1 Department of Gastrointestinal Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan; Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Gastrointestinal Surgery, Peking University Cancer Hospital and Institute, Hai-Dian District, Beijing 100142, China.
2 Division for Health Service Promotion, University of Tokyo, Tokyo, Japan.
3 Department of Gastrointestinal Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
4 Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Gastrointestinal Surgery, Peking University Cancer Hospital and Institute, Hai-Dian District, Beijing 100142, China. Electronic address: jijiafu@hsc.pku.edu.cn.