Stereotactic Ablative Body Radiation Therapy for Patients With Primary Renal Cancer

Inclusion Criteria * Age ≥ 18 years. * Renal mass ≤ 5cm * The treating renal mass must be ≤ 5cm. Other renal masses (cysts etc.) of any size will not make the subject ineligible * Biopsy proven Renal neoplasm * All histology of renal cancers are included including oncocytoma * Growth of renal mass \>2mm in radiographic scans must be demonstrated within a one year period. * Ability to understand and the willingness to sign a written informed consent. * Subject is able to undergo either an MRI or administration of contrast agent for CT * Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) for the duration of the study. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. * A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: * Has not undergone a hysterectomy or bilateral oophorectomy; or * Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months). Exclusion Criteria: * Subject has received any treatment for the treating renal mass; such as RFA or cyroablation. * If other renal masses received RFA or cryoablation or surgery, then these patients are eligible. * Subjects received previous abdominal radiation * Evidence of Metastatic Disease, unless disease-free for ≥ 3 years prior to registration, (non-melanomatous skin cancer and in-situ cancers are okay). * Female subjects who are pregnant or planning to become pregnant during the course of SABR.