Analysis On The Effects And Prognostic Of Simultaneous Integrated Boost With Intensity-modulated Radiation Therapy In Lung Cancer With Brain Metastases

[Objective]To evaluate the efficacy of simultaneous integrated boost with intensity-modulated radiation therapy (IMRT) in the treatment of patients with brain metastasis(BM) from lung cancer, and investigate prognostic factors.[Methods]A retrospective database of52patients treated for BM from lung cancer betweenJune2009and June2012in our hospital received IMRT. Patients with KarnofskyPerformance Status(KPS)≥70,the Biologically effective dose（BED）of whole-brainradiation therapy(WBRT) was31.25-55.2Gy，the Biologically effective dose of BMwas46.88-78.13Gy.Radiation therapy oncology group （RTOG） Brain tumorradiotherapy response evaluation index and Response Evaluation Criteria in SolidTumors(RECIST, version1.1) were adopted in the assessment of the effects afterradiotherapy. Twelve additional potential prognostic factors were investigated: gender,age, tumor type, KPS, extracranial metastases status, control of primary tumor,number of BM, interval between initial BM diagnosis and radiotherapy, with orwithout chemotherapy, Diagnosis-Specific Graded Prognostic Assessment(DS-GPA),Biologically effective dose of WBRT and Biologically effective dose of BM.Survival rate was calculated by Kaplan-Meier method. Log-rank method was adoptedin the univariate analysis. The multivariate analysis about survival was performedwith Cox’s regression proportional model.[Results]The median follow-up time was14months, the Follow-up rate was92.3%(4/52).The clinical symptom remission rate was92.3%(48/52, CR32cases+PR16cases).Only80.8%（42/52）of the patients reexamination with brain CT or MRIin3months after radiotherapy. The response rate was33.3%(14/42, CR1case+PR13cases).The median survival time was14months, while6months,1year survival rate was86.5％and65.3％respectively．Univariate analysis show that the BMBiologically effective dose≥56Gy arms revealed a superior survival time withBiologically effective dose＜56Gy arms（(P=0.029）.Cox multivariate analysis showthat the Biologically effective dose of BM was a independent prognostic factor foroverall survival in the brain metastases(P=0.038).[Conclusion]Simultaneous integrated boost with IMRT in the treatment of patients with brainmetastasis from lung cancer is safe and effective. IMRT can alleviate clinicalsymptoms in patients with brain metastases from lung cancer. Lung cancer with BMBiologically effective dose more than56Gy of patients may have a better survival.