The objective of the study was to evaluate the outcomes in terms of efficacy and safety of a large consecutive series of 362 patients with renal cell carcinoma (RCC) brain metastases treated using stereotactic radiosurgery (SRS) in the tyrosine kinase inhibitor (TKI) era.
From 2005 to 2015, 362 consecutive patients with brain metastases from RCC were treated using SRS in 1 fraction: 226 metastases (61 patients) using Gamma-Knife at a median of 18 Gy (50% isodose line); 136 metastases (63 patients) using linear accelerator at a median of 16 Gy (70% isodose line). The median patient age was 58 years. At the first SRS, 37 patients (31%) received a systemic treatment. Among systemic therapies, TKIs were the most common (65%).
The local control rates were 94% and 92% at 12 and 36 months, respectively. In multivariate analysis, a minimal dose >17 Gy and concomitant TKI treatment were associated with higher rates of local control. The overall survival rates at 12 and 36 months were 52% and 29%, respectively. In multivariate analysis, factors associated with poor survival included age ≥65 years, lower score index for SRS, concomitant lung metastases, time between RCC diagnosis and first systemic metastasis ≤4 months, occurrence during treatment with a systemic therapy, no history of neurosurgery, and persistence or occurrence of neurological symptoms at 3 months after SRS. Seventeen patients had Grade III/IV adverse effects of whom 3 patients presented a symptomatic radionecrosis.
SRS is highly effective in patients with brain metastases from RCC. Its association with TKIs does not suggest higher risk of neurologic toxicity.