Prognostic Significance Of Whole Brain Radiotherapy,Whole Brain Radiotherapy With Consecutive Boost,and Simultaneous Integrated Boost In Brain Metastases Of Lung Cancer

Objectives: Radiotherapy is the mainstay for brain metastases.The objectives of this study are to investigate the effects of different radiotherapy modalities and clinicopathological factors on the prognosis of patients with brain metastases of lung cancer,and to provide evidence for the option of radiotherapy modalities for patients with brain metastases.Methods: Patients with brain metastases of lung cancer who underwent radiotherapy at the Fourth Affiliated Hospital of China Medical University from July 2007 to November 2017 were collected,and their baseline demographics,disease characteristics and radiotherapy modalities were recorded.All statistical analyses were performed using the SPSS 24.0 and R 3.4.3 software.Survival was estimated by the Kaplan-Meier method and compared by using the log-rank test.Multivariate analysis of the prognostic factors was performed using the Cox proportional hazard regression model.Results: A total of 144 patients(90 males and 54 females;median age 59 years)were included,of which 77 underwent whole-brain radiotherapy(WBRT),39 underwent whole brain radiotherapy with consecutive boost(WBRT+boost),and 28 underwent integrated simultaneous integrated boost intensity-modulated radiotherapy(SIB-IMRT).The post-brain metastases survival(PBMS)in SIB-IMRT group was longer than that in WBRT group(median time 14(95% CI 8.8-19.1)vs 7(95% CI 5.5-8.5)months,P <0.001)and WBRT+boost group(median time 14(95% CI 8.8-19.1)vs 11(95% CI 8.3-13.7)months,P = 0.037).Overall survival(OS)in SIB-IMRT group was longer than WBRT group(median time 26(95% CI 14.8-37.2)vs 14(95% CI 9.2-18.8)months,P <0.001).Univariate analysis showed that radiotherapy modality,gender,smoking status,histopathology,extracranial metastasis status when brain radiotherapy,recursive partitioning analysis(RPA)class,lung diagnosis-specific graded prognostic assessment(DS-GPA)score and brain metastasis-free interval(BMFI)were associated with PBMS and OS.On multivariate analysis,smoking status,radiotherapy modality,RPA class,lung DS-GPA score and BMFI maintained significance in PBMS,histopathology,radiotherapy methods,RPA class and BMFI maintained significance in OS.Conclusions: For patients with brain metastases of lung cancer,brain radiotherapy modality is one of the important and independent prognostic factors.SIB-IMRT seems to be associated with survival benefits as compared with WBRT and WBRT+boost.