Diffuse Astrocytoma, IDH-Wildtype

This phase II trial studies how well temozolomide and radiation therapy work in treating patients with IDH wildtype historically lower grade gliomas or non-histological molecular glioblastomas. Radiation therapy uses high-energy x-rays to kill tumor cells and shrink tumors. Giving chemotherapy with radiation therapy may kill more tumor cells. Drugs used in chemotherapy, such as temozolomide, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. The goal of this clinical research study is to compare receiving new radiation therapy doses and volumes to the prior standard treatment for patients with historically grade II or grade III IDH wild-type gliomas, which may now be referred to as IDH wildtype molecular glioblastomas at some institutions. Receiving temozolomide in combination with radiation therapy may also help to control the disease.