1. State Key Laboratory of Oncology in South China; Department of Radiation Oncology; Sun Yat-sen University Cancer Center; Guangzhou People's Republic of China
2. Department of Radiation Oncology; Cancer Center, The First People's Hospital of Foshan; Foshan People's Republic of China
3. Department of Radiation Oncology; Fujian Provincial Tumor Hospital; Fuzhou People's Republic of China
4. Clinical Trials Center; Sun Yat-sen University Cancer Center; Guangzhou People's Republic of China
5. Department of Medical Statistics and Epidemiology; School of Public Health, Sun Yat-sen University; Guangzhou People's Republic of China