Affiliation: | 1. Department of Cancer Epidemiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China;2. Department of Endoscopy, Linzhou Cancer Hospital, Henan 456550, China;3. Department of Epidemiology, Cixian Cancer Hospital, Heibei 056500, China;4. Department of Cancer Center, Feicheng People Hospital, Shandong 271600, China;5. Medical Record Room, Xuanwu Hosital, Beijing 100053, China |