1. Department of Hepatobiliary–Pancreatic and Gastrointestinal Surgery, International University of Health and Welfare School of Medicine, Chiba
2. Department of Clinical Epidemiology and Health Economics, School of Public Health
3. Department of Cardiovascular Medicine, The University of Tokyo, Bunkyo-ku
4. Department of Surgery, Keio University School of Medicine, Shinjyuku-ku
5. Department of Health Policy and Informatics, Tokyo Medical and Dental University Graduate School, Bunkyo-ku
6. Division of Esophageal Surgery, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan