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Int. J. Radiation Oncology Biol. Phys., Vol. 42, No. 5, pp. 953–958, 1998 Copyright © 1998 Elsevier Science Inc. Printed in the USA. All rights reserved 0360-3016/98/$–see front matter

PII S0360-3016(98)00350-2

● Clinical Investigation

THE RESULTS OF RADIOTHERAPY FOR EPENDYMOMAS: THE MAYO CLINIC EXPERIENCE S TEVEN E. S CHILD , M.D.,* K URT N ISI , M.D., † B ERND W. S CHEITHAUER , M.D., ‡ W ILLIAM W. W ONG , M.D.,* M ARK K. L YONS , M.D., § P AULA J. S CHOMBERG , M.D., † AND E DWARD G. S HAW , M.D. \ Mayo Clinic Arizona, Departments of *Radiation Oncology and § Neurosurgery, Scottsdale, AZ; Mayo Clinic, Departments of † Radiation Oncology and ‡ Pathology, Rochester, MN; and \ Wake Forest University School of Medicine, Winston-Salem, NC Purpose: This analysis was performed to examine the outcome of patients with histologically confirmed ependymomas of the brain or spinal cord who received postoperative radiotherapy. Methods and Materials: Eighty patients with histologically confirmed ependymomas were evaluated retrospec- tively. All were treated with various combinations of surgery, radiotherapy (RT), and chemotherapy. Follow-up ranged from 5 to 30 years (median 10.4 years). Results: The 5- and 10-year survival rates for the entire study group were 79% and 73%, respectively. Patients with low-grade (1 and 2 of 4) tumors had a 5-year survival rate of 87% as compared to 27% for those with high-grade (3 and 4 of 4) tumors ( p < 0.0001). Patients with tumors of the spine had a 5-year survival rate of 97% as compared to 68% for those with infratentorial tumors, and 62% for those with supratentorial tumors ( p 5 0.03). Patients with myxopapillary ependymomas of the spine had a 5-year survival rate of 100% as compared with 76% for patients with other histological subtypes of ependymoma ( p 5 0.02). Multivariate analysis revealed that the survival rate was independently associated with tumor grade ( p 5 0.0007) and histological subtype ( p 5 0.02). Twenty-eight patients (35%) experienced local failure and 10 patients (13%) developed leptomeningeal seeding. The 5-year leptomeningeal failure rate was 10% in patients with low-grade tumors as compared to 41% for patients with high grade tumors ( p 5 0.01). Conclusion: Patients with low-grade tumors, especially those with myxopapillary subtypes, have high 5-year survival rates when treated with post-operative radiotherapy. High grade ependymomas are associated with a much poorer outcome. New forms of therapy are required to improve the outcome of patients with high-grade ependymomas. © 1998 Elsevier Science Inc.

Ependymoma, Surgery, Radiation therapy, Chemotherapy introduction.

INTRODUCTION

(3). Myxopapillary ependymomas are low-grade tumors found in the cauda equina region, where most arise from the filum terminale. The most characteristic histologic feature of myxopapillary tumors is the abundance of intercellular and perivascular mucin. Cytogenetic studies indicate that ependymomas frequently show abnormalities occurring on chromosome 9, 11, or 22 (4). Treatment usually includes maximal resection followed by radiotherapy. Chemotherapy is usually reserved for re- current tumors. However, recent clinical trials in children with high-grade tumors include chemotherapy as a compo- nent of initial therapy with surgery and radiation. (5, 6) The present analysis was undertaken to define the long- term outcome of patients with ependymomas. Treatment options and prognostic factors were evaluated to clarify their relationship to survival and disease control. These factors are evaluated to provide treatment recommendations and explore avenues of further research.

Ependymomas arise from ependymal cells forming the lin- ing of the ventricles and central canal of the spinal cord. It is estimated that 17,600 primary central nervous system (CNS) tumors were diagnosed in the United States during 1997 (1). Ependymomas represented 40–60% of the 2,700 primary spinal cord tumors and 1–8% of the 14,900 primary brain tumors (2). Intracranial ependymomas occur primarily in children and spinal ependymomas are more common in adults. In general, grading of ependymomas has been based upon a number of characteristics including cellularity, cytologic atypia, mitotic activity, vascular proliferation, and necrosis. These tumors are graded based primarily on mitotic activity and endothelial proliferation. Low-grade ependymomas are more common than high-grade tumors. The various histo- logic subtypes include classic, papillary, clear cell, ta- nycytic, pigmented (melanotic), and myxopapillary forms

Reprint requests to: Steven E. Schild, M.D., Mayo Clinic, De- partment of Radiation Oncology, 13400 E. Shea Boulevard,

Scottsdale, AZ 85259. E-mail: sschild@mayo.edu Accepted for publication 30 July 1998.

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