Table of Contents
General Information
Cellular Classification
Stage Information
Treatment Option Overview
Untreated Childhood Cerebellar Astrocytoma
Recurrent Childhood Cerebellar Astrocytoma
General Information
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.
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:
1. cerebellar astrocytoma (usually pilocytic but also fibrillary and high-grade)
2. medulloblastoma (primitive neuroectodermal tumor)
3. ependymoma (low-grade or anaplastic)
4. brain stem glioma (often diagnosed neuroradiographically without biopsy; may be high-grade or low-grade)
5. atypical teratoid
Supratentorial tumors include those tumors that occur in the sellar or suprasellar region and/or other areas of the cerebrum. Sellar/suprasellar tumors comprise approximately 20% of childhood brain tumors and include the following:
1. craniopharyngioma
2. diencephalic (chiasm, hypothalamic, and/or thalamic) gliomas generally of low grade
3. germ cell tumors (germinoma and nongerminomatous)
Other tumors that occur supratentorially include the following:
1. low-grade astrocytoma or glioma (grade 1 or grade 2)
2. high-grade or malignant astrocytoma (anaplastic astrocytoma, glioblastomas multiforme (grade 3 or grade 4))
3. mixed glioma (low-grade or high-grade)
4. oligodendroglioma (low-grade or high-grade)
5. primitive neuroectodermal tumor (cerebral neuroblastoma)
6. ependymoma (low-grade or anaplastic)
7. meningioma
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)
11. metastasis (rare) from extra neural malignancies
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, 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 before 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.
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 the vast majority of childhood brain tumors remains unknown.5,6
References:
1. Heideman RL, Packer RJ, Albright LA, et al.: Tumors of the central nervous system. In: Pizzo PA, Poplack DG, eds.: Principles and Practice of Pediatric Oncology. Philadelphia, PA: Lippincott-Raven, 3rd ed., 1997, pp 633-697.
2. Pollack IF: Brain tumors in children. New England Journal of Medicine 331(22): 1500-1507, 1994.
3. Cohen ME, Duffman PK, eds: Brain Tumors in Children: Principles of Diagnosis and Treatment, 2nd ed. New York: Raven Press, 1994.
4. Sanders J, Glader B, Cairo M, et al.: 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): 139-141, 1997.
5. Kuijten RR, Bunin GR: Risk factors for childhood brain tumors. Cancer Epidemiology, Biomarkers and Prevention 2(3): 277-288, 1993.
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 and Control 4(5): 455-464, 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. The majority 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 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.
References:
1. Kleihues P, Cavenee WK, eds.: Pathology and Genetics of Tumours of the Nervous System. Lyon, France: International Agency for Research on Cancer, 2000.
Stage Information
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.
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 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.
Untreated Childhood Cerebellar Astrocytoma
Surgical resection is the primary treatment for childhood cerebellar astrocytoma.1,2 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. Following resection, a post-operative MRI is obtained. Surveillance scans are then obtained periodically for 5 years for totally resected tumors, although the value of this is uncertain.3 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.4
References:
1. Campbell JW, Pollack IF: Cerebellar astrocytomas in children. Journal of Neuro-Oncology 28(2-3): 223-231, 1996.
2. Schneider JH Jr, Raffel C, McComb JG: Benign cerebellar astrocytomas of childhood. Neurosurgery 30(1): 58-62; discussion 62-63, 1992.
3. Sutton LN, Cnaan A, Klatt L, et al.: Postoperative surveillance imaging in children with cerebellar astrocytomas. Journal of Neurosurgery 84(5): 721-725, 1996.
4. Packer RJ, Lange B, Ater J, et al.: Carboplatin and vincristine for recurrent and newly diagnosed low-grade gliomas of childhood. Journal of Clinical Oncology 11(5): 850-856, 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. 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.
References:
1. Austin EJ, Alvord EC: Recurrences of cerebellar astrocytomas: a violation of Collins' law. Journal of Neurosurgery 68(1): 41-47, 1988.
2. Packer RJ, Lange B, Ater J, et al.: Carboplatin and vincristine for recurrent and newly diagnosed low-grade gliomas of childhood. Journal of Clinical Oncology 11(5): 850-856, 1993.
