1. Department of Colorectal Surgery National Cancer Center Hospital East Kashiwa Japan
2. Colorectal and Pelvic Surgery Division Shinko Hospital Kobe Japan
3. Department of Colorectal Surgery National Cancer Center Hospital Chou‐ku Japan
4. Department of Surgery Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital Bunkyo‐ku Japan
5. Department of Surgery Iwate Medical University School of Medicine Morioka Japan
6. Department of Surgery Kitasato University School of Medicine Sagamihara Japan
7. Division of Colon and Rectal Surgery Shizuoka Cancer Center Sunto‐gun Japan
8. Clinical Research Support Office National Cancer Center Hospital East Kashiwa Japan