A brain tumor is a group of abnormal cells that grows in or around the brain. Tumors can directly destroy healthy brain cells. They can also indirectly damage healthy cells by crowding other parts of the brain and causing inflammation, brain swelling and pressure within the skull.
Brain tumors are either malignant or benign. A malignant tumor, also called brain cancer, grows rapidly and often invades or crowds healthy areas of the brain. Benign brain tumors do not contain cancer cells and are usually slow growing.
Brain tumors fall into two different categories: primary or metastatic. Primary brain tumors begin within the brain. A metastatic tumor is formed when cancer cells located elsewhere in the body break away and travel to the brain. For this reason, metastatic brain tumors are almost always malignant, while primary brain tumors may be benign or malignant.
Brain tumors are classified based on where the tumor is located, the type of tissue involved, whether the tumor is benign or malignant, and other factors. If a tumor is determined malignant, the tumor cells are examined under a microscope to determine how malignant they are. Based on this analysis, tumors are rated, or graded, by their level of malignancy from least to most malignant. Factors that determine the tumor grade include how fast the cells are growing, how much blood is supplying the cells, the presence of dead cells in the middle of the tumor (necrosis), if the cells are confined to a specific area, and how similar the cancerous cells are to normal cells.
The cause of primary brain tumors is unknown. Environmental and genetic factors may cause some brain tumors. Prior exposure to therapeutic irradiation as a child seems to be a contributing cause in very few patients. Symptoms of a brain tumor include headaches, nausea, vomiting, seizures, behavior changes, memory loss, and vision or hearing problems.
What are my treatment options?
A variety of therapies are used to treat brain tumors. The type of treatment recommended depends on the size and type of the tumor, its growth rate, brain location, and the general health of the patient. Treatment options include surgery, radiation therapy, chemotherapy, targeted biological agents, or a combination of these. Surgical resection (if safe) is generally the first treatment recommendation to reduce pressure in the brain rapidly. This website focuses on radiation therapy for brain tumors.
In the past two decades, researchers have developed new techniques of delivering radiation that target the brain tumor while protecting nearby healthy tissues. These treatments include brachytherapy, intensity-modulated radiation therapy (IMRT) and radiosurgery.
Radiation therapy may be advised for tumors that are sensitive to this treatment. Conventional radiation therapy uses external beams of x-rays, gamma rays or protons aimed at the tumor to kill cancer cells and shrink brain tumors. The therapy is usually given over a period of several weeks. Whole brain radiation therapy is an option in the case of multiple tumors or tumors that cannot be easily targeted with focal treatment.
Types of radiation therapy include:
- Intensity-modulated radiation therapy (IMRT): an advanced mode of high-precision radiotherapy that utilizes computer-controlled x-ray accelerators to deliver precise radiation doses to a malignant tumor or specific areas within the tumor. The radiation dose is designed to conform to the three-dimensional (3-D) shape of the tumor by modulating—or controlling—the intensity of the radiation beam to focus a higher radiation dose to the tumor while minimizing radiation exposure to healthy cells.
- Stereotactic radiosurgery (SRS): a highly precise form of radiation therapy that directs narrow beams of radiation to the tumor from different angles. For this procedure, the patient may wear a rigid head frame. Computed tomography (CT) or magnetic resonance imaging (MRI) help the doctor identify the tumor's exact location and a computer helps the doctor regulate the dose of radiation. Stereotactic radiotherapy is similar physically to radiosurgery but involves fractionation (multiple treatments). This modality would be recommended for tumors within or close to critical structures in the brain that cannot tolerate a large single dose of radiation or for larger tumors. .
- Three-dimensional conformal radiation therapy (3D-CRT): a conventional form of radiation treatment delivery that uses a specific arrangement of x-ray beams designed to conform to the shape of the tumor to maximize tumor dose and minimize normal surrounding tissue dose. This form of treatment is tailored to the patient's specific anatomy and tumor location. CT and/or MRI scan is often required for treatment planning.
- Brachytherapy: the temporary placement of radioactive source(s) within the body, usually employed to give an extra dose—or boost—of radiation to the area of the excision site or to any residual tumor.
Surgery, also called surgical resection, is often indicated for primary brain tumors. A surgeon removes some or the entire tumor without causing severe damage to surrounding tissues. Surgery may also be used to reduce pressure within the skull (called intracranial pressure) and to relieve symptoms (called palliative treatment) in cases when the tumor cannot be removed.
Chemotherapy, or anticancer medications, may be recommended. Chemotherapy, along with radiation (concurrent therapy), has become the standard of care for primary malignant brain tumors. The use of these drugs or chemicals to slow down or kill rapidly dividing cells can be used before, during, or after surgery and/or radiotherapy to help destroy tumor cells and to prevent them from returning. Chemotherapy drugs may be taken by pill or by injection and are often used in combination with radiation therapy. Drugs called radiosensitizers, which are believed to make radiation therapy more effective, may also be prescribed.
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