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Primary brain tumor, or glioma, originates in the brain. Gliomas include astrocytomas, glioblastomas, ependymomas, oligodendrogliomas and mixed gliomas.
Secondary brain tumors are considered metastatic because they originate in another part of the body and spread to the brain. A neuropathologist examines tumor tissue in order to determine tumor grade.
Brain tumor diagnosis is confirmed after a patient experiences symptoms such as headaches, nausea or vomiting, changes in speech or behavior patterns, problems with balance or coordination, memory deficit, numbness or tingling in extremities and seizures or convulsions. If a patient has symptoms suggestive of a brain tumor, a physician may perform a physical exam, where the patient's general health is assessed, and a neurological exam, where the physician examines alertness, muscle strength, pain response, coordination and reflexes.
If findings are significant, the physician may order a CT scan, where an x-ray machine takes detailed images of the head, or an MRI, where magnetic resonance imaging is reviewed on a computer screen to assist in diagnosis. Other tests that may be ordered are: an angiogram, myelogram, spinal tap or skull x-ray.
If a tumor is identified through any of these mechanisms, the physician may order a biopsy of the tumor tissue. A biopsy is the only definite method in diagnosing a brain tumor. Types of biopsies include: a needle biopsy, where a needle is inserted, and a small hole in the skull, known as a burr hole is created. The physician uses a needle to extract sample tissue through the burr hole, where it is then examined under a microscope by the pathologist. Another type of biopsy, called stereotactic biopsy may be employed. During this process, a physician utilizes images from either CT or MRI to guide a needle through the burr hole, where a tumor tissue sample is then obtained. A third type of biopsy is taken when the tumor is removed from the brain. In this instance, a surgeon removes a portion of the tissue from the extracted brain tumor, and sends it to a pathologist for review.
Following biopsy, the pathologist will determine tumor type and grade. A Grade I tumor is considered low-grade because it grows slowly and rarely spreads to normal tissue. A Grade II tumor grows slowly, but is different from a Grade I tumor because it spreads to nearby tissue, and has a possibility for recurrence. A Grade III tumor grows quickly, is likely to spread to nearby tissue, and the tumor cells are easy to differentiate from normal cells. A Grade IV tumor is considered high-grade. It grows and spreads rapidly, and may contain areas of dead cells.
The physician makes a treatment recommendation, depending on tumor grade. A patient may either choose to undergo standard or experimental treatment. Standard treatment is a currently used treatment, while experimental treatment includes use of clinical trials. If a clinical trial proves to be better than standard treatment, it may become the new standard treatment. Some clinical trials are only open to patients who have not already undergone treatment, so it is important for patients to consider all options when making an initial treatment decision. Please visit the Clinical Trials page for more information on trials offered at the Arizona Cancer Center.
The three types of standard treatment include: surgery, chemotherapy and radiation therapy. During surgery, even if the neurosurgeon is able to remove the entire tumor, a patient may undergo chemotherapy and radiation to ensure that any possible tumor cells will be killed. Chemotherapy is medication used to prevent the growth of cancer cells, and can be administered either systemically, or locally, depending on tumor grade, and where it is located in the brain. Radiation therapy uses high-energy x-rays to destroy cancer cells and prevent further growth. External beam radiation uses an external machine to navigate radiation toward the cancer site. Hyperfractionated radiotherapy is one type of external beam radiotherapy in which daily doses of radiation may be given a few hours apart. Internal radiation, or brachytherapy, is administered internally to the site by use of a sealed instrument, such as a needle, seed, wire or catheter.