SAbR For Oligometastatic Renal Cell Carcinoma

Hypothesis: Stereotactic ablative body radiation (SAbR) prolongs progression-free survival for patients with oligometastatic kidney cancer (RCC) and delays the initiation of systemic therapy. Primary Objectives: • To evaluate the delay in time to start of systemic therapy (TTST) as a surrogate of progression free survival (PFS), defined as the time from the first day of SAbR to start of systemic therapy. Secondary Objective: * To evaluate the modified progression-free survival (mPFS) for patients with oligometastatic renal cell carcinoma who are treated with SAbR. * To evaluate the overall survival (OS) * To evaluate the cancer specific survival (CSS) * To evaluate the local control rate of irradiated lesions. * To measure the health-related quality of life (HRQOL).

Inclusion Criteria: * Metastatic renal cell carcinoma with limited measurable extracranial metastases (Limited metastases, or oligometastases, defined as ≤3 sites of metastasis). * Radiographic evidence of metastatic disease. CT should be performed within 30 days of registration. * Pathology confirmation of Renal cell carcinoma. * Prior surgery, or radiation is permitted. * Age ≥ 18 years. * Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, and for 90 days after Radiation treatment has been completed . 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). * Ability to understand and the willingness to sign a written informed consent and agrees to undergo image studies and follow up Exclusion Criteria: * Subjects with brain metastasis as assessed by contrast MRI or contrast CT scans(contrast recommended). * Subjects with previous history of brain metastasis. * Subjects that received prior systemic therapy for kidney cancer in the past 1 year, except one line of immuno- or cytokine therapy (e.g. prior IL-2); systemic therapy for other cancers does not apply to this exclusion criteria * Subjects with ≥3 unfavorable prognostic factors defined by Motzer et al. (1999), (KPS \1, Hgb \< LLN, LDH \>1.5x normal, corrected serum calcium \>10mg/dl and absence of prior nephrectomy), Patients with 0, 1-2, and ≥3 factors had time to death of 20 months, 10 months and 4 months. * Subjects with life expectancy \< 6 months. * Subjects receiving any other investigational agents * Subjects must not be pregnant due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants.