Analysis of prognostic factors and comparison of prognostic index scores in patients with brain metastases after whole-brain radiotherapy.

BACKGROUND AND PURPOSE Brain metastases (BMs) are typically associated with poor patient prognosis. Radiation therapy remains the primary treatment for BMs, and patient's prognosis is affected by many factors. The aim of this study was to identify prognostic factors and to compare prognostic index scores in patients with BMs who received whole-brain radiotherapy (WBRT). METHODS A retrospective prognostic study was conducted in 125 patients with BMs who underwent WBRT between Jan 2008 and Jul 2011. The significance of prognostic variables with regard to survival was determined using univariate and multivariate analyses. A prognostic index (PI) was established based on Cox regression analysis and subgrouping values. The recursive partitioning analysis classes (RPA), basic score for brain metastases (BS-BM), Graded Prognostic Assessment index (GPA), and PI were assessed with regard to prognosis. RESULTS The median survival time was 213 days (7.1 months). In the univariate analysis of the test group, survival was significantly associated with Karnofsky performance status (KPS) score, the number of BMs, the presence of extracranial metastases, primary tumor status and the number of involved extracranial organs. The multivariate analysis showed that the KPS score (P = 0.002, Wald = 9.700), presence of extracranial metastases (P = 0.018, Wald = 5.604) and primary tumor status (P = 0.001, Wald = 10.212) were significantly correlated with overall survival. RPA, BS-BM and GPA were all closely related to prognosis, as determined using a log-rank test. In predicting the 3- and 6-month survival for patients, the PI was superior to the other three modes. CONCLUSIONS The three indexes, RPA, BS-BM and GPA, are valid prognostic index models; however, the PI model was the most powerful.