1) Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
2) Department of General Surgical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
3) Department of Surgery, Surgical Oncology and Science, Sapporo Medical University, Sapporo, Japan
4) Department of Surgery, National Hospital Organization Osaka National Hospital, Osaka, Japan
5) Department of Gastroenterolgy and Gastrointestinal Oncology, National Cancer Center Hospital East, Kashiwa, Japan
6) Shizuoka Cancer Center Hospital and Research Institute, Sunto, Japan
7) Department of Biostatistics, Yokohama City University. School of Medicine, Yokohama, Japan
8) Department of Gastroenterological Surgery, Faculty of life Sciences, Kumamoto University, Kumamoto, Japan

Eiji Oki¹⁾, Hiroshi Saeki²⁾, Ichiro Takemasa³⁾, Takeshi Kato⁴⁾, Hiroya Taniguchi⁵⁾, Kentaro Yamazaki⁶⁾, Takeharu Yamanaka⁷⁾, Takayuki Yoshino⁵⁾, Hideo Baba⁸⁾, Masaki Mori¹⁾