For malignant lesions, even when it appears that all tumor has been removed, microscopic cells remain in the surrounding brain tissue. To prevent or delay recurrence, radiation therapy to treat these areas is recommended. Other benign brain tumors are treated with radiation at time of recurrence. Traditional radiation therapy uses external beams of either x or gamma rays to destroy brain tumor cells. This therapy delivers radiation from outside the patient's body and usually begins a week or two after surgery, after the surgical incision heals, continuing with fairly uniformed dosages throughout the treated areas for approximately six weeks.
Radiation is considered a local treatment because only cells in the area being treated are affected.
It can be used at various phases of cancer treatment. Radiation may be used in early stage cancers in an attempt to cure or control the disease. It can be used before surgery to shrink the tumor or following surgery to prevent the cancer from coming back. In advanced cancer, radiation may be used to treat symptoms such as pain caused by the cancer. In these cases, the treatment plan will be coordinated with the patient between the surgeon, medical oncologist and radiation oncologist.