The goal of this phase II clinical trial is to evaluate the efficacy of the completely non-invasive treatment option of stereotactic radiation therapy for the treatment of biopsy proven and growing small renal tumors.

Current treatment options for primary renal cancer include surgery or ablative techniques-all are invasive or minimally invasive options. The completely noninvasive treatment option of stereotactic radiation therapy (SABR), which has become standard of care in many cancer sites, has not been explored for primary renal cancer. With multiple technological advances, it is now feasible to safely treat a moving intra-abdominal tumor such as that in a kidney. This proposed clinical trial evaluates the efficacy of SABR in treating patients with early renal cancers. Growing renal masses will first be biopsied to confirm the diagnosis of renal cancer. Patients will then undergo treatment with SABR of 3-5 fractions completing within three weeks. Treatment response will be evaluated using sequential MRI scans and a second tumor biopsy one year after treatment. Monitoring of treatment toxicity and kidney function will also be performed.

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.