1. Division of Lower Gastrointestinal, Department of Gastroenterological Surgery, Hyogo Medical University , Nishinomiya , Japan
2. Department of Biostatistics, Hyogo Medical University , Nishinomiya , Japan
3. Department of Clinical Epidemiology, Hyogo Medical University , Nishinomiya , Japan
4. Department of Gastrointestinal Surgery, Ghent University Hospital, and Cancer Research Institute Ghent (CRIG), Ghent University , Ghent , Belgium
5. Department of Colorectal Surgery, National Cancer Centre Hospital , Tokyo , Japan
6. Division of Molecular and Diagnostic Pathology, Niigata University, Graduate School of Medical and Dental Sciences , Niigata , Japan
7. Department of Gastroenterological Surgery, Yokohama City University, Graduate School of Medicine , Yokohama , Japan
8. Department of Surgery, Hepato-Biliary-Pancreatic Surgery Division, Graduate School of Medicine, University of Tokyo , Tokyo , Japan
9. Department of Surgery, Tokyo Metropolitan Ohkubo Hospital , Tokyo , Japan