1. Department of Radiation Oncology, National Cancer Center and Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
2. Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
3. Department of Radiation Oncology, Shenzhen Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China