Lapatinib and Radiation Therapy in Treating Patients With Locally Recurrent or Chemotherapy-Refractory Locally Advanced or Metastatic Breast Cancer

RATIONALE: Lapatinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving lapatinib together with radiation therapy may kill more tumor cells. PURPOSE: This phase I trial is studying the side effects and best dose of lapatinib when given together with radiation therapy in treating patients with locally recurrent or chemotherapy-refractory locally advanced or metastatic breast cancer.