Tumor Resection and Gliadel® Wafers, Followed by Temodar® With Standard Radiation or GammaKnife® for New GBM

A glioblastoma (GBM) is the most common malignant primary brain tumor, yet it is not easy to control. Recent studies show that survival improves for patients who get aggressive surgery to remove a tumor before starting radiation (RT) and chemotherapy (chemo) treatment. Surgery, RT and chemo are part of regular cancer care for GBM. RT is usually done in daily doses 5 days a week over about 6 weeks. Beams of radiation are aimed at the tumor site plus some of the normal brain tissue around the tumor area. GammaKnife® (GK) radiosurgery also delivers radiation but in a larger dose over one day. GK sends beams to a precise target (tumor location) and very little normal brain tissue that is nearby. This study will compare GK treatment to the usual RT treatment after surgery, and with chemo. We want to know: * How well each treatment keeps the tumor from growing back. * What the effects (good and bad) of the treatments are. * How you rate your quality of life. * How the treatment affects your ability to think, understand, reason, and remember. * How you rate your ability to think, understand, reason, and remember. * If using a certain type of MRI scan can show the difference between new tumor growth and changes caused by treatment. * If certain features found in tumor cells can help doctors predict how tumors will respond to treatment.