Inter-prefectural and urban-rural regional disparities in rectal cancer and rectal resections: A Japanese nationwide population-based cohort study from 2014 to 2019.

Aim: This observational study aimed to elucidate the regional disparities in rectal cancer (RC) and rectal resections (RRs) across Japan. Methods: The annual incidence of RC, and number of all RRs and board-certified surgeons by the Japan Society for Endoscopic Surgery were examined by prefecture in Japan from 2014 to 2019. The surgical approaches were broken down by open and laparoscopic. Disparities in 47 prefectures and urban-rural disparities were evaluated using the Gini coefficient and unpaired Results: The annual national average incidence of RC was 50 127 and the number of all RRs was 39 903. Gini coefficients for RC, and laparoscopic and all RRs were <0.2, indicating low inequality. There was no significant difference between urban and rural prefectures in the number of RRs, despite a significantly higher incidence of RC in rural prefectures and a significantly higher number of board-certified surgeons in urban prefectures ( Conclusion: RC and laparoscopic and all RRs exhibited minimal inter-prefectural disparities. The urban-rural analysis revealed significant differences in the incidence/number of RC and board-certified surgeons between urban and rural prefectures, despite minor differences in RRs regardless of approach. This pattern suggests a potential migration of surgical services from rural to urban areas. This preliminary study is expected to contribute to a basic epidemiological database for RC and RRs.