Within 2 weeks of planned SAbR, patients will have a core biopsy of the lesion to receive SAbR. Laboratory values will be obtained prior to biopsy. Once the laboratory values are found to be within the safe margin for biopsy, multiple (approximately 5) core biopsies will be obtained with an 18-guage or 19-gauge needle under CT or US guidance. Tissue will be snap frozen with liquid nitrogen and immediately transferred to the laboratory of Dr. Zhijian "James" Chen, PhD, Professor, Department of Molecular Biology.

SAbR will be administered as per the guidelines of UTSW with a single 24-27Gy or three 10-14 Gy/fraction fractions totaling 33-48Gy. Lesions receiving SAbR will be called "radiated" lesions. Prior irradiated lesions will be excluded. SABR will be administered within 2 weeks of the study initial core biopsy. The SAbR dose and fractionation scheme is generated to deliver a potent dose to ablate the targeted lesions and at the same time maximize an immune response. Since multiple studies have shown an influx of lymphocytes and monocytes after tumor irradiation and since these cells play a critical role in antigen presentation and initiation of an adaptive immune response, multiple fraction irradiation which would kill these infiltrating immunocytes, is discouraged. Therefore a single fraction or a three fraction treatment regimen is recommended, and a single fraction treatment is preferred over three fractions. Due to normal organ toxicity and limits of dose constraints, sometimes a three fraction treatment must be undertaken and in those cases it is recommended that the treatment course is completed within 7-10 days-preferably 5 business days. Radiation dose-immune response studies have shown a linear increase in immune response with increased dose per fraction of radiation without demonstration of a plateau. Two studies comparing 15Gy x 1 vs 5Gy x3, and 20Gy x1 vs 5Gy x4 have shown a superior immune response generated by the single fraction radiation. Clinical experience with oligometastatic patients treated at 1-5 sites of disease has also showed an increase in progression-free survival with the increasing radiation dose per fraction. A dose of less than 7.5 Gy per fraction has demonstrated lower induction of systemic IFN-γ producing cells, and a previous phase II study of mRCC patients treated with HD IL-2 and singe fraction of 8Gy irradiation to a single lesion did not show an overall improvement in response rate. Therefore 8Gy per fraction is the lowest permitted dose for this study and can be used only when administering the three fraction regimen as described in the prescription dose table below. Investigators will have discretion in choosing from either of the biologically equivalent dose levels using one or three fractions, although a single fraction is preferred over three fraction treatments. Treating physician will have further discretion in selecting the number and location of sites to treat if multiple sites of disease are present. Maximum number of lesions treated is deemed as feasible per the treating radiation oncologist. However, for the purposes of this protocol, only a single site will be studied and must be safely amenable to repeat core biopsy. Thus, the single site for the study will be either in subcutaneous tissues, nodes, isolated masses or liver. The gross target/tumor volume--GTV should be at least 2 cm3 in size, corresponding to roughly a 1.5 cm diameter tumor. This is to ensure that adequate tumor volume for therapy and for biopsy and therefore adequate tumor cells roughly 108 -109 cells/cm3 are killed for antigen presentation. Treating physicians should choose their dose based on established planning guidelines at their center including their ability to respect normal tissue tolerance.

Within 24 + 6 hours of the first SAbR, a second core biopsy of the "target" irradiated lesion will be performed identically to the first biopsy.