Analysis Of Efficacy And Curative Effect Predictors Of Sintilimab Combined With SOX Regimen In The First-Line Treatment Of HER-2 Negative Advanced Gastric Cancer Patients

BACKGROUND:Gastric cancer(GC)is a common malignant tumor of the gastrointestinal tract,and it is also a major problem plaguing the world.In 2020,the incidence and mortality of gastric cancer in my country will rank third among all kinds of malignant tumors.With the continuous development of society and changes in human eating habits,the incidence of gastric cancer is gradually increasing.However,since the early screening of gastric cancer has not yet been comprehensively and effectively popularized,most patients are already at an advanced stage when they seek medical treatment.Chemotherapy is one of the important methods for the treatment of gastric cancer.More options,but the prognosis is not ideal.In recent years,immunotherapy has been incorporated into the treatment of advanced gastric cancer,but the effect of single-drug immunotherapy is limited.The results of ORIENT-16 established the first-line use of sintilimab combined with oxaliplatin + capecitabine(XELOX)regimen in human epidermal growth factor receptor 2(HER-2)negative compared with the placebo control group,sintilimab combined with XELOX significantly prolongs the progression-free survival(PFS)and overall survival(OS)of patients.In clinical practice,we have observed that sintilimab combined with SOX regimen has a good curative effect,but there is no research on sintilimab combined with SOX regimen in the first-line treatment of HER-2negative advanced gastric cancer.OBJECTIVE:This study aims to analyze the clinical efficacy and safety of first-line sintilimab combined with SOX regimen in patients with HER-2 negative advanced gastric cancer,and to explore possible predictors of efficacy.METHODS:A total of 43 patients with HER-2 negative advanced gastric cancer who received sintilimab combined with SOX regimen as first-line treatment in Henan Provincial People’s Hospital from May 2019 to May 2022 were retrospectively analyzed.The basic characteristics,pathological data and peripheral blood data within 14 days before the start of treatment were collected.Imaging tests were performed every 2 treatment cycles,and the efficacy was evaluated using the Immunotherapy respond evaluation criteria in solid tumors(i RECIST)standard.Gender,age,Eastern cooperative oncology group performance status(ECOG PS)score before treatment,degree of tumor differentiation,programmed cell death-ligand 1(combined positive score)(PD-L1(CPS)),neutrophil-lymphocyte ratio(NLR),lactate dehydrogenase(LDH),platelet-lymphocyte ratio(PLR),prognostic nutritional index(PNI)predictive effect on curative effect.The main goal of the study is the objective response rate(ORR),and the secondary endpoints include PFS,OS,disease control rate(DCR)and treatment-related adverse events(TRAE).Kaplan-Meier survival analysis and COX regression analysis were used to analyze the predictive factors affecting the prognosis of gastric cancer,and the Log-rank test was used for significance analysis.RESULTS:43 patients with advanced gastric cancer received the first-line treatment of sintilimab combined with SOX regimen,of which 21 patients were evaluated as partial response(PR),15 patients were evaluated as stable disease(SD),and 7 patients were evaluated as it is progressive disease(PD).ORR and DCR were48.84%(21/43)and 83.72%(36/43).The median progression free survival(mPFS)of all patients was 8.6months(95% CI: 7.916-9.284),and the median overall survival(mOS)was 16.9 months(95% CI:14.078-19.722).Using the median as the best cut-off value,the cut-off values of age,NLR,PNI and PLR were 62.0,2.6,45.4 and 198.0.The analysis showed that tumor differentiation degree,PLR,ECOG PS score were significantly correlated with PFS(P< 0.05),PNI,PD-L1 expression,ECOG PS score were significantly correlated with OS(P < 0.05);the COX risk ratio was more Factor analysis showed that patients with high ECOG PS score had earlier disease progression,significantly shortened median PFS(HR:3.714,95%CI: 1.417-9.734,P=0.008),poor prognosis,and significantly shortened median OS(HR:10.111,95%CI: 2.022-50.559,P=0.005);low PLR(HR:2.395,95%CI: 1.065-5.383,P=0.035)was an independent factor for PFS prolongation,high PD-L1(CPS)(HR:0.121,95%CI: 0.025-0.591,P=0.009)is an independent factor of OS prolongation.Among the 43 patients,39 patients(90.70%)had grade 1-2adverse reactions,and 4 patients(9.30%)had grade 3 or higher adverse reactions,including fever,liver function injury,bone marrow suppression,anemia,safety consistent with previous literature.There were no treatment-related deaths in this study.CONCLUSION:In the first-line treatment of HER-2 negative advanced gastric cancer,sintilimab combined with SOX regimen has shown a good curative effect and survival advantages,and its safety is controllable.Multivariate analysis showed that PLR and ECOG PS were independent predictors of PFS(P<0.05),and PD-L1 and ECOG PS were independent predictors of OS(P<0.05).The conclusion of this study needs to be further confirmed by expanding the sample size.