Prognostic nutritional index predicts the prognosis of patients with advanced esophageal cancer treated with immune checkpoint inhibitors: a retrospective cohort study - Wu, Mengjing; Zhu, Yunyun; Chen, Xiancheng; Wang, Xinpeng; Lin, Xinyue; Yan, Xue; Mo, Peng; Ye, Ying; Zeng, Yanjing; Yang, Yanyong; Fu, Zhichao (Journal of Gastrointestinal Oncology, 2023)