1. Department of Surgery Kansai Medical University Osaka Japan
2. Department of Mathematics and Statistics in Medical Sciences Kyoto Prefectural University of Medicine Kyoto Japan
3. Biostatistics Division Clinical Research Support Center Central Coordinating Unit The University of Tokyo Tokyo Japan
4. Department of Surgery Graduate School of Medicine Hepato‐Biliary‐Pancreatic Surgery Division The University of Tokyo Tokyo Japan
5. Department of Gastroenterology Musashino Red Cross Hospital Tokyo Japan
6. Department of Diagnostic and Interventional Radiology Kobe University Graduate School of Medicine Kobe Japan
7. Department of Gastroenterology and Hepatology Kindai University Faculty of Medicine Osaka Japan
8. Department of Gastroenterology Juntendo University School of Medicine Tokyo Japan
9. Department of Pathology Keio University School of Medicine Tokyo Japan
10. Department of Clinical Laboratory Medicine Kurume University Hospital Kurume Japan
11. Department of Biostatics School of Public Health University of Tokyo Tokyo Japan
12. Department of Surgery Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
13. Advanced Preventive Medical Research Center Kanazawa University Kanazawa Japan
14. Department of Digestive Surgery Nihon University School of Medicine Tokyo Japan
15. National Center for Global Health and Medicine Tokyo Japan
16. Department of Hepato‐Biliary‐Pancreatic Surgery Osaka City University Graduate School of Medicine Osaka Japan