Inter-prefectural regional disparities in gastric cancer surgery: A Japanese nationwide population-based cohort study from 2014 to 2019

Aim This study aimed to investigate the regional disparities in gastric cancer surgery in Japan. Methods The annual incidence of gastric cancer and number of gastrectomies, board-certified surgeons in gastroenterology by the Japanese Society of Gastroenterological Surgery, and board-certified surgeons by the Japan Society for Endoscopic Surgery were evaluated by prefecture in Japan during 2014-2019. Medium-sized regional disparities were assessed using the Gini coefficient. Gastrectomies were further broken down by site (distal; proximal; total) and approach (open vs laparoscopic). Moreover, we compared the urban and rural regional disparities in all study variables. Results The annual national average incidence of gastric cancer was 127 466 and the number of gastrectomies was 49 128. Gini coefficients for almost all variables, except for board-certified surgeons by the Japan Society of Endoscopic Surgery, were <0.2, indicating low inequality. The incidence of gastric cancer, the number of gastrectomies, and the aging rate were significantly higher in rural prefectures than in urban prefectures. Conclusion Inter-prefectural regional disparities in gastric cancer surgery were generally small; however, both the incidence of gastric cancer and number of gastrectomies were higher in rural prefectures, where the aging rate was also increased. This study provides an overview of the landscape of gastric cancer care in Japan.