[1] Capital Med Univ, Dept Epidemiol & Hlth Stat, Sch Publ Hlth, Beijing Municipal Key Lab Clin Epidemiol, Beijing 100069, Peoples R China
[2] Chinese Acad Med Sci & Peking Union Med Coll, Dept Endoscopy, Natl Canc Ctr, Natl Clin Res Ctr Canc,Canc Hosp, Beijing 100021, Peoples R China
[3] Shandong First Med Univ & Shandong Acad Med Sci, Shandong Canc Hosp & Inst, Tai An 250000, Shandong, Peoples R China
[4] Gansu Prov Canc Hosp, Lanzhou 730000, Gansu, Peoples R China
[5] Zhengzhou Univ, Dept Canc Epidemiol & Prevent, Affiliated Canc Hosp, Henan Canc Hosp, Zhengzhou 450008, Henan, Peoples R China
[6] Shanxi Canc Hosp, Dept Epidemiol, Taiyuan 030013, Shanxi, Peoples R China
[7] Hebei Med Univ, Fourth Hosp, Shijiazhuang 050000, Hebei, Peoples R China
[8] Feicheng Peoples Hosp, Feicheng 271600, Shandong, Peoples R China
[9] Dongping Peoples Hosp, Tai An 271500, Shandong, Peoples R China
[10] Hebi Peoples Hosp, Dept Epidemiol, Hebi 458030, Henan, Peoples R China
[11] Yangcheng Canc Hosp, Yangcheng 048100, Shanxi, Peoples R China
[12] First Peoples Hosp Ningyang Cty, Jining 271400, Shandong, Peoples R China
[13] Cixian Inst Canc Prevent & Control, Cixian 056500, Hebei, Peoples R China
[14] Gansu Wuwei Canc Hosp, Wuwei 733000, Gansu, Peoples R China
[15] Minqin Cty Peoples Hosp, Minqin 733000, Gansu, Peoples R China
[16] Linze Cty Peoples Hosp, Linze 734200, Gansu, Peoples R China
[17] Shandan Cty Peoples Hosp, Shandan 734000, Gansu, Peoples R China
[18] Gaotai Cty Peoples Hosp, Zhangye 734300, Gansu, Peoples R China
[19] Chinese Acad Med Sci, Dept Gastroenterol, Peking Union Med Coll Hosp, Beijing 100730, Peoples R China