1. Department of Gastroenterological, Breast and Endocrine Surgery Yamaguchi University Graduate School of Medicine Yamaguchi Japan
2. Kansai Hepato‐Biliary Oncology Group Osaka Japan
3. Department of Gastroenterological Surgery Graduate School of Medicine, Osaka University Osaka Japan
4. Department of Surgery Osaka International Cancer Institute Osaka Japan
5. Department of Surgery Graduate School of Medicine, Kyoto University Kyoto Japan
6. Division of Hepato‐Biliary‐Pancreatic Surgery, Department of Surgery Graduate School of Medicine, Kobe University Kobe Japan
7. Department of Clinical Oncology Kagawa University Hospital Kagawa Japan
8. Department of Gastroenterological Surgery Hyogo College of Medicine Nishinomiya Japan
9. Department of Surgery Kansai Rosai Hospital Amagasaki Japan
10. Department of Surgery Osaka National Hospital Osaka Japan
11. Department of Surgery Higashiosaka City Medical Center Osaka Japan
12. Medical Center for Clinical and Translational Research Hiroshima University Hospital Hiroshima Japan
13. Department of Oncology Center Yamaguchi University Hospital Yamaguchi Japan