Stereotactic radiotherapy for brain metastases in patients with lung cancer; outcome and toxicity in clinical practice.

Background: Stereotactic radiotherapy (SRT) is an established modality for treating limited brain metastases (BMs). This study aimed to assess the real-life treatment outcome and associated prognostic factors for survival in a consecutive lung cancer cohort receiving SRT for BMs. Materials and methods: A retrospective review and analysis of patients with lung cancer with BMs treated with SRT in western Sweden between 2002 and 2017 were performed. Data were collected from patient charts and the radiotherapy dose planning system. Results: One hundred nine patients corresponding to 139 lesions were assessed; the majority were treated with single-fractionated SRT with 20 Gy. The median overall survival (OS) was 6.1 months, with a 12-month survival rate of 24%. The estimated overall disease control rate (DCR) was 84% at a median time of three months. On multivariate analysis, WHO performance status (PS) (p = 0.002) and smoking status (p = 0.005) were significant predictive factors for survival. Four percent of the patients experienced possible grade III-IV toxicity, and previously administered cranial radiation therapy was a significant independent factor (p = 0.03) associated with the risk of developing acute toxicity. Conclusions: SRT due to brain metastases from lung cancer is a well-tolerated treatment. When selecting patients suitable for treatment, PS and extracranial disease progression should be considered. Smoking cessation is probably of value even in this palliative setting. The goal of SRT for BMs is not only to improve survival but also to provide symptom relief, and future studies on SRT should assess patient-reported outcomes in addition to survival.