Brain metastases of lung cancer: comparison of survival outcomes among whole brain radiotherapy, whole brain radiotherapy with consecutive boost, and simultaneous integrated boost

Radiotherapy is the mainstay for treating brain metastasis (BM). The objective of this study is to evaluate the overall survival (OS) of patients with BM of lung cancer treated with different radiotherapy modalities. Patients with BM of lung cancer who underwent radiotherapy between July 2007 and November 2017 were collected, and their baseline demographics, clinicopathological characteristics and treatments were recorded. Survival was estimated by the Kaplan–Meier method and compared by using the log-rank test. Univariate and multivariate analysis of the prognostic factors were performed using the Cox proportional hazard regression model. A total of 144 patients were enrolled, of whom 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 OS in SIB-IMRT group was significantly longer than that in WBRT group (median OS 14 (95% confidence interval [CI] 8.8–19.1) vs.7 (95% CI 5.5–8.5) months, log-rank p < 0.001) and WBRT + boost group (median OS: 14 (95% CI 8.8–19.1) vs.11 (95% CI 8.3–13.7) months, log-rank p = 0.037). Multivariable analysis showed that mortality risk of patients treated with SIB-IMRT decrease by 56, 59, 64 and 64% in unadjusted model (hazard ratio [HR] = 0.44; 95% CI 0.28–0.70, p < 0.001), model 1 (HR = 0.41; 95% CI 0.26–0.65, p < 0.001), model 2 (HR = 0.36; 95% CI 0.21–0.61, p < 0.001), and model 3 (HR = 0.36; 95% CI 0.21–0.61, p < 0.001). For patients with BM of lung cancer, SIB-IMRT seems to be associated with a more favorable prognosis.