A mass created by growth of abnormal cells or uncontrolled proliferation of cells in the brain. Primary brain cancer originates in the brain. Other names for this type of cancer include – Glioblastoma multiforme, Ependymoma, Glioma, Astrocytoma, Medulloblastoma, Neuroglioma, Oligodendroglioma, and Meningioma.

Secondary brain cancer originates as a primary cancer in a different part in the body which moves (metastases) into the brain.

Causes and Risks

Primary brain tumor includes 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 also can cause indirect damage to cells from inflammation, compression from growth of the tumor, cerebral edema (brain swelling), and increased intracranial pressure (the pressure within the skull).

Classification of brain tumors depends on the exact site of the tumor, type of tissue involved, benign or malignant tendencies of the tumor, and other factors. Childhood nervous system tumors are classified as 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 2nd in incidence, only surpassed by leukemias. Two-thirds 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 2.4 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.

Prevention is unknown.

Specific Tumor Types

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
• Single or combination therapy includes surgery, radiation therapy, and chemotherapy

Medulloblastoma

• 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; peakage 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 and/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 4 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

Ependymoma

• 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

Brainstem Glioma

• 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 to 30%

Craniopharyngioma

• 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)

Symptoms

• Headache (recent onset of new type, persistent, worse on awakening)
• Vomiting (possibly accompanied by nausea, more severe in the morning)
• Personality changes and behavior changes
• Emotional instability, rapid emotional changes
• Intellectual decline (loss of memory, impaired calculating abilities, impaired judgment)
• Seizures, new onset
• Reduced level of consciousness (decreased alertness, stupor)
• Vision changes (double vision, decreased vision)
• Hearing loss
• Decreased sensation of a body area
• Weakness of a body area
• Speech difficulties
• Decreased coordination, clumsiness, falls
• Fever (sometimes)
• Weakness, lethargy
• General ill feeling (malaise)
• Positive Babinski?s reflex
• Decerebrate posture
• Decorticate posture

Symptoms in Infants

• Bulging fontanelles
• Sutures – separated
• Opisthotonos
• Increased head circumference
• No red reflex in the eye

Note: Specific symptoms vary.

Additional Symptoms That May Be Associated With This Disease

• Tongue problems
• Swallowing difficulty
• Smell, impaired
• Obesity, onset
• Movement, uncontrollable
• Movement, dysfunctional
• Menstruation, absent
• Hiccups
• Hand tremor
• Facial paralysis
• Eyes, pupils different size
• Eye movements, uncontrollable
• Eyelid drooping
• Confusion
• Breathing, absent temporarily
• Behavior, unusual or strange

Signs and Tests

Examination often shows focal (isolated location) or general neurologic changes that are specific to the location of the tumor. Some tumors may not show symptoms until they are very large and cause rapid neurologic decline, others are characterized by slowly progressive symptoms. Most brain tumors will include signs typical of space-occupying masses (aggregations of cells) which cause increased intracranial pressure and compression of brain tissue.

The diagnosis may be confirmed, and the tumor localized, by:

• CT scan of the head
• MRI of the head
• Angiogram of the head shows a space-occupying mass, which may or may not be highly vascular.
• EEG may reveal focal (localized) abnormalities.
• Examination of tissue removed from the tumor during surgery or CT scan-guided biopsy is used to confirm the exact type of tumor.

This disease may also alter the results of a CPK isoenzymes test.

Treatment

A primary brain tumor should have prompt treatment. Early treatment improves the chance of a good outcome for many tumors.

Treatment varies with the size and type of the tumor and the general health of the person. The goals of treatment may be cure of the disorder, relief of symptoms and improvement of function, or comfort.

Surgery is indicated for most primary brain tumors. Some may be completely excised (removed). Tumors that are deep, or that infiltrate brain tissue, may be debulked (removal of much of the mass of the tumor to reduce its size). Surgery may reduce intracranial pressure and relieve symptoms in cases when the tumor cannot be removed. Stereotactic (CT scan-guided) surgery may be helpful in removing deep tumors.

Radiation therapy may be advised for tumors that are sensitive to this treatment. Anticancer medications (chemotherapy) may be recommended.

Other medications may include:

• Corticosteroids such as dexamethasone to reduce brain swelling
• Osmotic diuretics such as urea or mannitol to reduce brain swelling (and associated increased intracranial pressure)
• Anticonvulsants such as phenytoin to reduce seizures
• Analgesics to control pain
• Antacids or histamine blockers to control stress ulcers

Comfort measures, safety measures, physical therapy, occupational therapy, and other such steps may be required to improve quality of life. Counseling, support groups, and similar measures may be needed to help in coping with the disorder.

Legal advice may be helpful in formulating advanced directives, such as power of attorney, in cases where continued physical or intellectual decline is likely.

Prognosis and outcome vary.

Complications

• Brain herniation (often fatal)
• Permanent, progressive, profound neurologic losses
• Loss of ability to interact
• Loss of ability to function or care for self
• Side effects of medications, including chemotherapy
• Side effects of radiation treatments
• Recurrence of tumor growth
• death

Dr. Charles L. Schulman, M.D.
Dr. Schulman practices medicine at Cardiology Asosciates of Boston, and is an Assistant Clinical Professor at Harvard Medical School.