Clinical Outcomes and Prognostic Factors of Fractionated Stereotactic Radiation Therapy for Large Brain Metastases as a Potential Alternative to Surgery

Abstract

\n Introduction: We investigated the outcomes and prognostic factors for fractionated stereotactic radiation therapy (FSRT) for large brain metastases and evaluated whether FSRT could negate the need for surgery, which is the mainstream treatment for large brain metastases.Methods: Patients with brain metastases measuring ≥2 cm treated with FSRT were retrospectively examined. Patients undergoing FSRT postoperatively were excluded. Local failure, intracranial failure, and adverse events were evaluated.Results: Overall, 106 lesions in 98 patients were evaluated. Performance status was 0–1, 2–4, and unknown in 79, 25, and 2 patients, respectively. The median maximum tumor diameter was 25 mm, and the median prescription dose was 35 Gy in 3 fractions. The median follow-up period after FSRT was 7 months. The 1-year rates of local failure, intracranial failure, and overall survival were 13.0%, 57.8%, and 48.0%, respectively. In multivariate analysis, the maximum dose for target ≥135 Gy (biological equivalent dose of a/b of 10 Gy) and good performance status were independent positive prognostic factors for local failure. Sixteen patients (16.3%) were treated with whole-brain radiotherapy after FSRT owing to multiple intracranial recurrences, while surgery was performed for three patients (3.1%) owing to local recurrence.Conclusions: FSRT for large brain metastases achieved good local control and only 3% of patients needed surgery after FSRT, suggesting that FSRT is a potential alternative to surgery. In FSRT, a higher maximum tumor dose was useful for local control.