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Pediatric glial tumors
K J Cohen1, A Broniscer, J Glod
1Pediatric Oncology, Johns Hopkins Oncology Center, CMSC-800, 600 N. Wolfe Street, Baltimore, MD 21287, USA. kcohen@jhmi.edu
Insights
Pediatric glial neoplasms differ from adult types, with infratentorial tumors predominating. Maximal surgical resection is key for pilocytic astrocytomas and ependymomas, while radiation and chemotherapy play evolving roles.
Area of Science:
- Pediatric neuro-oncology
- Pediatric glial neoplasms
- Pediatric brain tumors
Background:
- Pediatric glial neoplasms are heterogeneous, differing significantly from adult gliomas in histology and location.
- Infratentorial tumors, including posterior fossa and brain stem gliomas, are more common in children than adults.
Purpose of the Study:
- To review the characteristics and treatment strategies for three common pediatric glial tumors: diffuse intrinsic pontine gliomas, pilocytic astrocytomas, and ependymomas.
- To highlight the differences in therapeutic approaches based on tumor type and patient age.
Main Methods:
- Review of current therapeutic strategies including maximal surgical resection, radiation therapy, and chemotherapy.
- Discussion of the role and efficacy of each treatment modality for specific pediatric glial tumor types.
Main Results:
- Maximal surgical resection is the primary treatment for pilocytic astrocytomas and ependymomas, crucial for favorable outcomes.
- Radiation therapy is standard for ependymomas and used for pontine gliomas to slow progression; its role in pilocytic astrocytomas is for specific cases.
- Chemotherapy's role is evolving, showing efficacy in young children with pilocytic astrocytomas and ependymomas, but not curative for diffuse intrinsic pontine gliomas.
Conclusions:
- Treatment of pediatric glial neoplasms requires tailored approaches based on histology and location.
- While surgery and radiation are mainstays for some tumors, chemotherapy offers a vital alternative, especially in young children.
- Diffuse intrinsic pontine gliomas remain uniformly lethal despite current therapeutic advancements.
Abstract:
Glial neoplasms in children comprise many heterogeneous tumors that include pilocytic and fibrillary astrocytomas, ependymomas, and the diffuse intrinsic pontine gliomas. In contrast to adults, most of whom present with high-grade fibrillary neoplasms, alternate histologies represent most cases seen in the pediatric setting. In addition, although most adult gliomas are supratentorial in location, in pediatrics infratentorial tumors (posterior fossa and brain stem) predominate. We discuss three specific tumors: diffuse intrinsic pontine gliomas; pilocytic astrocytomas; and ependymomas. Maximal surgical resection is the mainstay of therapy for both pilocytic astrocytomas and ependymomas. Failure to achieve an optimal resection often results in progression and the need for further therapy for patients with pilocytic astrocytomas, and is ultimately fatal in most children with subtotally resected ependymomas. Surgical resection has no role in the treatment of pontine gliomas. Focal radiation therapy is included routinely in the treatment of ependymomas, and it has been shown to improve event-free survival. This therapy also is used in the treatment of pontine gliomas because radiation treatment appears to slow inevitable tumor progression. Radiation therapy in pilocytic astrocytomas is generally reserved for patients who progress after an initial surgical resection or for those patients with midline tumors; these patients are poor candidates for aggressive surgical resection. The role of chemotherapy in these tumors is in evolution. Chemotherapy for pilocytic astrocytomas, particularly in young children (for whom radiation therapy is avoided), appears to be effective in the treatment of a subset of patients. Up-front chemotherapy is generally reserved for the youngest children who present with ependymoma. In the recurrence setting, chemotherapy has shown some activity, although this approach is never curative. Despite the application of various chemotherapeutics and other biologic agents, none of these therapies has improved the prognosis for patients with the uniformly lethal pontine glioma.