A Study of Lower Radiotherapy Dose to Treat Children With CNS Germinoma

PRIMARY OBJECTIVE: I. To determine whether 12 Gy whole ventricular irradiation (WVI) and 12 Gy tumor boost would maintain similar efficacy compared to ACNS1123 stratum 2 as measured by event-free survival (EFS) in eligible patients with localized primary central nervous system (CNS) germinoma who present with serum and/or cerebrospinal fluid (CSF) human chorionic gonadotropin-beta (hCGbeta) ≤ 100 IU/L and normal alpha-fetoprotein (AFP), and meet complete response (CR) or continued complete response (CCR) criteria following chemotherapy/second-look surgery (Stratum 1). SECONDARY OBJECTIVES: I. To estimate the EFS distribution for patients with localized midline - including bifocal - CNS germinoma with partial response (PR) after chemotherapy, followed by 18 Gy WVI and 12 Gy tumor boost (Stratum 2). II. To estimate the EFS distribution for patients with localized midline - including bifocal - CNS germinoma with less than a PR after chemotherapy, followed by 24 Gy WVI and 12 Gy tumor boost (Stratum 3). III. To estimate the overall survival (OS), response rates to chemotherapy and radiotherapy (RT), as well as the patterns of failure of the various cohorts based on tumor characteristics, treatment regimen, and treatment modality. IV. To determine the impact of tumor characteristics, treatment regimen and treatment modalities on the long-term neuroendocrine function for patients with CNS germinomas. V. To prospectively evaluate processing speed of children and young adults with CNS germinoma through the Children's Oncology Group (COG) Standardized assessment battery. EXPLORATORY OBJECTIVES: I. To estimate the EFS distribution for patients with metastatic germinomas treated with chemotherapy followed by craniospinal irradiation (CSI) \[18 Gy for CR/CCR (Stratum 4)\] or \[24 Gy for less than CR (Stratum 5)\] with a 12 Gy tumor boost to the pre-treatment volume, including metastatic sites. II. To estimate the EFS distribution for patients with basal ganglia and thalamic germinomas (BGTG) treated with chemotherapy followed by whole brain irradiation (WBI) \[18 Gy for CR/CCR (Stratum 6)\] or \[24 Gy for less than CR (Stratum 7)\] with a 12 Gy tumor boost to the pre-treatment volume. III. To prospectively collect blood, cerebrospinal fluid, and tumor tissue at diagnosis and second-look surgery (if feasible) for future biology studies. IV. To prospectively measure the incidence of cerebral vascular events (stroke or transient ischemic attacks) in the follow-up period and longitudinally evaluate and model the cognitive, social and behavioral functioning of children and young adults with CNS germinoma through the COG Standardized assessment battery, and compare these outcomes based on tumor characteristics, treatment regimen, and treatment modality. OUTLINE: INDUCTION PHASE: All patients receive carboplatin intravenously (IV) over 15-60 minutes on day 1 and etoposide IV over 90-120 minutes on days 1-3 of each cycle. Treatment repeats every 21 days for up to 4 cycles in the absence of disease progression or unacceptable toxicity. Patients are then assigned to 1 of 7 strata. STRATUM I: Patients with localized germinoma achieving CR with normalization of markers undergo 3-dimensional conformal radiation therapy (3D-CRT)/3-dimensional conformal proton radiation therapy (3D-CPRT) or intensity-modulated radiation therapy (IMRT)/intensity modulated proton therapy (IMPT) once daily (QD) 5 days a week for 16 days. Patients achieving PR with normalization of markers may undergo second-look surgery. Patients found to have mature teratoma or non-viable tumor undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 16 days. Patients with normalization of markers who fail to achieve CR or PR may undergo second-look surgery. Patients found to have mature teratoma or non-viable tumor undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 16 days. Patients with bifocal germinoma undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 16 days. STRATUM II: Patients with localized germinoma achieving PR with normalization of markers who do not undergo second-look surgery undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 20 days. STRATUM III: Patients with localized germinoma with normalization of markers who fail to achieve CR or PR who do not undergo second-look surgery undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 24 days. STRATUM IV: Patients with metastatic germinoma achieving CR undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 20 days. Patients with metastatic germinoma and normalization of markers who fail to achieve CR may undergo second-look surgery. Patients found to have mature teratoma or non-viable tumor undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 20 days. STRATUM V: Patients with metastatic germinoma with normalization of markers who fail to achieve CR who do not undergo second-look surgery undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 24 days. STRATUM VI: Patients with basal ganglia and thalamic germinoma achieving CR undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 20 days. Patients with basal ganglia and thalamic germinoma and normalization of markers who fail to achieve CR may undergo second-look surgery. Patients found to have mature teratoma or non-viable tumor undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 20 days. STRATUM VII: Patients with basal ganglia and thalamic germinoma with normalization of markers who fail to achieve CR who do not undergo second-look surgery undergo 3D-CRT/3D-CPRT or IMRT/IMPT QD 5 days a week for 24 days. Patients with non-normalized tumor markers or PD and no second-look surgery or viable tumor during second-look surgery discontinue protocol therapy. All patients undergo magnetic resonance imaging (MRI) and optional blood and tissue sample collection throughout the study. Patients may undergo lumbar puncture (LP) for CSF sample collection during screening and follow up. After completion of study treatment, patients are followed up every 3 months for 12 months, every 4 months for 24 months, and then annually for up to 120 months.