1. Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center Hospital, Tokyo 104-0045, Japan
2. Cancer Medicine, Jikei University Graduate School of Medicine, Tokyo 105-0003, Japan
3. Endoscopy Division, National Cancer Center Hospital, Tokyo 104-0045, Japan
4. Department of Thoracic Oncology, National Cancer Center Hospital, Tokyo 104-0045, Japan