Fractionated repeat Gamma Knife stereotactic radiosurgery for locally recurrent brain metastases.

Introduction: Survival of patients with brain metastases (BMs) is increasing. Consequently, local disease recurrence of previously treated BMs has become more prevalent. Stereotactic radiosurgery (SRS) has been employed as a salvage therapy; however, concerns over adverse radiation events (AREs) persist. Utilization of a fractionated approach may reduce AREs in this population. Methods: A retrospective review of locally recurrent BMs was conducted. The primary outcome was local control and AREs. Utilizing the Kaplan–Meier method, we analyzed the time to local control (LC) and overall survival (OS) for each recurrent lesion treated with SRS. Cox regression analysis was employed to examine predictors of LC and OS. Results: Our cohort consisted of 45 patients with a median age of 62 years [interquartile range (IQR): 56.3–68.0]. The median lesion volume at the time of repeat SRS was 3.3 cm3 (IQR: 0.75– 8.8). Patients were treated with a median prescription dose of 27.0 Gy (IQR: 25.0–30.0) over a median of five fractions (range: 3–5). Actuarial LC rates at 3, 6, 12, and 24 months were: 79.4%, 72.2%, 61.7%, and 54.9%, respectively. There was no ≥grade 3 treatment toxicity reported. On univariate analysis Karnofsky performance status: >70 (HR: 0.17, 95% CI: 0.06–0.5, p = 0.001) and the presence of extracranial disease at SRS (HR: 2.7, 95% CI: 1.04–6.97, p = 0.04) were significantly associated with overall survival (OS). Conclusions: Repeat fractionated SRS is safe and efficacious for locally recurrent BMs. Performance status and systemic disease control are predictors of OS in this population. [ABSTRACT FROM AUTHOR]