Chemotherapy

The numerous chemotherapy treatment protocols for pediatric brain tumors reflect the extreme heterogeneity of these neoplasms. In the setting of average-risk medulloblastoma and germinoma, which have high cure rates with radiation treatment alone, chemotherapy is used to reduce radiation doses, yet maintain high cure rates. For infants with malignant brain tumors, who are particularly vulnerable to radiation-related morbidity, chemotherapy has been used to delay radiation treatment. Similarly, in the setting of unresectable, low-grade astrocytoma, chemotherapy can provide prolonged disease stabilization, perhaps allowing for delay of radiation.

While many clinical trials evaluating chemotherapy for the treatment of central nervous system (CNS) tumors are exploratory, two randomized controlled trials have shown a survival benefit from the addition of chemotherapy to radiation therapy in comparison to radiation therapy alone in children with brain tumors. Sposto et al. reporting for the Children's Cancer Group, described a randomization of patients with newly diagnosed high-grade glioma between two treatment arms: postoperative radiation treatment alone versus treatment with postoperative radiation followed by chemotherapy (Sposto et al. 1989). The chemotherapy group had 46% 5-year event-free survival (EFS), while the radiation-only group had 18% 5-year EFS. More recently, a large-scale, multiinstitutional European trial reported improved 5-year EFS with the addition of chemotherapy to radiation therapy for average-risk medulloblastoma (74% for radiation with chemotherapy vs. 59% for radiation alone) (Taylor et al. 2003).