Maintenance Chemotherapy or Observation Following Induction Chemotherapy and Radiation Therapy in Treating Patients With Newly Diagnosed Ependymoma

PRIMARY OBJECTIVE: I. To determine the event free survival (EFS) and overall survival (OS) of children with completely resected ependymoma treated with post-operative conformal radiation therapy (cRT) and then randomized to receive or not receive four cycles of post radiation maintenance chemotherapy (vincristine, cisplatin, etoposide and cyclophosphamide \[VCEC\]). EXPLORATORY OBJECTIVES: I. To estimate the EFS and OS of children with incompletely resected ependymoma who are unable to achieve a complete response (CR) by post-operative induction chemotherapy or by second surgery who will then be non-randomly assigned to cRT followed by four cycles of maintenance chemotherapy (VCEC). II. To further evaluate the EFS and OS of children with supratentorial classic ependymoma who achieve a complete resection at first or second resection OR children who achieve a CR to short course induction chemotherapy following first surgery. III. To evaluate whether the addition of maintenance chemotherapy post-radiation therapy contributes to neurobehavioral morbidity and reduced functional outcomes over time, compared to patients treated with radiation therapy followed by observation alone. IV. To examine differences in neurobehavioral outcomes and quality of life of children treated with proton beam radiation therapy compared to children treated with conventional radiation delivery techniques. V. To evaluate biologic prognostic factors in childhood ependymoma by studying molecular groups as defined by deoxyribonucleic acid (DNA) methylation profiling and immunohistochemistry, copy number variants to identify 1q gain in posterior fossa ependymomas, CDKN2A loss (homozygous deletion) in supratentorial ependymomas and specific genetic alterations such as RELA fusions, YAP1 fusions and the H3 K27M mutation on initial tumor samples and correlating these data with clinical outcome. Va. To explore prognostic molecular signatures and genomic alterations in ependymomas by building upon the data derived from ACNS0121 to correlate biomarkers listed above with World Health Organization (WHO) grade, location, extent of resection, treatment, EFS and OS. OUTLINE: This is a multicenter study partially randomized phase III study. Patients are randomized or non-randomly treated according to tumor location and extent of surgical resection or post-surgery induction chemotherapy response. Arm I: Patients with classic histology(WHO Grade II) supratentorial ependymoma who have undergone microscopic gross total resection (GTR1) or achieved CR either after first or second resection or after post-operative induction chemotherapy are assigned to observation. For patients without GTR1, induction chemotherapy is comprised of vincristine intravenously (IV) over 1 minute on days 1 and 8 of cycles 1 and 2, carboplatin IV over 15-60 minutes on day 1 of cycles 1 and 2, and cyclophosphamide IV over 30-60 minutes on days 1-2 of cycle 1 only. Patients also receive etoposide IV over 60-120 minutes on days 1-3 of cycle 2 only. Cycle 1 continues for 3 weeks and cycle 2 continues for 4 weeks in the absence of disease progression or unacceptable toxicity. ARM II: Patients with supratentorial ependymoma (Grade II without GTR1 or Grade III) or any infratentorial ependymoma who have undergone gross or near total resection (GTR or NTR) or achieved CR either after first or second resection or after post-operative induction chemotherapy are randomized to undergo conformal radiotherapy over 6-7 weeks followed by maintenance chemotherapy. Maintenance chemotherapy comprised of vincristine IV on days 1, 8, and 15 of cycles 1-3 only, etoposide IV over 60-120 minutes on days 1-3, cisplatin IV over 1-8 hours on day 1, and cyclophosphamide IV over 30-60 minutes on days 2-3. Treatment repeats every 21 days for 4 courses in the absence of disease progression or unacceptable toxicity. Patients without GTR or NTR at enrollment require induction chemotherapy (see Arm I) and possibly second surgery before randomization. ARM III: Patients with supratentorial ependymoma (Grade II without GTR1 or ST Grade III) or any infratentorial ependymoma (Grade II or III) who have undergone gross or near total resection or achieved CR either after first or second resection or after post-operative induction chemotherapy are randomized to undergo conformal radiotherapy over 6-7 weeks and then undergo observation. Patients without GTR or NTR at enrollment require induction chemotherapy (see Arm I) and possibly second surgery before randomization. ARM IV: Patients with subtotal resection after induction chemotherapy (see Arm I) and second surgery are non-randomly assigned to Arm II treatment. After completion of study therapy, patients are followed up every 4 months for 5 years, and then annually thereafter.