Volumetric Modulated Arc Therapy for Radiosurgery of Brain Metastases: A Single-Center Study

Whole-brain radiation therapy and stereotactic radiosurgery are two treatment modalities commonly utilized to treat brain metastases (BMs). The aim of this study is to retrospectively analyze the main radio-oncologic and clinical-demographic aspects of a cohort of BM patients treated with Volumetric Modulated Arc Therapy for radiosurgery (VMAT-RS). This is a cross-sectional observational design study with a retrospective review of the medical records of patients with brain metastases treated with VMAT-RS between 2012 and 2018. Clinical and demographic data, with special attention to sex, age, primary tumor, brain tumor-related epilepsy (BTRE), number and brain location of BMs, Karnofsky Performance Status (KPS), the updated DS-GPA prognostic index, and the survival estimated according to the Kaplan-Meier model from the date of radiosurgery, were analyzed. One hundred and twenty-one patients with 229 BMs were treated with VMAT-RS. Patients presented 1-4 BMs, which were treated with five non-coplanar VMAT arcs. Sixty-eight percent of the patients had lung cancer, and 35% of the BMs were in the frontal lobe. The proportion of local control was 88.5%. BTRE prevalence was 30.6%. The median survival time (MST) was 7.7 months. In the multivariate analysis of the Cox regression model, KPS >= 70 (HRKPS < 70 = 2.59; p = 0.001) and higher DS-GPA (HRDS-GPAII = 0.55, p = 0.022; HRDS-GPAIII-IV = 0.38, p = 0.006) were associated with improved survival. In the univariate analysis, primary tumor, age, and the presence of metastases in the posterior fossa (PFBMs) were also significant. In conclusion, the VMAT-RS is a technique with an overall survival rate comparable to other radiosurgery techniques. The median survival is significantly longer for those with higher KPS and DS-GPA. Other variables, such as the type of primary tumor, age, and PFBMs, could also influence survival, although further studies are needed.