Radiation Therapy, Temozolomide, Tamoxifen, and Carboplatin in Treating Patients With Malignant Gliomas

RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Drugs used in chemotherapy, such as temozolomide and carboplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Tamoxifen may make tumor cells more sensitive to radiation therapy and chemotherapy. Giving radiation therapy together with temozolomide, tamoxifen, and carboplatin may kill more tumor cells. PURPOSE: This phase II trial is studying the side effects and how well giving radiation therapy together with temozolomide, tamoxifen, and carboplatin works in treating patients with malignant gliomas.