Metastatic Tumor

Cells from a cancer can break off and travel through the blood or lymphatic system until they reach a location in the body distant from their tumor of origin where they then grow and multiply forming a new and separate tumor called a "metastasis". The most common brain tumor in adults is actually metastatic brain tumor. It is approximately 50% of brain tumors in adults. Brain metastastes are very common with cancer. The number of cancer patients with brain metastasis at autopsy is 15% to 20%. Brain metastasis may cause the first symptoms that the patient has of cancer. This occurs in up to 15% of cancer patients. The cancers which are most likely to form metastasis in the brain are cancers of the lung and breast (more than 50% of brain metastasis are from lung and breast). Kidney, gastrointestinal and melanoma cancers also form brain metastasis. The location of most brain metastasis is in the hemispheres of the brain where the temporal, parietal and occipital lobes are located. Brain metastasis can also spread to the cerebellum. Tumors in other parts of the body can also spread to the meninges around the brain (see discussion of carcinomatous meningitis).

The symptoms of brain metastasis include those of brain tumors in general such as increased intracranial pressure with headache, nausea and vomiting. There can also be local problems of brain function such as weakness, numbness or problems with cranial nerve function. Seizures occur in 15% of patients with brain metastasis. Depression, apathy, confusion and other changes in behavior are also symptoms of brain metastasis. Finally, brain metastasis can present like a stroke with a sudden onset of a neurologic problem.

The diagnosis of cerebral metastasis includes imaging by CT or MR scan. In addition the patient who has a suspected cerebral metastasis should have chest x-ray and other studies done to try to find the origin tumor.

The treatment of cerebral metastasis includes medical treatment with anti-seizure medications and steroids. Radiation is another treatment approach with either whole brain radiation or more recently with radiosurgery (or the variation Gamma Knife). Lung metastasis to the brain are somewhat responsive to radiation therapy, however melanoma has almost no response to either chemotherapy or radiation therapy. Surgery is indicated for cerebral metastasis when the primary tumor is not active. The metastatic lesion should also be very accessible. In addition, a patient with cerebral metastasis should be symptomatic and surgery should be life saving. Whatever treatment approach is taken is generally for palliation (relief of symptoms), but not to cure.