Efficacy of stereotactic radiosurgery as a salvage treatment for recurrent malignant gliomas

BACKGROUND. The objective of this prospective cohort study was to determine the efficacy of stereotactic radiosurgery (SRS) as a salvage treatment in patients with recurrent malignant gliomas. METHODS. Between January 2000 and December 2006, 114 consecutive patients were treated with SRS as a salvage treatment for recurrent malignant gliomas at a single institution. Clinical outcome and its prognostic factors were analyzed and compared with the historical control group who were treated at the same institution between 1995 and 1999. RESULTS. The median overall survival from the time of diagnosis was 37.5 months (95% confidence interval [95% CI], 11.7-63.2 months) for patients with grade 3 gliomas (according to World Health Organization criteria) and was 23 months (95% CI, 16.2-29.3 months) for patients with glioblastomas. The median progression-free survival after SRS was 8.6 months (95% CI, 1.1-16.2 months) for patients with grade 3 gliomas and 4.6 months for patients with glioblastomas (95% Cl, 4.0-5.2 months). With regard to treatment-related complications, radiation-induced necrosis was observed in 22 of 114 patients (24.4%). Compared with this historic control group, SRS significantly prolonged survival as a salvage treatment in patients with recurrent glioblastomas (23 months vs 12 months; P <.0001), but it was not found to provide a significant surgical benefit in patients with recurrent grade 3 gliomas (37.5 months vs 26 months; P =.789). On univariate analysis of prognostic factors, tumor volume (<10 mL) and low histologic grade were found to significantly influence better survival (P =.009 and P=.041, respectively). CONCLUSIONS. SRS is a safe and effective modality in selected patients with recurrent small-sized glioblastomas. However, the efficacy of SRS for recurrent grade 3 gliomas needs to be further evaluated in well-designed clinical studies.