1. Department of Gastroenterological Surgery and Clinical Oncology , Graduate School of Medicine, Toho University, Tokyo 142-8541 , Japan
2. Department of Gastroenterological Surgery , Gastroenterology Center, The Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo 135-8550 , Japan
3. Department of Gastroenterological Surgery , Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8555 , Japan
4. Department of Digestive Surgery , Tohoku University Graduate School of Medicine, Miyagi 980-8574 , Japan
5. Department of Frontier Surgery , Graduate School of Medicine, Chiba University, Chiba 263-8522 , Japan
6. Department of Gastroenterological Surgery , Toranomon Hospital and Okinaka Memorial Institute for Medical Research, Tokyo 105-8470 , Japan
7. Department of Gastrointestinal Surgery , Tokyo Medical and Dental University, Tokyo 113-8519 , Japan
8. Department of Gastrointestinal Surgery , Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655 , Japan
9. Department of Gastroenterological Surgery , Saitama Cancer Center Hospital, Saitama 362-0806 , Japan
10. Department of Gastroenterological Surgery , Nagoya City University Graduate School of Medical Sciences, Aichi 467-8601 , Japan
11. Division of Gastroenterological Surgery , Chiba Cancer Center, Chiba 260-8717 , Japan
12. Department of Surgery , Gastroenterological Center, Yokohama City University, Kanagawa 236-0004 , Japan
13. Department of Surgery , Institute of Gastroenterology, Tokyo Women's Medical University, Tokyo 162-8666 , Japan
14. Division of Esophageal Surgery , Shizuoka Cancer Center, Shizuoka 411-8777 , Japan
15. Department of Surgery , National Center for Global Health and Medicine, Tokyo 162-8655 , Japan