• With interstitial brachytherapy , radioactive seeds are placed, with computer guidance, directly into a tumor
mass.
• Stereotactic radiosurgery ("gamma knife") directs many precisely focused external radiation beams at a tumor.
Using these techniques, a high dose of radiation may be given to a tumor while the surrounding brain is spared the adverse effects. These approaches require that the tumor be small to medium-sized and in an area of the brain that could tolerate a radiation injury without causing the loss of an important function. This approach has shown promise in the treatment of both primary and metastatic tumors and will likely play an increasing role in the future.
Chemotherapy Chemotherapy can be effective when used before or after surgery and
radiation. It can be used at the time of diagnosis and for a recurrence . Some tumors in the brain can be exquisitely sensitive to chemotherapy, including germinomas, lymphomas and oligodendrogliomas.
A roadblock to treating brain tumors with chemotherapy is that the drugs do not easily pass through the blood vessels in the brain into the brain substance where the tumor is located. Some experimental approaches have investigated ways to open this blood-brain barrier with drugs, while others have attempted to directly inject drugs into the major arteries feeding a tumor. Research is focused on developing drugs that have increased specificity for brain tumors and that can easily cross the blood brain-barrier.
