Abstract: Objective The aim of this study was to explore the efficacy,safety difference and prognostic factors between first-line immune checkpoint inhibitor combined with standard chemotherapy and standard chemotherapy alone in patients with advanced esophageal squamous cell carcinoma(ESCC)in the real world.Methods The clinical data of 107 patients with locally advanced or metastatic ESCC who were treated in our hospital from January 2018 to December 2020 were retrospectively analyzed.According to their first-line treatment schemes,they were divided into the application of programmed cell death protein-1(PD-1)inhibitors combined standard chemotherapy group and the standard chemotherapy group alone.The progression free survival(PFS),Objective response rate(ORR),disease control rate(DCR)and the occurrence of treatment-related adverse events(TRAEs)were compared between of the two groups and influencing factors related to PFS in patients with advanced ESCC were analyzed.Results A total of 107 patients(56 in the combined treatment group and 51 in the chemotherapy group)were collected.After propensity score matching(PSM),31 patients in the combined treatment group and 31 patients in the chemotherapy group were obtained.There was no significant difference in ORR between the combined chemotherapy group and the chemotherapy alone group(38.7% vs. 19.4%,P＞0.05);the difference in DCR was not statistically significant(96.8% vs. 90.3%,P＞ 0.05);the difference in PFS was statistically significant(median PFS:11.87 months vs. 7.7 months,P=0.001).Cox regression analysis showed that use of PD-1 inhibitors and the location of lesions were independent influencing factors of PFS.The incidence of TRAEs in the combined chemotherapy group and chemotherapy alone group were 80.6% and 67.7%,respectively,and 5 cases(16.1%)in the combined chemotherapy group had immune-related adverse events(irAEs),and the above adverse reactions were tolerable or relieved after drug treatment,without affecting the use of chemotherapy drugs.Conclusion In the real world clinical practice,the efficacy of first-line immune checkpoint inhibitor combined with standard chemotherapy in patients with advanced ESCC is better than that of standard chemotherapy alone.No discontinuation due to immunotherapy-related adverse reactions was observed.The prognosis of patients with ESCC lesions located in the upper and middle segments is better than that of patients with ESCC lesions located in the lower segment.

Key words: Advanced esophageal squamous cell carcinoma, Immune checkpoint inhibitor, Chemotherapy, Efficacy, Predictive factors