Study On The Tumor Volume Changes And Clinical Significance Of Chemotherapy Combined With Bevacizumab In The Treatment Of Advanced Lung Adenocarcinoma

Objective:In this study,we analyzed the changes of tumor volume in patients with advanced lung adenocarcinoma before and after chemotherapy combined with bevacizumab,to explore the changes of tumor volume after chemotherapy combined with bevacizumab,and whether tumor regression rate has an impact on progression free survival.Methods:From January 2016 to December 2019,37 patients with advanced lung adenocarcinoma were collected from the Department of oncology,Shengjing Hospital Affiliated to China Medical University.All patients were diagnosed as lung adenocarcinoma by pathology or histology,and stage III and IV patients were inoperable.Among them,19 patients received pemetrexed+platinum combined with bevacizumab,15 patients received paclitaxel+platinum combined with bevacizumab,1 patient received gemcitabine+platinum combined with bevacizumab,and 2 patients received docetaxel+platinum combined with bevacizumab.Because the distribution of tumor volume size is non normal distribution,the Wilcoxon signed rank sum test of paired samples was conducted for the absolute volume and relative volume of tumor in each review cycle to explore the change rule of tumor volume size after chemotherapy combined with bevacizumab.The tumor volume regression rate after chemotherapy combined with bevacizumab was set as TSR=(V0-Vx)/V0×100%。RECIST 1.1 was used to evaluate the efficacy and calculate the progression free survival(PFS)of patients with advanced lung adenocarcinoma.Kaplan Meier method was used for survival analysis,log rank test for survival difference and Cox proportional hazards model for multivariate analysis.Results:Paired analysis showed that the absolute tumor volume before chemotherapy combined with bevacizumab was V0(mm~3).After2 cycles of chemotherapy combined with bevacizumab,the absolute volume of tumor V1(mm~3)The absolute volume(Z=-4.893,P<0.01)and relative volume(Z=-5.183,P<0.01)of tumor in two months were significantly different.The median PFS was 7.8 months.The tumor regression rate in the second cycle after chemotherapy combined with bevacizumab was TSR,TSR=(V0-V1)/V0×100%.The critical value of TSR was 30%.Kaplan Meier analysis showed that histological differentiation(P=0.015),tumor regression rate(P=0.037),chemotherapy regimen(P=0.004)and tumor volume before treatment(P=0.0034)were the influencing factors of PFS(P<0.05).Patients with significant tumor regression,small tumor volume before treatment and high degree of tissue differentiation had longer PFS There was significant difference in PFS between subgroups of histological differentiation(P<0.05),but no significant difference in PFS between subgroups of tumor size before treatment(P>0.05).Conclusion:After chemotherapy combined with bevacizumab,the tumor retreated obviously in the first 2 cycles,the volume decreased gradually from the 2nd cycle to the 6th cycle,and the tumor volume tended to increase after the 6th cycle.The relative volume of tumor increased significantly after 4 cycles of maintenance therapy to 6cycles of maintenance therapy.In the first 2 cycles,the patients with obvious tumor volume retraction and higher tumor histological differentiation had longer progression-free survival.The early tumor withdrawal rate was a prognostic factor affecting the progression-free survival and could be used as an independent predictor of PFS.