1. Department of Head and Neck Medical Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
2. Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
3. Department of Medical Oncology and Hematology, Cancer Center, Kobe University Hospital, Kobe, Hyogo, Japan
4. Department of Head and Neck Surgery, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan
5. Department of Head and Neck Surgery, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
6. Department of Head and Neck Surgery, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
7. Department of Otorhinolaryngology, Head and Neck Surgery, Gifu University Hospital, Gifu, Gifu, Japan
8. Department of Otolaryngology and Head and Neck Surgery, University of Tokyo, Bunkyo, Tokyo, Japan
9. Department of Otorhinolaryngology, Head and Neck Surgery, School of Medicine, Yokohama City University, Yokohama, Kanagawa, Japan
10. Department of Radiation Oncology, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan
11. Department of Radiation Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
12. Department of Radiation Oncology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
13. Department of Medical Oncology, Cancer Institute Hospital, Koto, Tokyo, Japan
14. Department of Medical Oncology, Kindai University Faculty of Medicine, Sayama, Osaka, Japan
15. Department of Medical Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan
16. Division of Gastrointestinal Oncology, Shizuoka Cancer Center, Sunto, Shizuoka, Japan