A metastatic brain tumor is brain cancer that has spread from another part of the body.
Brain tumor - metastatic (secondary); Cancer - brain tumor (metastatic)
Causes, incidence, and risk factors:
Many tumor or cancer types can spread to the brain, the most common being lung cancer , breast cancer , melanoma , kidney cancer , bladder cancer, certain sarcomas, testicular and germ cell tumors, and a number of others. Some types of cancers only spread to the brain infrequently, such as colon cancer, or very rarely, such as prostate cancer.
Brain tumors can directly destroy brain cells, or they may indirectly damage cells by producing inflammation, compressing other parts of the brain as the tumor grows, inducing brain swelling, and causing increased pressure within the skull .
Metastatic brain tumors are classified depending on the exact site of the tumor within the brain, type of tissue involved, original location of the tumor, and other factors. Infrequently, a tumor can spread to the brain, yet the original site or location of the tumor is unknown. This is called cancer of unknown primary (CUP) origin.
Metastatic brain tumors occur in about one-fourth of all cancers that metastasize (spread through the body). They are much more common than primary brain tumors . They occur in approximately 10 - 30% of adult cancers.
Note: Specific symptoms vary. The symptoms commonly seen with most types of metastatic brain tumor are those caused by increased pressure in the brain.
Signs and tests:
An examination reveals neurologic changes that are specific to the location of the tumor. Signs of increased pressure within the skull are also common. Some tumors may not show symptoms until they are very large. Then, they suddenly cause rapid decline in the person's neurologic functioning.
The original (primary) tumor may already be known, or it may be discovered after an examination of tumor tissues from the brain indicates that it is a metastatic type of tumor.
- A CT scan or MRI of the brain can confirm the diagnosis of brain tumor and identify the location of the tumor. MRI is usually better for finding tumors in the brain.
- Cerebral angiography is occasionally performed. It may show a space-occupying mass, which may or may not be highly vascular (filled with blood vessels).
- A chest x-ray , mammogram , CT scans of the chest, abdomen, and pelvis, and other tests are performed to look for the original site of the tumor.
- An EEG may reveal abnormalities.
- An examination of tissue removed from the tumor during surgery or CT scan-guided biopsy is used to confirm the exact type of tumor. If the primary tumor can be located outside of the brain, the primary tumor is usually biopsied rather than the brain tumor.
- A lumbar puncture (spinal tap) is sometimes also performed to test the cerebral spinal fluid.
Treatment depends on the size and type of the tumor, the initial site of the tumor, and the general health of the person. The goals of treatment may be relief of symptoms, improved functioning, or comfort.
Radiation to the whole brain is often used to treat tumors that have spread to the brain, especially if there is more than one tumor.
Surgery may be used for metastatic brain tumors when there is a single lesion and when there is no cancer elsewhere in the body. Some may be completely removed. Tumors that are deep or that infiltrate brain tissue may be debulked (removing much of the tumor's mass to reduce its size).
Surgery may reduce pressure and relieve symptoms in cases when the tumor cannot be removed.
Chemotherapy for brain metastases is not as helpful as surgery or radiation for many types of cancer.
Medications for some symptoms of a brain tumor may include the following:
- Corticosteroids such as dexamethasone to reduce brain swelling
- Osmotic diuretics such as urea or mannitol to reduce brain swelling
- Anticonvulsants such as phenytoin to reduce seizures
- Pain medication
- Antacids or antihistamines to control stress ulcers
When multiple metastases (widespread cancer) are discovered, treatment may focus primarily on relief of pain and other symptoms.
Comfort measures, safety measures, physical therapy, occupational therapy, and other interventions may improve the patient's quality of life. Legal advice may be helpful in forming advanced directives, such as power of attorney , in cases where continued physical or intellectual decline is likely.
In general, the probable outcome is fairly poor. For many people with metastatic brain tumors, the cancer spreads to other areas of the body. Death often occurs within 2 years.
- Brain herniation (fatal)
- Loss of ability to function or care for self
- Loss of ability to interact
- Permanent, progressive, profound neurologic losses
Calling your health care provider:
Call your health care provider if you develop a persistent headache that is new or different for you.
Call your provider or go to the emergency room if you or someone else suddenly develops stupor , vision changes, or speech impairment , or has seizures that are new or different.
Nguyen TD, Abrey LE. Brain metastases: old problem, new strategies. Hematol Oncol Clin North Am. 2007;21(2):369-388.
Nguyen TD, DeAngelis LM. Brain metastases. Neurol Clin. 2007;25(4):1173-1192.
Peak S, Abrey LE. Chemotherapy and the treatment of brain metastases. Hematol Oncol Clin North Am. 2006;20(6):1287-1295.
|Review Date: 6/10/2008|
Reviewed By: James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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