GliaSite brachytherapy for treatment of recurrent malignant gliomas: a retrospective multi-institutional analysis.

Objective: To review the cumulative experience of 10 institutions in treating recurrent malignant gliomas with the brachytherapy device, GliaSite Radiation Therapy System.

Methods: The patient population consisted of 95 patients with recurrent grade 3 or 4 gliomas, a median age of 51 years, and a median Karnofsky performance status score of 80. All patients had previously undergone resection and had received external beam radiotherapy as part of their initial treatment. After recurrence, each patient underwent maximal surgical debulking of their recurrent lesion and placement of an expandable balloon catheter (GliaSite) in the tumor cavity. The balloon was afterloaded with liquid I (Iotrex) to deliver a median dose of 60 Gy to an average depth of 1 cm with a median dose rate of 52.3 Gy/hr. Patients were carefully followed with serial magnetic resonance imaging and monthly examinations for tumor progression, side effects, and survival.

Results: The median survival for all patients, measured from date of GliaSite placement, was 36.3 weeks with an estimated 1 year survival of 31.1%. The median survival was 35.9 weeks for patients with an initial diagnosis of glioblastoma multiforme and 43.6 weeks for those with non- glioblastoma multiforme malignant gliomas. Analysis of the influence of various individual prognostic factors on patient survival demonstrated that only Karnofsky performance status significantly predicted for improved survival. There were three cases of pathologically documented radiation necrosis.

Conclusion: Reirradiation of malignant gliomas with the GliaSite Radiation Therapy System after reresection seems to provide a modest survival benefit above what would be expected from surgery alone. This report not only confirms the initial results of the feasibility study but provides evidence that similar outcomes can be obtained outside of a clinical trial.