Childhood Cerebellar Astrocytoma

Summary Type: Treatment
Summary Audience: Health professionals
Summary Language: English
Summary Description: Expert-reviewed information summary about the treatment of childhood cerebellar astrocytoma.

Childhood Cerebellar Astrocytoma

General Information

This cancer treatment information summary provides an overview of the diagnosis, classification, treatment, and prognosis of childhood cerebellar astrocytomas.

The National Cancer Institute provides the PDQ pediatric cancer treatment information summaries as a public service to increase the availability of evidence-based cancer information to health professionals, patients, and the public. These summaries are updated regularly according to the latest published research findings by an Editorial Board of 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 are increasingly used in tumor diagnosis and classification.

The classification of childhood brain tumors is based not only on histology, but also on location. Tumors are classically categorized as being infratentorial, sellar or suprasellar, or cortical based. Common infratentorial (posterior fossa) tumors include the following:

1. Cerebellar astrocytomas (usually pilocytic but also fibrillary and, less frequently, high-grade).
2. Medulloblastomas (primitive neuroectodermal tumors [PNET] ).
3. Ependymomas (cellular, papillary, clear cell, tanycytic, or anaplastic).
4. Brain stem gliomas are typically diffuse intrinsic high-grade tumors that are diagnosed neuroradiographically without biopsy. Focal, tectal, and exophytic cervicomedullary tumors are generally low-grade tumors.
5. Atypical teratoid/rhabdoid tumors (AT/RT).

Tumors that occur supratentorially include the following:

1. Low-grade cerebral hemispheric astrocytomas (grade 1 [pilocytic] or grade 2).
2. High-grade or malignant astrocytomas (anaplastic astrocytomas, glioblastoma multiforme [grade 3 or grade 4]).
3. Mixed gliomas (low-grade or high-grade).
4. Oligodendrogliomas (low-grade or high-grade).
5. Primitive neuroectodermal tumors (including cerebral neuroblastomas, pineoblastomas, ependymoblastomas).
6. AT/RT.
7. Ependymomas (cellular or anaplastic).
8. Meningiomas.
9. Choroid plexus tumors (papillomas and carcinomas).
10. Pineal parenchymal tumors (pineocytomas, or mixed pineal parenchymal tumors).
11. Neuronal and mixed neuronal glial tumors (gangliogliomas, desmoplastic infantile gangliogliomas, dysembryoplastic neuroepithelial tumors).
12. Metastasis (rare) from extraneural malignancies.

In addition to those tumors that occur supratentorially, other tumors that most commonly occur in the sellar or suprasellar region are:

1. Craniopharyngiomas.
2. Diencephalic astrocytomas (central tumors involving the chiasm, hypothalamus, and/or thalamus) that are generally low-grade (including astrocytomas, grade 1 [pilocytic] or grade 2).
3. Germ cell tumors (germinomas and nongerminomatous).

Important general concepts that should be understood by those caring for a child who has a brain tumor include the following:

1. Selection of an appropriate therapy can only occur if the correct diagnosis is made and the stage of the disease is accurately determined.
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, neuropathology, radiation oncology, pediatric oncology, neuro-oncology, neurology, rehabilitation, neuroradiology, endocrinology, and psychology, who have special expertise in the care of patients with these diseases.^1,2,3,
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 before therapy is begun.
4. For most 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.
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.^4,
6. The cause of most childhood brain tumors remains unknown.^5,6,

This summary discusses the treatment of childhood cerebellar astrocytoma.

Information about ongoing clinical trials is available from the NCI Web site.

¹ Strother DR, Poplack IF, Fisher PG, et al.: Tumors of the central nervous system. In: Pizzo PA, Poplack DG, eds.: Principles and Practice of Pediatric Oncology. 4th ed. Philadelphia, Pa: Lippincott, Williams and Wilkins, 2002, pp 751-824.

² Pollack IF: Brain tumors in children. N Engl J Med 331 (22): 1500-7, 1994.

³ Cohen ME, Duffner PK, eds.: Brain Tumors in Children: Principles of Diagnosis and Treatment. 2nd ed. New York: Raven Press, 1994.

⁴ Guidelines for the pediatric cancer center and role of such centers in diagnosis and treatment. American Academy of Pediatrics Section Statement Section on Hematology/Oncology. Pediatrics 99 (1): 139-41, 1997.

⁵ Kuijten RR, Bunin GR: Risk factors for childhood brain tumors. Cancer Epidemiol Biomarkers Prev 2 (3): 277-88, 1993 May-Jun.

⁶ Kuijten RR, Strom SS, Rorke LB, et al.: Family history of cancer and seizures in young children with brain tumors: a report from the Childrens Cancer Group (United States and Canada). Cancer Causes Control 4 (5): 455-64, 1993.

Cellular Classification

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. Most of the remainder will be diffuse or fibrillary astrocytomas. Malignant gliomas are rare.¹ 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 2 distinct groups: pilocytic or Gilles type A tumors and diffuse or Gilles type B tumors; the latter tumors have a poor prognosis.² Expert neuropathologic review is important.

