1. Gastroenterological Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
2. Department of Surgery and Science Faculty of Medicine, Academic Assembly, University of Toyama, Toyama, Japan
3. Department of Surgery, Kansai Medical University, Hirakata, Japan
4. Department of Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan
5. Department of Surgery, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
6. Department of Gastroenterological Surgery II, Faculty of Medicine, Hokkaido University, Sapporo, Japan
7. Department of Hepatobiliary–pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, Ehime, Fukuoka, Japan
8. Biostatistics Centre, Graduate School of Medicine, Kurume University, Fukuoka, Japan
9. Department of Gastrointestinal Surgery, Jichi Medical University, Tochigi, Japan
10. Department of Molecular-Targeting Cancer Prevention, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan