Radiosurgery using the Cyberknife for benign spinal tumors: Korea Cancer Center Hospital experience

Abstract

This study evaluated clinical outcome and safety of radiosurgery using the Cyberknife for treatment of benign spinal tumors. The authors treated 30 benign spinal tumors in 20 patients with the Cyberknife (Accuray, Inc., Sunnyvale, CA, USA) from 2002 to 2008. Among these there were 20 neurogenic tumors, eight hemangioblastomas, and two meningiomas. Four patients with neurofibromatosis (NF) type 2 and four patients with Von Hippel Lindau disease were also included. Radiosurgery was done as primary treatment for 22 lesions, for postoperative residual tumor control for four lesions, and for the remaining four lesions with image-based progression after initial subtotal resection. The distribution of lesions was cervical (18 tumors), thoracic (six), and cauda equina level (six). Follow-up data included imaging studies, clinical findings, and radiotherapy data. Tumor volume ranged from 0.04 to 33.65 cm³ (mean, 4.52 cm³). A 14-33 Gy marginal dose was delivered in 1-5 fractions. The mean follow-up period was 35.6 months (range, 12-84 months). On follow-up, most lesions decreased in size (57%) or remained unchanged (33%). Two lesions initially decreased, then increased later. One lesion increased without response. With regard to clinical aspects, radicular pain and myelopathic pain improved after radiosurgery in most cases (94%). Motor weakness recovered in two out of five patients and recovery of sensory change occurred in four out of ten patients. In two patients, symptoms were aggravated by tumor enlargement and the occurrence of new lesion. Mean spinal cord volumes receiving more than 10 and 8 Gy were 0.40 ± 0.4 and 0.81 ± 0.7 cm³, respectively. Stereotactic radiosurgery (SRS) using the Cyberknife showed the ability to control benign spinal tumors without complication in most cases.