Stereotactic radiosurgery, or SRS, is a special form of radiation therapy. It is not surgery.
Radiation either kills tumor cells directly or interferes with their ability to grow. However, radiation cannot tell the difference between tumor cells and healthy cells—it affects both. That’s why scientists developed SRS, a special type of radiation that allows precisely focused, high-dose x-ray beams to be delivered to a small, localized area of the brain. Because SRS focuses the beams more closely to the tumor than conventional radiation, it can deliver a higher, more effective dose of treatment to the tumor site. This highly focused form of radiation is called radiosurgery.
SRS is used to treat small brain and spinal cord tumors (benign and malignant), blood vessel abnormalities in the brain, defined areas of cancer, certain small tumors in the lungs and liver, and neurologic issues such as movement disorders. It can also be used as a tumor-targeted “boost” at the end of conventional radiation therapy.
How Stereotactic Radiosurgery is Delivered
Focusing the radiation tightly on the tumor is possible through the use of highly specialized computer-assisted equipment. A head frame or face mask used for this treatment allows very precise setup, localization, and treatment of the tumor. Using advanced computer planning, radiosurgery minimizes the amount of radiation received by normal brain tissue and focuses radiation in the area to be treated.
At the time of treatment, an intravenous (IV) line is started to provide easy access for delivery of steroids or relaxing medications, if needed. Some forms of radiosurgery require the patient to wear a lightweight head frame (“halo”) or a face mask. This equipment is designed to help the doctor define the exact location of the tumor and keep the head from moving during treatment. Once the head frame or face mask is in place, scans are taken and the treatment plan is calculated. The actual treatment can range from 15 minutes to about two hours. Once treatment is complete, the head frame or face mask is removed and the patient returns home. Occasionally, a patient might be kept overnight for observation. Most patients feel able to resume their usual activities within a day or two.
Potiential Side Effects
Some people have few or no side effects from SRS. Side effects experienced are usually due to brain edema (swelling) caused by the radiation. These symptoms can include:
Hair loss in the area treated may be seen two or three weeks following the procedure. It depends on the dose of radiation received and the ability of the radiated hair follicles to heal. Regrowth usually begins in three to four months, and may be a slightly different color and/or texture than before. The scalp may also become temporarily irritated.
Some patients may experience delayed reactions weeks or months after treatment. These reactions can include cell death in the high radiation dose region due to the radiation effect, or radionecrosis. Symptoms may be similar to the symptoms of tumor regrowth or stroke. Your treatment team can provide more specific information about side effects and how to manage them.
It is important to note that the information provided here is basic and does not take the place of professional advice. If you have any questions about how brain tumors are treated, please contact your doctor.