Clinical epidemiology of the endoscopic, laparoscopic, and surgical resection of malignant gastric tumors in Japan, 2014-2021: a retrospective study using open data from a national claims database

Background Gastric cancer is one of the most common malignancies and its incidence is high in East Asia. Several options are available for resection of malignant gastric tumors, ranging from endoscopic resection of early-stage cancer to open total gastrectomy. However, there has been a lack of nationwide data on gastric resection in Japan. Methods This observational study analyzed data from the publicly accessible National Database of Health Insurance Claims and Specific Health Checkups, which includes most national health insurance claims data in Japan. Trends in the various types of resection performed for malignant gastric tumors between 2014 and 2021, the age and sex distributions of patients undergoing these procedures, and regional disparities were investigated. Results The annual number of resections was highest in 2015 (109,000) and lowest in 2020 (90,000) after the COVID-19 pandemic. The proportion of endoscopic resections increased from 47% in 2014 to 57% in 2021 while the proportion of total gastrectomies performed during this period decreased from 17% to 10%. In 2021, 70% of patients who underwent resection were men. That year, 83.8% of all patients who underwent any type of gastric resection and 87.1% of those who underwent endoscopic submucosal dissection (ESD) were aged ≥65 years. The annual incidence of gastric resection per million general population was highest in Tottori (n=1,236) and lowest in Okinawa (n=251). The proportion of endoscopic resections was highest in Miyagi (66%) and lowest in Aichi (45%) and that of open surgery was highest in Aomori (36%) and lowest in Wakayama (5%). Conclusions Gastric malignancy is increasingly treated by endoscopic submucosal dissection rather than by open total gastrectomy. However, there are regional disparities in the resection methods used. Standardization of screening and treatment and a more even distribution of specialists are needed. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the NCGM Intramural Research Fund 24A005 ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study used (or will use) ONLY openly available human data that were originally located at　https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000177182.html I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors * NDB : National Database of Health Insurance Claims and Specific Health Checkups FY : fiscal year EMR : endoscopic mucosal resection ESD : endoscopic submucosal dissection LECS : laparoscopic and endoscopic collaborative surgery JED : Japan Endoscopy Database GIST : gastrointestinal stromal tumor NCD : National Clinical Database