1. Department of General Surgery, Graduate School of Medicine; Chiba University; 1-8-1 Inohana, Chuo-ku Chiba 260-8670 Japan
2. Toyota Regional Medical Center; Toyota Japan
3. Division of Surgical Oncology, Department of Surgery; Nagoya University Graduate School of Medicine; Nagoya Japan
4. Department of Surgery; Teikyo University School of Medicine; Tokyo Japan