The purpose of this study is to determine the safety and efficacy of combined stereotactic body radiotherapy (SBRT) + sorafenib in the treatment of patients with Stage IV renal cell carcinoma (RCC) who have recurred locally, developed progression of an unresectable primary or progression of extra-cranial and/or extra-pulmonary metastases while on sorafenib. All subjects will remain on sorafenib during SBRT.