Cellular Classification
Stage Information
Treatment Option Overview
Untreated Childhood Cerebellar Astrocytoma
Recurrent Childhood Cerebellar Astrocytoma
General Information
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.
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:
1. cerebellar astrocytoma (usually pilocytic but also fibrillary and high-grade)
2. medulloblastoma (primitive neuroectodermal tumor)
3. ependymoma (low-grade or anaplastic)
4. brain stem glioma (often diagnosed neuroradiographically without biopsy; may be high-grade or low-grade)
5. atypical teratoid
Supratentorial tumors include those tumors that occur in the sellar or suprasellar region and/or other areas of the cerebrum. Sellar/suprasellar tumors comprise approximately 20% of childhood brain tumors and include the following:
1. craniopharyngioma
2. diencephalic (chiasm, hypothalamic, and/or thalamic) gliomas generally of low grade
3. germ cell tumors (germinoma and nongerminomatous)
Other tumors that occur supratentorially include the following:
1. low-grade astrocytoma or glioma (grade 1 or grade 2)
2. high-grade or malignant astrocytoma (anaplastic astrocytoma, glioblastomas multiforme (grade 3 or grade 4))
3. mixed glioma (low-grade or high-grade)
4. oligodendroglioma (low-grade or high-grade)
5. primitive neuroectodermal tumor (cerebral neuroblastoma)
6. ependymoma (low-grade or anaplastic)
7. meningioma
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)
11. metastasis (rare) from extra neural malignancies
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, 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 before 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.
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 the vast majority of childhood brain tumors remains unknown.5,6
References:
1. Heideman RL, Packer RJ, Albright LA, et al.: Tumors of the central nervous system. In: Pizzo PA, Poplack DG, eds.: Principles and Practice of Pediatric Oncology. Philadelphia, PA: Lippincott-Raven, 3rd ed., 1997, pp 633-697.
2. Pollack IF: Brain tumors in children. New England Journal of Medicine 331(22): 1500-1507, 1994.
3. Cohen ME, Duffman PK, eds: Brain Tumors in Children: Principles of Diagnosis and Treatment, 2nd ed. New York: Raven Press, 1994.
4. Sanders J, Glader B, Cairo M, et al.: 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): 139-141, 1997.
5. Kuijten RR, Bunin GR: Risk factors for childhood brain tumors. Cancer Epidemiology, Biomarkers and Prevention 2(3): 277-288, 1993.
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 and Control 4(5): 455-464, 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. The majority 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 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.
References:
1. Kleihues P, Cavenee WK, eds.: Pathology and Genetics of Tumours of the Nervous System. Lyon, France: International Agency for Research on Cancer, 2000.
Stage Information
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.
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 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.
Untreated Childhood Cerebellar Astrocytoma
Surgical resection is the primary treatment for childhood cerebellar astrocytoma.1,2 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. Following resection, a post-operative MRI is obtained. Surveillance scans are then obtained periodically for 5 years for totally resected tumors, although the value of this is uncertain.3 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.4
References:
1. Campbell JW, Pollack IF: Cerebellar astrocytomas in children. Journal of Neuro-Oncology 28(2-3): 223-231, 1996.
2. Schneider JH Jr, Raffel C, McComb JG: Benign cerebellar astrocytomas of childhood. Neurosurgery 30(1): 58-62; discussion 62-63, 1992.
3. Sutton LN, Cnaan A, Klatt L, et al.: Postoperative surveillance imaging in children with cerebellar astrocytomas. Journal of Neurosurgery 84(5): 721-725, 1996.
4. Packer RJ, Lange B, Ater J, et al.: Carboplatin and vincristine for recurrent and newly diagnosed low-grade gliomas of childhood. Journal of Clinical Oncology 11(5): 850-856, 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. 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.
References:
1. Austin EJ, Alvord EC: Recurrences of cerebellar astrocytomas: a violation of Collins' law. Journal of Neurosurgery 68(1): 41-47, 1988.
2. Packer RJ, Lange B, Ater J, et al.: Carboplatin and vincristine for recurrent and newly diagnosed low-grade gliomas of childhood. Journal of Clinical Oncology 11(5): 850-856, 1993.
0 comments
Post a Comment