What to Know About Radiation Therapy for Brain Tumors

Radiation therapy uses high-energy radiation to kill cancer cells. Radiation therapy controls about one-half of all medulloblastomas, which grow in the lower part of the brain. It controls almost all germinomas, which grow in the sex cells. Radiation does not cure most brain tumors. Most brain tumors eventually come back.

Doctors give this treatment in one of these two ways.

• From a machine outside the body, called external beam radiation

• From small radioactive pellets placed inside the area with cancer, called interstitial therapy

Your doctor may give you both types of treatment.

Radiation can harm normal brain cells. To limit the damage, your doctor will focus high doses directly on the tumor. One way to do this is with 3-D conformal therapy. In this treatment, doctors use computers and CT scans to match the radiation beam to the shape of the tumor.

Another way to minimize damage is stereotactic radiosurgery (SRS). It can be used on small tumors. Once doctors know the size and location of the tumor, they give a high-energy dose of radiation to the tumor from many different angles. These are the 3 types of SRS.

• Gamma knife radiation

• Proton beam

• Linear accelerator (LINAC)

Your doctor may use SRS as an additional treatment if you’ve had the maximum dose of radiation but your cancer has returned.

You’ll have imaging tests to see if the cancer has spread to other parts of your brain and your spinal cord. If the cancer has spread, you may have radiation to your whole brain and spinal cord.