Preradiation chemotherapy in primary high-risk brainstem tumors: Phase II study CCG-9941 of the children's cancer group

Purpose: This Children's Cancer Group group-wide phase II trial evaluated the efficacy and toxicity of two chemotherapy arms administered before hyperfractionated external-beam radiotherapy (HFEBRT). Patients and Methods: Thirty-two patients with newly diagnosed brainstem gliomas were randomly assigned to regimen A and 31 to regimen B. Regimen A comprised three courses of carboplatin, etoposide, and vincristine; regimen B comprised cisplatin, etoposide, cyclophosphamide, and vincristine. Both arms included granulocyte colony-stimulating factor. Patients were evaluated by magnetic resonance imaging after induction chemotherapy and HFEBRT at a dose of 72 Gy. Results: Ten percent ± 5% of regimen A patients objectively responded to chemotherapy. For combined induction and radiotherapy, 27% ± 9% of patients improved. The neuroradiographic response rate for regimen B was 19% ± 8% for chemotherapy and 23% ± 9% after HFEBRT. Response rates were not statistically significant between regimens after induction or chemotherapy/HFEBRT. Event-free survival was 17% ± 5% (estimate ± SE) at 1 year and 6% ± 3% at 2 years. Survival was significantly longer among patients who responded to chemotherapy (P < .05). Among patients who received regimen A induction, grades 3 and 4 leukopenia were observed in 50% to 65%, with one toxicity-related death. For regimen B, severe leukopenia occurred in 86% to 100%, with febrile neutropenia in 48% to 60% per course. Conclusion: Neither chemotherapy regimen meaningfully improved response rate, event-free survival, or overall survival relative to previous series of patients with brainstem gliomas who received radiotherapy with or without chemotherapy.