Clinical Outcomes and Prognostic Factors of Fractionated Stereotactic Radiosurgery for Brain Metastases ≥20 mm as a Potential Alternative to Surgery

Abstract

This study investigated the outcomes and prognostic factors of fractionated stereotactic radiosurgery (FSRS) for treatment of brain metastases (BMs) ≥20 mm and determined whether FSRS could replace surgery, the primary treatment for large BMs. Patients with BMs ≥20 mm treated with FSRS were retrospectively examined. Patients who underwent FSRS postoperatively were excluded. Local failure, intracranial failure, and adverse events were evaluated. Overall, 116 lesions in 105 patients were evaluated. The performance status was 0-1, 2-4, and unknown for 86, 28, and 2 patients, respectively. The median maximum tumor diameter was 25 mm, and the median prescribed dose was 35 Gy in 3 fractions. The median follow-up period after FSRS was 8 months. The 1-year local failure, intracranial failure, and overall survival rates were 12.5%, 56.6%, and 49.0%, respectively. A maximum dose of ≥135 Gy (biological equivalent dose [α/β= 10 Gy]) and good performance status were independent favorable prognostic factors for local control. After FSRS, 21 (20%) patients were treated with whole-brain radiotherapy because of multiple intracranial recurrences, and 4 (3.4%) patients underwent surgery because of local recurrence. FSRS for BMs ≥20 mm achieved good local control. Only 3.4% of patients required surgery after FSRS, suggesting that FSRS is a potential alternative to surgery. For FSRS, a higher maximum tumor dose was useful for local control.