Efficacy of stereotactic radiotherapy as salvage treatment for recurrent malignant gliomas.

PURPOSE To evaluate the efficacy and toxicity of CyberKnife stereotactic radiotherapy (SRT) for recurrent glial tumors previously treated with high-dose radiotherapy. METHODS CyberKnife SRT was performed in 37 patients with recurrent glial tumors who presented to our hospital between January 2007 and March 2012. The patients were subjected to a dose ranging from 20 to 28 Gy using the CyberKnife system with an average of two fractions. The median follow-up duration after SRT was 14 months (range 1.8-57). RESULTS The median survival time of the patients after recurrence was 22.3 months (95% confidence interval/95% Cl 12.5-32). The median survival times of the high- and low-grade patients were 29 and 19 months, respectively. No significant toxicity due to radiation was noticed during the follow-up period. No factor influencing mortality was found in either the univariate or multivariate analysis. CONCLUSION SRT using CyberKnife is an effective and safe treatment choice for recurrent glial tumors. SRT achieves a more favorable outcome in the treatment of recurrent tumors, particularly in high-grade ones.