1. Department of Surgery Faculty of Medicine Kindai University Osaka‐Sayama Japan
2. Department of Surgery National Hospital Organization Osaka National Hospital Osaka Japan
3. Department of Surgery Osaka Police Hospital Osaka Japan
4. Department of Surgery Kansai Medical University Hirakata Japan
5. Department of Gastroenterological Surgery Higashiosaka City Medical Center Higashiosaka Japan
6. Department of Surgery Ikeda City Hospital Ikeda Japan
7. Department of Surgery Yao Municipal Hospital Yao Japan
8. Department of Surgery Kaizuka City Hospital Kaizuka Japan
9. Department of Surgery Toyonaka Municipal Hospital Toyonaka Japan
10. Department of Surgery Osaka Rosai Hospital Sakai Japan
11. Division of Surgical Oncology Department of Surgery Faculty of Medicine Tottori University Tottori Japan
12. Department of Digestive Surgery Nippon Medical School Tokyo Japan
13. Clinical Study Support Center Wakayama Medical University Wakayama Japan