OBJECTIVE: To systematically evaluate the efficacy of programmed death-1/programmed death ligand-1（ PD-1/PD-L1） monoclonal antibody in gastric cancer or adenocarcinoma of the gastroesophageal junction.METHODS: PubMed

Embase

the Cochrane Library database and abstracts of American society of clinical oncology（ ASCO） conferences in the past three years

and European society for medical oncology（ ESMO） conferences in 2020 were retrieved to collect the prospective studies

phase Ⅱ and phase Ⅲ clinical trials( the study group was treated with PD-1/PD-L1 monoclonal antibody alone or in combination with chemotherapy

while the control group received chemotherapy or placebo. The retrieval deadline was Sept. 26 th

2020. The efficacy of different treatment regimens（ PD-1/PD-L1 monoclonal antibody treatment group compared with chemotherapy group

PD-1/PD-L1 monoclonal antibody treatment + chemotherapy group compared with chemotherapy group

and PD-1/PD-L1 monoclonal antibody treatment group compared with placebo group） was assessed by subgroup analysis

and forest plotting was performed by Stata SE 12 software. RESULTS: Seven clinical trials were ultimately enrolled

including three original papers

two abstracts of ASCO conferences and two abstracts of ESMO conferences.（ 1） The differences in overall survival（ OS）（ HR = 0. 96

95% CI = 0. 87-1. 07

P = 0. 451） and objective response rate（ ORR）（ RR = 0. 65

95% CI = 0. 39-1. 09

P = 0. 102） between the PD-1/PD-L1 monoclonal antibody treatment group alone and the chemotherapy group were not statistically significant

yet the difference in progression free survival（ PFS） between two groups was statistically significant（ HR = 1. 45

95% CI = 1. 17-1. 81

P = 0. 001）.（ 2） The differences of OS（ HR = 0. 84

95% CI = 0. 76-0. 94

P = 0. 001）

PFS（ HR = 0. 78

95% CI = 0. 70-0. 86

P = 0. 000） and ORR（ RR = 1. 24

95% CI = 1. 10-1. 39

P = 0. 000） between the PD-1/PD-L1 monoclonal antibody treatment + chemotherapy group and the chemotherapy group were statistically significant.（ 3） The differences of OS（ HR = 0. 63

95% CI = 0. 51-0. 78

P = 0. 000）

PFS（ HR = 0. 60

95% CI = 0. 49-0. 75

P = 0. 000） and ORR（ RR = 29. 93

95% CI = 1. 84-485. 72

P = 0. 017）between the PD-1/PD-L1 monoclonal antibody treatment group and the placebo group were statistically significant.CONCLUSIONS: The results of this study suggest that PD-1/PD-L1 monoclonal antibody combined with chemotherapy may benefit patients with advanced gastric cancer or adenocarcinoma of the gastroesophageal junction.Compared with placebo

PD-1/PD-L1 monoclonal antibody alone also benefits patients with advanced gastric cancer or adenocarcinoma of the gastroesophageal junction. However

compared with chemotherapy

patients with advanced gastric cancer or adenocarcinoma of the gastroesophageal junction may not get a more significant treatment effect from PD-1/PD-L1 monoclonal antibody

and more evidence is needed to confirm these findings.