PDQ® Treatment Health Professionals
This treatment information summary on childhood cerebellar astrocytoma is an overview of diagnosis, classification, patient treatment, and prognosis. The National Cancer Institute created the PDQ database to increase the availability of new treatment information and its use in treating patients. Information and references from the most recently published literature are included after review by pediatric oncology specialists.
Primary brain tumors are a diverse group of diseases that together constitute the most common solid tumor of childhood. Brain tumors are classified according to histology, but tumor location and extent of spread are important factors that affect treatment and prognosis. Immunohistochemical analysis, cytogenetic and molecular genetic findings, and measures of mitotic activity have been used in tumor diagnosis and classification.
Approximately 50% of brain tumors in children are infratentorial, with three fourths of these located in the cerebellum or fourth ventricle. Common infratentorial (posterior fossa) tumors include the following:
2. medulloblastoma (primitive neuroectodermal tumor)
4. brain stem glioma (often diagnosed neuroradiographically without biopsy; may be high- or low-grade)
2. diencephalic (chiasm, hypothalamic, and/or thalamic) gliomas generally of low grade
2. high-grade or malignant astrocytoma (anaplastic astrocytoma, glioblastomas multiforme (grade 3 or grade 4))
3. mixed glioma
5. primitive neuroectodermal tumor (cerebral neuroblastoma)
8. choroid plexus tumors (papilloma and carcinoma)
9. pineal parenchymal tumors (pineoblastoma, pineocytoma, or mixed pineal parenchymal tumor)
10. neuronal and mixed neuronal glial tumor (ganglioglioma, desmoplastic infantile ganglioglioma, dysembryoplastic neuroepithelial tumor)
2. Children with primary brain tumors represent a major therapy challenge that, for optimal results, requires the coordinated efforts of pediatric specialists in fields such as neurosurgery, neurology, rehabilitation, neuropathology, radiation oncology, medical oncology, neuroradiology, endocrinology, and psychology, who have special expertise in the care of patients with these diseases.[1-3]
3. More than one half of children diagnosed with brain tumors will survive 5 years from diagnosis. In some subgroups of patients, an even higher rate of survival and cure is possible. Each child's treatment should be approached with curative intent, and the possible long-term sequelae of the disease and its treatment should be considered when therapy is begun.
4. For the majority of childhood brain tumors, the optimal treatment regimen has not been determined. Children who have brain tumors should be considered for enrollment in a clinical trial when an appropriate study is available. Such clinical trials are being carried out by institutions and cooperative groups. In the United States, the two major cooperative groups are the Pediatric Oncology Group and the Childrens Cancer Group.
5. Guidelines for pediatric cancer centers and their role in the treatment of pediatric patients with cancer have been outlined by the American Academy of Pediatrics.
For information on current clinical trials for children with brain tumors, consult the PDQ Protocol File. References:
The classification of brain tumors is based on both histopathologic characteristics and location in the brain. More than 80% of all childhood cerebellar gliomas will be pilocytic astrocytomas, which are also considered to be grade 1 astrocytomas. The majority of the remainder will be diffuse or fibrillary astrocytomas. Malignant gliomas are rare. The pathologic classification of pediatric brain tumors is a specialized area that is undergoing evolution; review of the diagnostic tissue by a neuropathologist who has particular expertise in this area is strongly recommended.
These generally low-grade, often cystic astrocytic tumors are localized to the cerebellum. Except for malignant gliomas, contiguous spread or metastasis outside that region is extremely rare. The presence of certain histologic features has been used retrospectively to stratify cerebellar astrocytomas into two distinct groups: pilocytic or Gilles type A tumors and diffuse or Gilles type B tumors; the latter tumors have a poor prognosis. Expert neuropathologic review is important.
For information on the histologic features of cerebellar astrocytoma, refer to the cellular classification section of this summary. There is no accepted staging for childhood cerebellar astrocytomas.
Many of the improvements in survival in childhood cancer have been made as a result of clinical trials that have attempted to improve on the best available, accepted therapy. Clinical trials in pediatrics are designed to compare new therapy with therapy that is currently accepted as standard. This comparison may be done in a randomized study of two treatment arms or by evaluating a single new treatment and comparing the results with those that were previously obtained with existing therapy.
Because of the relative rarity of cancer in children, all patients with brain tumors should be considered for entry into a clinical trial. To determine and implement optimum treatment, treatment planning by a multidisciplinary team of cancer specialists who have experience treating childhood brain tumors is required. Radiation therapy of pediatric brain tumors is technically very demanding and should be carried out in centers that have experience in that area in order to ensure optimal results.
Debilitating effects on growth and neurologic development have frequently been observed following radiation therapy, especially in younger children.[1-3] For this reason, the role of chemotherapy in allowing a delay in the administration of radiation therapy is under study, and preliminary results suggest that chemotherapy can be used to delay, and sometimes obviate, the need for radiation therapy in children with benign and malignant lesions. Long-term management of these patients is complex and requires a multidisciplinary approach.
The designations in PDQ that treatments are "standard" or "under clinical evaluation" are not to be used as a basis for reimbursement determinations.
Surgical resection is the primary treatment for childhood cerebellar astrocytoma.[1,2] Complete or near complete removal can be obtained in 90%-95% of patients with juvenile pilocytic tumors. Diffuse cerebellar astrocytomas may be less amenable to total resection, and this may account for the poorer outcome. The extent of resection necessary for cure is unknown because patients with microscopic and even gross residual tumor after surgery may experience long-term progression-free survival without postoperative therapy. The optimal use of radiation therapy is the subject of controversy. Some radiation oncologists advocate the treatment of patients with residual disease, and others withhold treatment until tumor progression has been documented. Chemotherapy may be useful for delaying radiation therapy in the very young child with unresectable, progressive cerebellar astrocytoma.
Recurrence may take place in childhood cerebellar gliomas and may develop many years after initial treatment. Disease can be at the primary tumor site or, especially in malignant tumors, at noncontiguous central nervous system sites. Systemic relapse is rare, but may occur. At the time of recurrence, a complete evaluation to determine the extent of relapse is indicated for all malignant tumors and, at times, for more benign lesions. Biopsy or surgical resection may be necessary for confirmation of relapse because other entities such as secondary tumor and treatment-related brain necrosis may be clinically indistinguishable from tumor recurrence. The need for surgical intervention must be individualized on the basis of the initial tumor type, the length of time between initial treatment and the reappearance of the mass lesion, and the clinical picture.
Cerebellar pilocytic astrocytomas are treated initially with surgery alone; diffuse cerebellar astrocytomas are treated with surgery and radiation therapy administered either initially for postsurgical residual disease or at the time of disease progression. Patients with cerebellar astrocytoma (pilocytic or diffuse) who relapse after being treated with surgery alone should be considered for another surgical resection. If this is not feasible, local radiation therapy is the usual treatment. If there is recurrence in an unresectable site after irradiation, chemotherapy should be considered. There is little information regarding the activity of chemotherapy in this disease. Studies of novel therapeutic approaches that are designed to test the activity and toxicity of chemotherapy in recurrent brain tumor patients should be considered.
Date Last Modified: 08/1999