Ependymomas in children.

Ependymomas originate throughout the central nervous system (CNS), representing 10-12% of CNS tumors in children. The majority occur in children less than 5 years of age. Tumors occur most often in the 4th ventricular region. Current controversies regarding ependymomas include histologic categorization or 'differentiation'. It is estimated that approximately 25% of childhood tumors are appropriately categorized as anaplastic or 'high-grade' lesions. Surgical resection is curative for tumors originating in the cauda equina; recent data suggest that surgery alone has achieved disease control in 75% of intramedullary tumors. For intracranial ependymomas, postoperative irradiation has been shown to improve survival in series dating from the 1960-1980 era. Debate regarding the necessary volume for radiation therapy (i.e. local treatment or craniospinal irradiation) centers on the reported rate of neuraxis seeding. An overall incidence of 12% has been documented in the literature, with clinico-histologic correlation suggesting that anaplastic or high-grade infratentorial ependymomas are associated with the highest frequency of subarachnoid spread. Recent reports of chemotherapy show response to several single agents, with no clear documentation that adjuvant chemotherapy has improved survival to date. Current studies utilizing preirradiation chemotherapy address tumor response and ultimate control in a sequence of surgery, chemotherapy, and irradiation primarily in very young children or those with anaplastic or high-grade tumors.