Frameless Cyberknife radiosurgery for metastatic and primary brain tumors

Abstract

11527 Background: Cyberknife delivers image-guided stereotactic radiation to intracranial and extracranial skull base tumors without a frame. This frameless feature makes Cyberknife a completely non-invasive procedure and allows non-surgical neuro-oncology personnel to treat patients with tumors in the neuraxis. Methods: Patients with intracranial tumors were selected from our Brain Tumor Clinic if they were not surgical candidates or had residual tumors after neurosurgery. The decision for Cyberknife radiosurgery was made after careful review of all available treatment options in our multidisciplinary brain tumor conference based on patients’ history and neurologic findings, neuroimaging data, and pathology. All patients signed informed consent prior to fusion head MRI and CT scanning. They were pre-medicated with 4 mg of dexamethasone and 500 mg of levetiracetam twice daily. All dose plans were calculated based on CT images acquired from 1.25-mm slices with an inverse planning technique. Dynamic tracking software monitored patient movements and adjusted the robotic arm accordingly, compensating for patient motion up to 10 mm in translation and 5 degree in rotation. Results: Nine subjects with 15 treatment targets, including 4 meningiomas, 1 high-grade glioma, 1 plasmacytoma, and 3 melanomas, were treated with single-fraction or 5 fractions of Cyberknife radiosurgery. No acute toxicity was seen during or within 24 hours of treatment. One subject developed subacute onset of cerebral edema 2 weeks after the procedure but his symptoms were quickly reversed with dexamethasone. Conclusions: Cyberknife radiosurgery is a well-tolerated procedure for intracranial and extracranial tumors in the skull base. Neuro-oncologist, with the appropriate training, could perform Cyberknife radiation planning with radiation oncologists and physicists. No significant financial relationships to disclose.