Efficacy of temozolomide for recurrent embryonal brain tumors in children

Objective: The salvage therapy of recurrent embryonal brain tumors in children is disappointing. Temozolomide is a newly developed chemotherapeutic agent in central nervous system tumors. This study analyzed the efficacy of temozolomide on the treatment of recurrent embryonal brain tumors in children. Materials and methods: There were eight patients, including four with medulloblastoma (MB), three with atypical teratoid/rhabdoid tumor (AT/RT) and one with supratentorial primitive neuroectodermal tumor, whose tumors recurred after surgery and radiotherapy, with or without conventional intravenous cisplastin-based chemotherapy. They all received once daily oral temozolomide (150 mg/m²/day) for five consecutive days in a 28-day cycle. The responsiveness of the tumors to temozolomide was judged by magnetic resonance imaging (MRI) during regular follow-up. Results: The median treatment cycles received by these eight patients were 17 (range from two to 59 cycles). The follow-up MRI showed no tumor progression in five patients at 6 months and four patients at 12 months. The median progression-free survival (PFS) of the eight patients was 15.7 months (range from 0 to 59 months). Complete response was achieved in one patient with MB accompanying with a long period of PFS for 26 months. Another patient with AT/RT showed partial response accompanying with a long period of PFS for 59 months. The observed adverse effects of temozolomide included nausea, vomiting, headache, constipation, mild marrow suppression, and decreased activity; none of them was severe enough to discontinue the treatment. No patient experienced moderate or severe marrow suppression in this series. Conclusion: In this preliminary study, oral temozolomide shows promising results on recurrent embryonal brain tumors in children. The adverse effects of temozolomide are mild and tolerable. When conventional chemotherapy fails and/or the adverse response is too severe to tolerate, temozolomide is a reasonable alternative. However, a further well-designed, controlled study and more long-term follow-up are needed to assess the exact role of temozolomide in children with embryonal tumors in brain.