1. Shonan Kamakura General Hospital, Kamakura, Tokyo, Japan
2. Japan Clinical Oncology Group Data Centre/National Cancer Centre, Tokyo, Japan
3. Saitama Cancer Centre, Saitama, Japan
4. Yamagata Prefectural Central Hospital, Yamagata, Japan
5. Niigata Cancer Centre Hospital, Niigata, Japan
6. Hyogo College of Medicine, Nishinomiya, Japan