Clinical Efficacy And Safety Analysis Of Receiving PD-1 Inhibitor-containing Regimen In Elderly Patients With Advanced Gastric Cancer

Background and Objective:The first-line chemotherapy regimens for patients with advanced gastric cancer have been continuously optimized,but the survival of the patients remains unsatisfactory.In recent years,programmed cell death protein-1(PD-1)inhibitors have emerged as a novel therapy option for advanced gastric cancer.Since the aging population in China is a serious concern,and reports of PD-1 inhibitor-containing regimens for the treatment of elderly patients with advanced gastric cancer are rare,this study aims to evaluate the clinical efficacy and safety of PD-1inhibitor-containing regimens in the treatment of elderly patients with advanced gastric cancer.Methods:The study included elderly advanced gastric patients aged ≥ 65 years old who received PD-1 inhibitor-containing therapy in the First Affiliated Hospital of Nanchang University from January 2018 to May 2021.Frequency and proportion were used to summarize the category data.The objective response rate(ORR)and disease control rate(DCR)were compared by Chi-square test or Fisher’s exact probability.Multivariate analysis of the curative effect was evaluated by logistic regression analysis.The Cox regression model was applied to find independent indicators related to progression-free survival(PFS)and overall survival(OS).The multivariate analysis includes factors that were statistically significant in the univariate analysis.The PFS and OS curves were calculated by the Kaplan-Meier method,and the difference was assessed by the log-rank test.SPSS 25.0 statistical software was used for all the statistical analyses,and differences were considered statistically significant at P<0.05.Results:A total of 51 patients were included in this study according to the inclusion and exclusion criteria.The median age of the 51 patients in this study was 69 years old(65-86 years old).A total of 21 patients received PD-1 inhibitor-containing first-line therapy regimens,of which only 1 patient received PD-1 inhibitor therapy alone and20 patients received PD-1 inhibitors combined with chemotherapy or targeted therapy.The combined chemotherapy regimens mainly included the XELOX regimen(oxaliplatin + capecitabine),the FOLFOX regimen(oxaliplatin + fluorouracil +levofolinate calcium),the SOX regimen(oxaliplatin + S-1),and paclitaxel drugs +fluorouracil;the combined targeted therapy drug was apatinib mesylate.There were30 patients who received second-line and later-line therapy,of which 3 patients received PD-1 inhibitor therapy alone,and 27 patients received combination therapy.The combined chemotherapy regimens were mainly paclitaxel + fluorouracil,irinotecan + fluorouracil,and SOX regimen;the combined targeted therapy drugs were apatinib mesylate and trastuzumab.The results of this study showed that the overall ORR and DCR of 51 patients were 31.4% and 78.4%,respectively.ORR was higher in patients treated with PD-1 inhibitor-containing regimens in first-line compared to second and later line therapy(52.4% vs 16.7%,p<0.05).In the univariate analysis of PFS,2 or more distant metastatic organs,the high lactate dehydrogenase(LDH),and the non-excellent lung immune prognostic index(LIPI)scores group were all associated with low PFS(3.5m vs 12 m,HR,3.745;95%CI: 1.667-7.244;p<0.05),(4m vs 12 m,HR,2.304;95%CI: 1.137-4.670;p<0.05),(4m vs 12 m,HR,2.822;95%CI: 1.314-6.059;P<0.01);and the number of distant metastatic organs was an independent prognostic risk factor for PFS.Univariate analysis of OS showed that second-line and later-line treatment(12m vs 18 m,HR,2.397;95%CI: 1.006-5.713;p<0.05),2 or more distant metastases(12.3m vs 19 m,HR,3.024;95%CI: 1.191-7.677;p < 0.05),high LDH(5.1m vs 18 m,HR,3.050;95%CI: 1.302-7.147;p < 0.05),non-excellent LIPI scores(7m vs 19 m,HR,2.607;95% CI: 1.060-6.407;p < 0.05)were all associated with low OS.Immune-related adverse events occurred in only15.7% of all patients,and there was no grade 3 or higher immune-related adverse events.Conclusion:PD-1 inhibitor-containing regimens are safe and effective in elderly patients with advanced gastric cancer.The use of PD-1 inhibitor-containing regimens for first-line therapy may result in a greater survival benefit for elderly patients with advanced gastric cancer than later-line therapy.