Prognostic Analysis Of Stereotactic Radiosurgery For Brain Metastases

Objective:Brain metastasis(BM)is a common event during the development of many cancers,and is also one of the main causes of death of tumor patients.Stereotactic radiosurgery(SRS)is an effective treatment for BMs.The prognostic effects of various clinical factors on local control(LC)and overall survival(OS)after SRS treatment are still unclear.The purpose of this study is to retrospectively analyze the intracranial progression free survival(i PFS)and OS of patients receiving SRS treatment,and explore the relationship between various clinical characteristics and patient prognosis.Methods:We collected the clinical information of patients who were diagnosed with BM and received SRS treatment in our center between 2018 and 2021.Univariate and multivariate Cox regression analysis and KM analysis for i PFS and OS were conducted in R software to investigate the prognostic effects of clinical characteristics.Baseline difference between two groups was balanced through Propensity Score Matching method.Results:In total,189 patients that received SRS in our center were enrolled in the cohort.The median i PFS for all patients was 8.93 months(95%CI 6.9-10.6),while the median OS was 16.5 months(95%CI 12.7-20.5).Multivariate Cox analysis showed that the number of BM>=5(HR 1.83[95%CI 1.28-2.61],<0.001)and receiving target therapy(HR 0.64[95%CI 0.45-0.91],p=0.014)were closely related to i PFS.ECM PR/SD(HR0.67[95%CI 0.45-0.99],p=0.045),BM number>=5(HR 1.50[95%CI 1.01-2.23],p=0.045),receiving target therapy(HR 0.63[95%CI 0.42-0.96],p=0.032),was associated with OS.Peritumoral edema and SRS fractionation were not associated with the prognosis.Subgroup analysis showed that patients with cumulative intracranial tumor volume(CITV)>=2.14cm~3and number>=5 had shortest i PFS(P<0.001)and OS(P=0.006),compared with other subgroups.For patients with more than 5 BMs,SRS plus whole brain radiotherapy(WBRT)can achieve better local control,compared with SRS alone group,both before PSM(P=0.041)and after PSM(P=0.029).Conclusion:BM number and target therapy were associated with i PFS and OS after SRS.ECM PR/SD was associated with OS.The prognosis of patients in the subgroup with larger CITV and more BMs was the worst.For patients with more than 5 BMs,the combination of SRS and WBRT can improve the local control,but can not prolong the OS of patients.