Department of Surgery, School of Medicine, Yokohama City University, 3-9, Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan. rino@yokohama-cu.ac.jp. Department of Surgery, School of Medicine, Yokohama City University, 3-9, Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan. Department of Gastrointestinal Surgery, Kanagawa Cancer Center, 3-2, Nakao, Asahi-ku, Yokohama, 241-8515, Japan.