). In nine cases, a new stent was easily inserted. Percutaneous drainage was selected in only one patient because of worsening general condition. CONCLUSIONS: The 6-mm fully covered self-expandable metal stent is safe and effective, especially for avoiding serious adverse events and allowing easy re-intervention. (UMIN000006785).

Incidence and treatment of metachronous gastric cancer after proximal gastrectomy.

BACKGROUND AND PURPOSE: Proximal gastrectomy (PG) is a widely accepted function-preserving surgical procedure; however, the incidence and treatment of metachronous gastric cancer (MGC) after PG have been the subject of a number of reports. METHODS: We collected data from 1576 consecutive patients who underwent gastrectomy for gastric cancer between January, 2003 and December, 2010, and analyzed the outcomes of 671 patients treated with PG or distal gastrectomy (DG) for cT1N0 disease. We also discuss the treatments for MGC. RESULTS: MGC was diagnosed within a median follow-up of 52.8 months after PG and DG in six (6.6%) and nine (1.8%) patients, respectively. The cumulative prevalence of MGC after PG was significantly higher than that after DG; P = 0.005. Univariate and multivariate analysis revealed male sex and PG as significant risk factors for MGC (P = 0.014 and P = 0.026, respectively). Five of the six patients who underwent PG were treated by endoscopic submucosal dissection. CONCLUSIONS: The incidence of MGC after PG was significantly higher than that after DG. However, most of the MGCs that developed after PG could be treated by endoscopic submucosal dissection.