Efficacy And Safety Analysis Of PD-1 Inhibitors Plus Chemotherapy In The Treatment Of Advanced Gastric Cancer

Objective:The purpose of this study was to investigate the efficacy and safety of PD-1inhibitors plus chemotherapy in patients with advanced gastric cancer,and to analyze the related factors affecting the prognosis.Methods:Clinical data of patients with advanced gastric cancer admitted to the Department of Gastrointestinal Surgery of the First Affiliated Hospital of Nanchang University from September 2020 to September 2022 were retrospectively collected.There is a combination chemotherapy group that receives PD-1 inhibitors plus chemotherapy,and chemotherapy alone group that receives chemotherapy without PD-1 inhibitors.Based on the imaging findings of the patients,RECIST 1.1 was used to evaluate the short-term efficacy of the two groups and a multidisciplinary discussion(MDT)was conducted to evaluate the feasibility of conversion surgery.Treatment-related adverse events were evaluated in both groups according to Common Adverse Event Evaluation Criteria(CTCAE)5.0 to evaluate their safety.Kaplan-Meier method was used to compare the difference of progression-free survival(PFS)and overall survival(OS)between the two groups after treatment.Univariate and multivariate Cox regression analysis was used to explore prognostic factors in the combination chemotherapy group.Results:According to the inclusion and exclusion criteria,a total of 95 eligible patients were included in this study,including 51 patients in the combination chemotherapy group and 44 patients in the chemotherapy alone group.There were no statistically significant differences(P > 0.05)in clinicopathologic data(age,sex,EOCG PS,Lauren’s classification,BMI,tumor location,peritoneal metastasis,ascites,signet ring cell carcinoma,number of distant metastatic organs,and chemotherapy regimen)between the two groups before treatment.After at least 4 cycles of treatment,disease progression(PD)was less than that in the chemotherapy alone group(13.7% vs.20.5%),but the difference was not statistically significant.Objective response rate(ORR)and disease control rate(DCR)in the combined chemotherapy group were better than those in the chemotherapy alone group.The objective response rate(ORR)was statistically different between the two groups(52.9% vs.31.8%,P=0.038),and combination chemotherapy group showed better short-term efficacy.The conversion operation rate of combination chemotherapy group was higher than that of chemotherapy alone group(17.6% vs.9.1%),but the difference was not statistically significant(P > 0.05).Treatment-related adverse reactions in the two groups were mainly adverse events in the blood and digestive system,and no serious immunerelated adverse events occurred.The total incidence of all kinds of adverse events in the combined chemotherapy group was generally higher than that in the chemotherapy alone group,but the differences were not statistically significant(P>0.05).Survival analysis showed that the median progression-free survival(mPFS)was 8.0 months and the median overall survival(mOS)was 14.0 months in the combined chemotherapy group,and the median progression-free survival(mPFS)was 6.3 months and the median overall survival(mOS)was 9.2 months in the chemotherapy alone group.The combination chemotherapy group obtained longer PFS and OS.Through univariate and multivariate Cox regression analysis,it was found that ascites and the number of organ metastasis were independent risk factors for PFS in the combination chemotherapy group,while the number of organ metastasis was independent risk factors for OS in the combination chemotherapy group.Conclusions:The short-term efficacy of PD-1 inhibitors plus chemotherapy in the treatment of advanced gastric cancer is better than that of chemotherapy alone,which can improve the ORR of advanced gastric cancer and has good short-term efficacy.Besides,PFS and OS are prolonged in patients,and the survival rate of patients is improved without significant adverse events.The safety is within a controllable range。PD-1 inhibitor plus chemotherapy may be one of the conversion therapy for advanced gastric cancer.Ascites and the number of metastatic organs are factors affecting PFS in patients with advanced gastric cancer treated with PD-1 inhibitor combined with chemotherapy.The number of metastatic organs is a factor affecting OS in patients with advanced gastric cancer treated with PD-1 inhibitor combined with chemotherapy.