Gamma Knife radiosurgery for brain metastasis: review of 103 patients

Abstract

Objective: To assess clinical and imaging outcomes in patients treated with Gamma Knife stereotactic radiosurgery (SRS) for brain metastasis. Methods: One hundred and three patients with 158 intracranial metastasis consecutively underwent Gamma Knife SRS between January, 2004 and December, 2006. The results were based on last imaging and the date of the last visit. Average age of the patients was 56 years (range 32-84 years). Karnofsky performance status average was 87.6. Fifty-eight (56.3%) patients had single brain metastasis. The average tumor volume was 2.5cc (range 0.02-16.6 cc). The SRS marginal dose average was 23.4 Gy (range 15-25 Gy). Results: Treatment sequence was SRS alone (89 patients) or SRS plus whole-brain radiotherapy (WBRT) (14 patients). The 1-year local control was 80%, being better for tumors with volume <5cc than for ≥5 cc: 86% vs 53% (p<0.05). The 1-year distant brain metastasis-free survival incidence was 73%. The initial number of brain lesions (single vs multiple) was not a significant factor on distant brain metastasis: free survival at 1 year was 75% for single metastases and 70% for multiple lesions. Renal cancer was the only factor with a significant effect on distant brain metastasis. The median overall survival was 15 months. According to unifactorial and multifactorial analysis, three prognostic factors for overall survival were retrieved recursive partitioning analysis (RPA) class, Karnofsky index performance and tumor volume. Conclusion: In this series, SRS provided excellent local control with relatively low morbidity in patients with brain metastases.

Keywords

• brain metastasis
• radiosurgery
• gamma knife