1. Department of Surgery Kyoto University Graduate School of Medicine Kyoto Japan
2. Department of Surgery Osaka Red Cross Hospital Osaka Japan
3. Department of Surgical Oncology The University of Texas MD Anderson Cancer Center Houston TX USA
4. Department of Surgery Shimane Prefectural Central Hospital Shimane Japan
5. Department of Coloproctological Surgery Juntendo University Faculty of Medicine Tokyo Japan
6. Division of Surgery Gastrointestinal Center Yokohama Shin‐Midori General Hospital Yokohama Japan
7. Suda Medical Clinic Kawasaki Japan
8. Department of Surgery Kitasato University School of Medicine Kanagawa Japan