Radiation Therapy With or Without Temozolomide in Treating Patients With Low-Grade Glioma

RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. Drugs used in chemotherapy, such as temozolomide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. It is not yet known whether radiation therapy is more effective when given together with or without temozolomide in treating patients with low-grade glioma. PURPOSE: This randomized phase III trial is studying radiation therapy so see how well it works when given together with or without temozolomide in treating patients with low-grade glioma.