Long term outcome with post-operative radiation therapy for spinal canal ependymoma

Purpose: A retrospective study was performed to evaluate the long term efficacy and safety of post-operative radiation therapy in the management of spinal canal ependymoma at our institution. Methods and materials: Between 1954 and 1997, 22 patients with spinal canal ependymoma were treated with post-operative radiotherapy at our institution. The median age at diagnosis was 34.7 years (range 9.8-56.1 years). All patients underwent open biopsy with histologic diagnosis: 13 patients (59%) had ependymoma (WHO Grade II) and 9 patients (41%) had myxopapillary ependymoma (WHO Grade I). The median tumor size was 4.0 cm (range 1.5-15.0 cm). Twenty patients received subtotal resection and 2 patients received gross-total resection. Median radiation dose was 45.0 Gy. Results: The median follow up for surviving patients was 11.4 years (range 0.6-37.0 years). An 80% progression-free-survival (PFS) was observed for all patients at 5-, 10- and 15-year endpoints. All recurrences were within 3 years of treatment. The 5-, 10- and 15-year overall-survivals (OS) for all patients were 85%, 78% and 64%, respectively. Patients with tumors larger than 6.0 cm at time of presentation demonstrated 5- and 10-year PFS of 58.3% compared to 92.3% for patients with tumors 6.0 cm or smaller (P = 0.047). There was no significant correlation between tumor size and OS. Conclusions: Post-operative radiation after subtotal resection is safe and offers durable tumor control and long term patient survival.