Observing Young Patients With Ependymoma Undergoing Standard Combination Chemotherapy

DISEASE CHARACTERISTICS: * Histologically confirmed WHO grade 3 anaplastic (malignant) ependymoma or WHO grade 2 ependymoma, including the following variants: * Papillary * Cellular * Clear cell * Tanycytic * No myxopapillary ependymoma, subependymoma, or ependymoblastoma * Meets 1 of the following criteria: * Has undergone complete resection of the primary tumor (prior to starting chemotherapy) * Two or more surgical procedures to achieve complete resection allowed * Metastatic disease at diagnosis (with or without complete resection of the primary tumor) * Unable to undergo complete resection of the primary tumor (with or without metastatic disease) * Patients with measurable residual disease (primary or metastatic disease) are eligible provided they undergo treatment on clinical trial CCLG-CNS-2005-03 prior to entering this study * Has undergone surgical resection OR completed treatment on clinical trial CCLG-CNS-2005-03 within the past 3 weeks * Patients who are unable to tolerate chemotherapy or who do not receive treatment according to the CCLG guidelines for ependymoma due to parental preference or recommendation from the treating physician are eligible PATIENT CHARACTERISTICS: * Able to tolerate IV hydration * No active infection PRIOR CONCURRENT THERAPY: * See Disease Characteristics