1. JCOG Data Center/Operations Office, National Cancer Center Hospital, Tokyo, Japan
2. Department of Surgical Oncology, Hiroshima University Hospital, Hiroshima, Japan
3. Division of Thoracic Surgery, National Cancer Center Hospital East, Chiba, Japan
4. Department of Thoracic Surgery, Aichi Cancer Center Hospital, Nagoya, Japan
5. Department of Chest Surgery, St. Marianna University School of Medicine, Kanagawa, Japan
6. Division of Thoracic Surgery, National Cancer Center Hospital, Tokyo, Japan