Feasibility of Salvage Re-irradiation With Stereotactic Radiotherapy for Recurrent Glioma Using CyberKnife

Aim: To evaluate the toxicity and efficacy of re-irradiation with salvage stereotactic radiotherapy (SRT) for recurrent glioma using CyberKnife. Patients and Methods: This study retrospectively investigated 35 patients with 48 recurrent grade 2-4 gliomas who received SRT between 1998 and 2011. Six patients (17.1%) had grade 2 gliomas, nine (25.7%) had grade 3 gliomas, and 20 (57.1%) had glioblastomas; all initially underwent surgery and conventional radiotherapy. The median initial and subsequent radiotherapy doses were 60 and 26 Gy, respectively. Results: After a median follow-up period of 9.0 months, the only toxicity of grade 2 or more was radiation-induced brain necrosis in four patients (11.4%). The median overall and progression-free survival periods following re-irradiation were 9.0 and 3.0 months, respectively. Univariate analysis revealed that performance status at salvage re-irradiation was a significant predictor of progression-free survival. Conclusion: Salvage re-irradiation using CyberKnife is feasible, with an acceptable toxicity profile, for patients with recurrent glioma.