The Clinical Results of Radiation Therapy for Spinal Cord Ependymoma with Adverse Prognostic Features: A Single-Institution Experience

Abstract

The primary treatment for spinal ependymoma is surgical resection. However, some cases cannot achieve complete resection because of either neurological compromise or disseminated feature. In these cases, radiotherapy (RT) is generally recommended, however, the role of RT has not been fully elucidated. This study evaluated the clinical outcome of RT on spinal ependymoma with the adverse feature, such as incomplete resection or disseminated disease. Between 1991 and 2016, 25 patients with spinal cord ependymoma treated with radiotherapy (RT) in a single institution were retrospectively reviewed. All except one patient with anaplastic ependymoma had gross disease in spinal MRI before RT. Eighteen (64%) underwent subtotal resection, while 6 (24%) did not undergo surgical resection. Six (24%) had multiple disseminated diseases. World Health Organization grade was I in 12 patients, II in 12 patients, and III in 1 patient. Nineteen (76%), 5 (20%), and 1 (4%) patients received RT to the localized disease, craniospinal area, and whole spinal cord with posterior cranial fossa, respectively. Median RT dose was 50.4 Gy (range, 44.0–59.4). With a median follow-up period of 49 months (range, 9–321 months), disease progression was observed in 4 patients, of whom 2 had clear cell ependymoma (grade II), and 2 had classic ependymoma (grade II). There was no failure or death in 12 patients with grade I ependymoma. Of 6 patients with disseminated disease, 3 had not experienced disease progression with follow-up of 111 months, 45 months, and 49 months, respectively. Of 18 patients with localized disease, 16 had not experienced disease progression until the last follow-up. In all patients, the 2- and 5-year progression-free survival rates were 91.7% and 79.6%, respectively, and overall survival rates were 95.7% and 83.7% respectively. Of patients with grade I ependymoma, the 2- and 5-year overall survival rates were 100%, while those were 91.7% and 69.4%, respectively, in patients with grade II or III ependymoma. Twelve (48%) showed improved neurologic function after RT. Late toxicity (hypopituitarism) occurred in 1 patient who received craniospinal irradiation. Favorable PFS and OS could be achieved with RT in spinal ependymoma with adverse features. RT appears to be an effective treatment option for spinal ependymoma in cases when complete tumor removal cannot be achieved.