Comparative efficacy and safety of immunotherapy for patients with advanced or metastatic esophageal squamous cell carcinoma: a systematic review and network Meta-analysis. - Gao, Tian-Tian; Shan, Jia-Hui; Yang, Yu-Xian; Zhang, Ze-Wei; Liu, Shi-Liang; Xi, Mian; Liu, Meng-Zhong; Zhao, Lei (BMC Cancer, 2022)