1. Department of Minimally Invasive Surgical and Medical Oncology, Fukushima Medical University, Fukushima, Japan
2. Department of Biostatistics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
3. Department of Gastroenterological Surgery, Gastroenterological Center, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
4. Cancer Treatment Center, Kochi Medical School Hospital, Kochi University, Nankoku, Japan
5. Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Nagoya, Japan
6. Department of Surgery, Keio University, Tokyo, Japan
7. Department of Surgery, Yokohama City University, Yokohama, Japan
8. Faculty of Engineering, Tokyo University of Science, Tokyo, Japan
9. Department of Surgery, Tokai University, Isehara, Japan
10. Tokai Central Hospital, Kakamigahara, Japan
11. Japanese Foundation for Multidisciplinary Treatment of Cancer, Tokyo, Japan
12. Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama, Japan