¹ Kleihues P, Cavenee WK, eds.: Pathology and Genetics of Tumours of the Nervous System. Lyon, France: International Agency for Research on Cancer, 2000.

² Gilles FH, Sobel EL, Tavaré CJ, et al.: Age-related changes in diagnoses, histological features, and survival in children with brain tumors: 1930-1979. The Childhood Brain Tumor Consortium. Neurosurgery 37 (6): 1056-68, 1995.

Stage Information

In general, tumors are separated into either cerebellar hemisphere or more diffuse, midline lesions.^1,

¹ Hayostek CJ, Shaw EG, Scheithauer B, et al.: Astrocytomas of the cerebellum. A comparative clinicopathologic study of pilocytic and diffuse astrocytomas. Cancer 72 (3): 856-69, 1993.

Treatment Option Overview

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 2 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.

The designations in PDQ that treatments are “standard” or “under clinical evaluation” are not to be used as a basis for reimbursement determinations.

Untreated Childhood Cerebellar Astrocytoma

Surgical resection is the primary treatment for childhood cerebellar astrocytoma.^1,2,3 Complete or near complete removal can be obtained in 90% to 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.^3,4 Following resection, a postoperative MRI is obtained. Surveillance scans are then obtained periodically for totally resected tumors, although the value of this is uncertain.⁵ The optimal use of radiation therapy is the subject of controversy. Treatment is often withheld in patients with residual disease until tumor progression has been documented.⁶ Chemotherapy may be useful for delaying radiation therapy in the very young child with unresectable, progressive cerebellar astrocytoma.^7,

¹ Campbell JW, Pollack IF: Cerebellar astrocytomas in children. J Neurooncol 28 (2-3): 223-31, 1996 May-Jun.

² Schneider JH Jr, Raffel C, McComb JG: Benign cerebellar astrocytomas of childhood. Neurosurgery 30 (1): 58-62; discussion 62-3, 1992.

³ Due-Tønnessen BJ, Helseth E, Scheie D, et al.: Long-term outcome after resection of benign cerebellar astrocytomas in children and young adults (0-19 years): report of 110 consecutive cases. Pediatr Neurosurg 37 (2): 71-80, 2002.

⁴ Hayostek CJ, Shaw EG, Scheithauer B, et al.: Astrocytomas of the cerebellum. A comparative clinicopathologic study of pilocytic and diffuse astrocytomas. Cancer 72 (3): 856-69, 1993.

⁵ Sutton LN, Cnaan A, Klatt L, et al.: Postoperative surveillance imaging in children with cerebellar astrocytomas. J Neurosurg 84 (5): 721-5, 1996.

⁶ Garcia DM, Marks JE, Latifi HR, et al.: Childhood cerebellar astrocytomas: is there a role for postoperative irradiation? Int J Radiat Oncol Biol Phys 18 (4): 815-8, 1990.

⁷ Packer RJ, Lange B, Ater J, et al.: Carboplatin and vincristine for recurrent and newly diagnosed low-grade gliomas of childhood. J Clin Oncol 11 (5): 850-6, 1993.

Recurrent Childhood 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 patients. 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.

Patients with cerebellar astrocytoma (pilocytic or diffuse) who relapse after being treated with surgery alone should be considered for another surgical resection.¹ If this is not feasible, local radiation therapy is the usual treatment.² If there is recurrence in an unresectable site after irradiation, chemotherapy should be considered.² 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.

¹ Austin EJ, Alvord EC Jr: Recurrences of cerebellar astrocytomas: a violation of Collins' law. J Neurosurg 68 (1): 41-7, 1988.

² Garcia DM, Marks JE, Latifi HR, et al.: Childhood cerebellar astrocytomas: is there a role for postoperative irradiation? Int J Radiat Oncol Biol Phys 18 (4): 815-8, 1990.

Changes to This Summary (07/22/2005)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

General Information

Added text to describe the classification of childhood brain tumors.

Added text to state that brain stem gliomas are typically diffuse intrinsic high-grade tumors that are diagnosed neuroradiographically without biopsy. Focal, tectal, and exophytic cervicomedullary tumors are generally low-grade tumors.

Added text to include a typical teratoid/rhabdoid tumors as tumors that occur supratentorially.

Added text to include tumors that commonly occur in the sellar or suprasellar region: craniopharyngiomas, diencephalic astrocytomas, and germ cell tumors.

Cellular Classification

Added Gilles et al. as reference 2.

Stage Information

Revised text to state that, in general, tumors are separated into either cerebellar hemisphere or more diffuse, midline lesions (cited Hayostek et al.).

Untreated Childhood Cerebellar Astrocytoma

Added Due-Tønnessen et al. as reference 3.

Added text to state that treatment is often withheld in patients with residual disease until tumor progression has been documented (cited Garcia et al.).

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