Glioblastoma multiforme; Ependymoma; Glioma; Astrocytoma; Brain tumor - primary; Medulloblastoma; Neuroglioma; Oligodendroglioma; Meningioma; Cancer - brain tumor (primary)
A brain tumor is any growth of abnormal cells or uncontrolled proliferation of cells in the brain. Primary brain tumors involve any such growth that originates in the brain, rather than spreading to the brain from another part of the body.
Causes, incidence, and 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
- 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.
- Headache o Recent onset of new type o Persistent o Worse on awakening
- Vomiting o Possibly accompanied by nausea o More severe in the morning
- Personality changes and behavior changes
- Emotional instability, rapid emotional changes
- Intellectual decline o Loss of memory o Impaired calculating abilities o Impaired judgment
- Seizures, new onset
- Reduced level of consciousness (decreased alertness)
- Neurologic changes o Vision changes (double vision, decreased vision) o Hearing loss o Decreased sensation of a body area o Weakness of a body area o Speech difficulties o Decreased coordination, clumsiness, falls
- Fever (sometimes)
- Weakness, lethargy
- General ill feeling (malaise)
- Positive Babinski’s reflex
- Decerebrate posture
- Decorticate posture
- Bulging fontanelles
- Separated sutures
- Increased head circumference
- No red reflex in the eye
Note: Specific symptoms vary.
Additional symptoms that may be associated with primary brain tumors:
- Tongue problems
- Swallowing difficulty
- Impaired sense of smell
- Uncontrollable movement
- Dysfunctional movement
- Absent menstruation
- Hand tremor
- Facial paralysis
- Eye abnormalities o pupils different sizes o uncontrollable movements o eyelid drooping
- Breathing, absent temporarily
- Unusual or strange behavior
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
- Angiography of the head
- 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.
- Examination of the cerebral spinal fluid (CSF) may reveal cancerous cells.
This disease may also alter the results of a CPK isoenzymes test.
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) rather than removed.
Surgery may reduce intracranial pressure and relieve symptoms in cases when the tumor cannot be removed. Stereotactic (guided by CT) 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 the following:
- 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.
The stress of illness can often be helped by joining a support group where members share common experiences and problems. See cancer - support group.
Prognosis and outcome vary.
- Brain herniation (often fatal) o Uncal herniation o Foramen magnum herniation
- 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
Calling your health care provider
Call for an appointment with your health care provider if new, persistent headaches or other symptoms suggestive of a primary brain tumor occur.
Call your health care provider or go to the emergency room if seizures develop, or if there is the sudden development of stupor, vision changes, or speech changes.
by Gevorg A. Poghosian, Ph.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.