Background: Gastric cancer is one of the most common types of cancers and incidence is high in East Asia. Resection of gastric malignant tumor includes several choices from endoscopic resection of early-stage cancer to open surgery of total gastrectomy. However, nationwide data of gastric resection has been lacking. Methods: This is observational study using open data from the National Database of Health Insurance Claims, which covered most claims data from national health insurance. We described the secular trend of each type of resection for gastric malignant tumor, age and sex distribution, and regional disparity for the period of 2014-2021. Results: The annual number of resections was highest (109 thousand) in 2015 and dropped to 90 thousand in 2020 after the Coronavirus disease 2019 pandemic. The proportion of endoscopic resection has been increasing from 47% in 2014 to 57% in 2021. The proportion of total gastrectomy has been decreasing from 17% in 2014 to 10% in 2021. Male patients accounted for 70% of resection in 2021. Patients aged ≥ 65 years accounted for 83.8% of all types of gastric resection and 87.1% of ESD (Endoscopic Submucosal Dissection), respectively. The annual incidence of gastric resection per million general population was highest in Tottori (1,236) and lowest in Okinawa (251). The proportion of endoscopic resection was highest in Miyagi (66%) and lowest in Aichi (45%). The proportion of open surgery was highest in Aomori (36%), and lowest in Wakayama (5%). Conclusions: ESD and robotic surgery has been increasing and open and total gastrectomy has been decreasing. There are large regional disparities in the choice of resection. Standardization of screening and treatment, and even distribution of specialists are crucial.

The authors have declared no competing interest.

This work was supported by the NCGM Intramural Research Fund 24A005

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