1. State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center , Guangzhou, P. R. China
2. Department of Radiation Oncology, Sun Yat-sen University Cancer Center , Guangzhou, P. R. China
3. School of Public Health, Sun Yat-sen University , Guangzhou, P. R. China
4. Department of Nasopharyngeal Carcinoma, Sun Yat-sen University Cancer Center , Guangzhou, P. R. China
5. Department of Cancer Prevention, Sun Yat-sen University Cancer Center , Guangzhou, P. R. China
6. Department of Clinical Oncology, University of Hong Kong, Hong Kong (Special Administrative Region) , People’s Republic of China
7. Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine , Nashville, TN, USA