Outcome and prognostic factors for older patients undergoing radiosurgery for brain metastases

Purpose Older patients with brain metastases (BM) are often excluded from clinical trials. The aim of our study was to investigate the outcomes following Gamma Knife radiosurgery (GKRS) in young old (65–74 years) and very old (≥75 years) patients with BM. Methods Between October 2012 and October 2018, we treated 89 patients aged ≥65 years with GKRS. Patients were divided in two group: young old (YO) and very old (VO) patients. At baseline G8, Graded Prognostic Assessment (DS-GPA) and Basic Score for Brain Metastases (BSBM) were assessed for all patients. Survival analysis was estimated using the Kaplan-Meier (KM) method. Cox regression model was used to investigate the influence of significant factors on KM. Results Median age at the time of GKRS was 72.2 years (range 65–87). A mean of 2.52 lesions were treated per patient (range 1–14). Median overall survival (OS) for YO and VO patients was 14.2 and 15.7 months, respectively. At univariate analysis, there were no significant differences in OS between the two age groups. A high BSBM (p ≤ .0001) and a high DS-GPA score (p = .0069) were associated with longer survival. A low DS-GPA score was the most powerful independent factor for predicting short survival (HR 1.76, 95% CI 1.25–2.46, p = .001) at multivariate analysis. Conclusion GKRS is a safe approach to treat BM in elderly patients. DS-GPA score represents an important prognostic factor for survival in elderly patients undergoing GKRS.