Central nervous system tumors account for about 20% of all childhood cancers. They are second in incidence, only surpassed by leukemias. Half of brain tumors in children are infratentorial with peak ages of 5 to 9 years. The annual incidence in children less than 15 years old is about 3 per 100,000. More than 1,200 new cases occur each year.

The cause of primary brain tumor is unknown. Some tumors (retinoblastoma, for example) tend to be hereditary. Others tumors (craniopharyngioma) are congenital.

Tumors may occur at any age, but many have a particular age group in which they are more common. The most common childhood brain tumors are astrocytoma, medulloblastoma, ependymoma, and brain stem glioma. Gliomas account for 75% of brain tumors in pediatrics, but only 45% in adults. Outside of retinoblastomas, most brain tumors are rare in the first year of life.

Specific symptoms, treatment, and prognosis (probable outcome) vary according to the site and type of the tumor and the age and general health of the person.

SPECIFIC TUMOR TYPE INFORMATION
Cerebellar astrocytoma:

• Accounts for 10 to 30% of pediatric brain tumors (peak age is 5 - 8 years old)
• Usually benign, cystic, and slow-growing
• Presenting signs usually include clumsiness of one hand, gait changes (stumbling to one side), headache, and vomiting
• There is a 38 to 94% cure rate based upon the tumor type
• The cornerstone of treatment is surgical resection
• If complete resection is not possible, radiation therapy may be beneficial
• Chemotherapy is usually reserved for the unresectable, progressive cases

• Most common pediatric brain tumor (20 to 25% of posterior fossa tumors)
• Occurs more frequently in boys than girls, and in infants more than older children and adults; peak age is 3 - 5 years old
• Presenting signs include headache, vomiting, ataxia, and lethargy
• Can spread (metastasize) along the spinal cord
• Surgical removal alone is not curative; radiation therapy or chemotherapy are often used
• About 30 to 50% of children are disease-free in 10 years
• If relapse occurs, it is usually within the first 5 years of therapy
• Children under 3 often have poorer outcomes because of the high incidence of metastatic disease at diagnosis in this age group; as well as lower doses of radiation used to reduce late effects of therapy

• Accounts for 8 to 10% of pediatric brain tumors (3rd most common)
• Tumor growth rates vary
• Tumors located in the ventricles of the brain and obstruct the flow of CSF
• Presenting signs include headache, vomiting, and ataxia
• Single or combination therapy includes surgery, radiation therapy, and chemotherapy
• Overall childhood survival is less than 30%; low-grade tumors have a 5-year survival rate of 80%; high-grade tumors may be fatal

• Tumors of the pons and medulla
• Occur almost exclusively in children
• Accounts for 10 to 15% of primary brain tumors in children; average age is 6 years old
• May grow to very large size before symptoms are present
• Presenting signs include: double vision, facial weakness, difficulty walking, vomiting
• Surgical removal is often difficult due to the location of the tumor
• Radiation therapy and chemotherapy are used to shrink the tumor size and prolong life
• Overall 5-year survival rate is 20-30%

• Tumor located near the pituitary stalk
• Often benign, but close to vital structure making surgical removal difficult
• Rare, less than 5% of childhood brain tumors; average age is 7 - 12 years old
• Presenting signs include vision changes, headache, weight gain, endocrine changes
• Treated with combination therapy, usually surgery and radiation therapy; there is some controversy over the optimal approach to therapy
• Survival and cure rates are favorable, though endocrine dysfunction may persist as well as the effects of radiation on cognition (thinking ability)

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