1. Department of Gastroenterological Surgery, Gastroenterological Center, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
2. Department of Upper-gastrointestinal Surgery, Kitasato University School of Medicine, Kanagawa, Japan
3. Department of Gastroenterology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
4. Division of Gastroenterology, Endoscopy Center, Showa University Fujigaoka Hospital, Yokohama, Japan