The symptoms of a metastatic brain tumor depend on its location and size. As a brain tumor grows, it may interfere with the normal functions of the brain and depending on the location may cause headaches, nausea, seizures, weakness or numbness in the limbs or face, visual problems, and gradual changes in mood or personality. The symptoms tend to increase in severity as the tumor grows in size. Headache and nausea, usually are the result of increased intracranial pressure caused by the mass of the tumor in the brain or from a backup of the cerebrospinal fluid that surrounds the brain and spinal cord.
These tumors are diagnosed with a neurological examination followed by imaging studies of the brain, usually a computed tomography (CT) or magnetic resonance imaging (MRI) scan. Sometimes a brain scan is part of the initial screening process when the primary cancer is diagnosed or is obtained if a patient begins to have symptoms of a brain or spinal tumor. The scan is usually performed with a contrast dye that makes the border and details of the tumor more visible in relation to the surrounding normal brain. The scan provides detail information regarding the exact number, size and location of the tumor. Neurosurgeons will often employ a stereotactic MRI scan. In this study, a high-resolution contrast MRI is performed and a three-dimensional brain model is constructed using a computer system that is used to perform minimally invasive surgery or Stereotactic Radiosurgery (CyberKnife and Gamma Knife).
Although the MRI scans provide a probable diagnosis, only examination of a patient’s tumor tissue under a microscope can confirm an exact diagnosis. This tissue is usually obtained with a biopsy or tumor resection if indicated. If a metastatic tumor is diagnosed before the primary cancer site is found, tests to locate the primary site will follow. These tests may include blood tests, a chest, abdominal and pelvic CT, a body PET scan, or other tests as needed. The pathology report of tissue collected during surgery can also help the doctor determine possible sites of the primary cancer if testing fails to do so.
Treatment for a metatstaic brain tumor involves the close cooperation of an oncologist, radiation oncologist and neurosurgeon. The neurosurgeon will look at the scans to determine if the tumor(s) can be surgically removed, or if other treatment options are more reasonable. Depending on the patient’s overall health, the number of metastatic tumors, and their location and size, metastatic brain tumors may be treated with one or a combination of techniques. Treatment decisions will take into account not only long-term survival possibilities, but quality of life during and after treatment, as well as cognition concerns.
Minimally invasive stereotactic surgery is preferred when a symptomatic or large solitary tumor can be completely removed without causing any neurological damage. Usually surgery is performed with a frameless stereotactic navigation system in which a high-resolution MRI is used to construct a 3-dimensional brain model – much like a GPS system - that allows for minimally invasive volumetric brain surgery. In some cases, depending on the location of the tumor, the neurosurgeon may employ advanced techniques that enable safe removal of a tumor even in eloquent parts of the brain. Some of these techniques include functional brain mapping to identify the location of movement, sensation and language centers in the brain. This is performed with intraoperative electrical stimulation of the brain, functional MRI scans and occasionally by performing the surgery awake in order to monitor and evaluate these functions during the operation.
Stereotactic Radiosurgery (CyberKife and Gamma knife) radiosurgery uses a single, high dose of radiation to stop a metastatic tumor from growing, and is, alone, very effective in controlling individual small metastatic tumors. Stereotactic Radiosurgery uses numerous finely focused beams of radiation to accurately target the tumor and while minimizing the effects to any surrounding tissue. The target tumor is usually outlined on a 3-Dimensional model of the brain by the neurosurgeon and the radiation oncologist prior to the procedure.
Whole brain radiation is used if multiple metastatic brain tumors are present and the patient is not a candidate for stereotacic radiosurgery or open surgery. In general, surgical resection of a metastatic tumor is followed with either Stereotactic Radiosurgery or whole brain radiation to prevent tumor recurrence following surgical resection. Systemic chemotherapy and immunotherapy use medications to kill cancer cells and enlist the body’s immune system in fighting the disease.
After surgery, each patient is reviewed at our Multi-Disciplinary Tumor Board with an expert team of neuro-oncologists, medical oncologists, neuro-pathologists, neuro-radiologists and neurosurgeons. Together the tumor board recommends the best treatment options for each patient, incorporating ongoing national clinical trials and the latest treatment protocols.