Radiation Therapy With or Without Temozolomide in Treating Women With Brain Metastases and Breast Cancer

RATIONALE: Radiation therapy uses high-energy x-rays to kill 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 or by stopping them from dividing. It is not yet known whether radiation therapy is more effective when given alone or together with temozolomide in treating brain metastases secondary to breast cancer. PURPOSE: This randomized phase II trial is studying how well radiation therapy given together with temozolomide works compared with radiation therapy given alone in treating women with brain metastases and breast cancer.