Efficacy of X-ray stereotactic radiotherapy on brain metastases and prognostic analysis.

Background and Objective: X-ray stereotactic radiotherapy (SRT) is one of the effective treatments for brain metastases (BM). This study was to evaluate the efficacy of SRT on BM, and investigate prognostic factors.
Methods: Between July 1999 and December 2004, a total of 122 intracranial lesions in 78 patients with BM were treated using SRT in our Center. Forty-nine patients had a solitary lesion and 29 had multiple (2-6) lesions. The median SRT dose was 15 Gy (11-24 Gy) in single fraction for 38 lesions, and 24 Gy (11-40 Gy) in 2-6 fractions for 84 lesions. SRT was combined with whole brain radiotherapy (WBRT) of 30-40 Gy for 39 patients. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier method. Univariate and multivariate analyses were performed by the log-rank test and Cox model, respectively.
Results: The median survival time was 12.9 months (1.7-77.4 months). The 1-year intracranial PFS rate was 87.4%. The 1-and 2-year OS rates were 53.9% and 25.8%, respectively. Univariate analysis showed that the 1-year OS rates were higher in the patients with pretreatment KPS of >/= 70, extracranial lesions controlled, or SRT combined with WBRT than in those with KPS of < 70 (60.7% vs. 29.4%, P = 0.002), extracranial lesions uncontrolled (69% vs. 44.9%, P = 0.005), or SRT alone (64.1% vs. 43.4%, P = 0.03). The benefit of treating with WBRT in combination was mainly achieved in the patients with extracranial lesions controlled or with more than one intracranial lesion. Multivariate analysis showed that KPS score and status of extracranial lesions were independent prognostic factors for OS.
Conclusions: SRT is an effective and safe modality for BM. SRT combined with WBRT may prolong the survival time of the patients with extracranial lesions controlled or multiple intracranial lesions. Independent prognostic factors for OS are KPS score and status of extracranial lesions.