1. Department of Surgical Oncology, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
2. Department of Surgery, Toyama City Hospital, Toyama, Toyama 939‑8511, Japan
3. Department of Mathematics, Division of General Education, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
4. Department of Gastrointestinal Surgery, Kanazawa University, Kanazawa, Ishikawa 920‑8641, Japan