Study of Pembrolizumab (MK-3475) Versus Investigator's Choice of Chemotherapy for Participants With Advanced Esophageal/Esophagogastric Junction Carcinoma That Progressed After First-Line Therapy (MK-3475-181/KEYNOTE-181)-China Extension Study

Beijing Cancer Hospital ( Site 0700), Beijing

Chinese PLA General Hospital (Site 0703), Beijing

Peking Union Medical College Hospital ( Site 0712), Beijing

Jilin Cancer Hospital ( Site 0718), Changchun

The First Hospital Of Jilin University ( Site 0719), Changchun

Harbin Medical University Cancer Hospital ( Site 0714), Harbin

Ruijin Hospital, Shanghai Jiaotong University ( Site 0701), Shanghai

Shanghai Chest Hospital ( Site 0727), Shanghai

Fudan University Shanghai Cancer Center ( Site 0723), Shanghai

Zhongshan Hospital affiliated to Fudan University ( Site 0715), Shanghai

Jiangsu Cancer Hospital (Site 0704), Nanjing

PLA Cancer Centre of Nanjing Bayi Hospital ( Site 0706), Nanjing

Anhui Provincial Hospital ( Site 0708), Hefei

The First Affiliated Hospital of Anhui Medical University ( Site 0707), Hefei

The Affiliated Hospital of Qingdao University ( Site 0709), Qingdao

The Second Affiliated Hospital of Zhejiang University School of Medicine ( Site 0705), Hangzhou

Sir Sun Sun Shaw Hosp, Zhejiang Univ,Oncology dept. ( Site 0720), Hangzhou

Zhejiang Cancer Hospital ( Site 0726), Hangzhou

Fujian Medical University Union Hospital ( Site 0721), Fuzhou

Fujian Province Cancer Hospital ( ( Site 0717), Fuzhou

Hunan Cancer Hospital ( Site 0722), Changsha

Wuhan Tongji Hospital ( Site 0724), Wuhan

Henan Cancer Hospital ( Site 0725), Zhengzhou