Primary Brain Tumor

Pictures & Images

See all Pictures & Images

Overview, Causes, & Risk Factors

Primary brain tumors include any tumor that originates in the brain. Tumors may be localized to a small area, invasive (spread to nearby areas), benign (noncancerous) or malignant (cancerous).

Tumors can directly destroy brain cells. They can also indirectly damage cells by producing inflammation, compressing other parts of the brain as the tumor grows, inducing cerebral edema (brain swelling), and causing increased intracranial pressure (the pressure within the skull).

Classification of brain tumors depends on the exact site of the tumor, the type of tissue involved, benign or malignant tendencies of the tumor, and other factors. The cause of primary brain tumors is unknown. Some tumors (retinoblastoma, for example) tend to be hereditary. Others tumors (craniopharyngioma) are congenital (present from before birth).

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

Childhood nervous system tumors may be classified as either infratentorial (located below the tentorium cerebelli), meaning they are in the posterior third of the brain, or as supratentorial meaning they are within the anterior two-thirds of the brain.

Central nervous system tumors account for about 20% of all childhood cancers. They are second in incidence only to leukemias. Half of brain tumors in children are infratentorial. 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.

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 to 8 years old)
• Usually benign, cystic and slow-growing
• Signs usually include clumsiness of one hand, gait changes (stumbling to one side), headache, and vomiting.

The cornerstone of treatment is surgical removal of the tumor. If complete removal is not possible, radiation therapy may be beneficial. Chemotherapy is usually reserved for unremovable, progressive cases. There is a 38% to 94% cure rate based upon the tumor type

• Most common pediatric brain tumor (20% to 25% of posterior fossa tumors)
• Occurs more frequently in boys than in girls; peak age is 3 to 5 years old
• Signs include headache, vomiting, ataxia, and lethargy.
• Can spread (metastasize) along the spinal cord

Surgical removal alone does not cure medullablastoma; radiation therapy or chemotherapy are often used with surgery.

Children younger than 3 often have poorer outcomes. There is a high incidence of metastatic disease at diagnosis in this age group, and low doses of radiation are used in these patients.

• 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.

• Accounts for 8% to 10% of pediatric brain tumors (third most common)
• Tumor growth rates vary.
• Tumors are located in the ventricles of the brain and obstruct the flow of cerebrospinal fluid (CSF).
• 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
• 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% to 30%.

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

There is some controversy over the optimal approach to therapy for craniopharyngioma.