SAbR For Oligometastatic Renal Cell Carcinoma

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.

Modified progression-free survival (mPFS) for patients with oligometastatic renal cell carcinoma who are treated with SAbR. Modified progression-free survival (mPFS) is defined as the survival interval without development of >3 sites of new metastasis, new sites of metastases that are not amenable to SAbR treatment, a total of >6 sites of metastasis that required SAbR, local failure at SAbR-treated site, or development of brain metastasis, with the definition of new metastasis and local failure (progression) as defined by RECIST. "Metastasis" in this entire protocol refers to extra-cranial metastasis unless otherwise specified.

To evaluate progression on next line of systemic therapy as defined by RECIST 1.1 starting from mPFS (modified progression free survival). Response and progression will be evaluated in this study using the new international criteria proposed by the Response Evaluation Criteria in Solid Tumors (RECIST v 1.1) Committee [Eur J Cancer. 2009;45(2):228-247]. Changes in only the largest diameter (unidimensional measurement) of the tumor lesions are used in the RECIST v1.1 criteria.

Overall survival (OS), which is defined as the time between date of registration and the date of death due to any cause.

Cancer specific survival is defined as the time between date of registration and the date of death due to renal cell carcinoma.

Radiographic progression with >30% increase in the longest diameter of the treated lesions.

Median response duration is defined as the time between the date a response (CR or PR) was first seen until date of progression. Response and progression will be evaluated in this study using the new international criteria proposed by the Response Evaluation Criteria in Solid Tumors (RECIST v 1.1) Committee [Eur J Cancer. 2009;45(2):228-247]. Changes in only the largest diameter (unidimensional measurement) of the tumor lesions are used in the RECIST v1.1 criteria.

Interval time to development of new lesions that can be treated with additional local therapy- title would be this or a shortened version of it. Time to event will be estimated using the Kaplan-Meier approach along with the 95% confidence interval.

To measure the time interval from registration to time to disease progression that cannot be treated with further local therapy and need to initiate or switch systemic therapy. Time to event will be estimated using the Kaplan-Meier approach along with the 95% confidence interval.

Severity or Toxicity will be assessed according to the National Cancer Institute (NCI) Common Toxicity Criteria for Adverse Events (CTCAE), version 5.0. Dose adjustments should be made according to the system showing the greatest degree of toxicity. The consequences of toxicity should all be graded 1-5 according to the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0 occurring prior to 270 days from the start of protocol treatment. Other treatment related toxicity attributed to the therapy will be captured, recorded and the consequences of should all be graded 1-5 according to the Common Terminology Criteria for Adverse Events (CTCAE). CTCAE V5.0 along with grades 1-5.

HRQOL will be measured using FACT-G questionnaire at baseline and at first follow up 8-12 weeks (+/- 4 weeks) then 12 week (±4 week) intervals for 1 year, and every 26 weeks (±4 weeks) until the completion of follow ups. FACT-G is a measure that sums the functional well being (FWB), physical well being (PWB), the social/family well-being (S/FWB), and emotional well being (EMB).

HRQOL will be measured using EQ-5D (EuroQol- 5 Dimension) questionnaire at baseline and at first follow up 8-12 weeks (+/- 4 weeks) then 12 week (±4 week) intervals for 1 year, and every 26 weeks (±4 weeks) until the completion of follow ups. EQ-5D-5L is a self-assessed, health related, quality of life questionnaire. The scale measures quality of life on a 5-component scale including mobility, self-care, usual activities, pain/discomfort, and anxiety/depression.

HRQOL will be measured using FKSI questionnaire at baseline and at first follow up 8-12 weeks (+/- 4 weeks) then 12 week (±4 week) intervals for 1 year, and every 26 weeks (±4 weeks) until the completion of follow ups. FKSI adds to the FACT-G (27 items) by including 15 items specific to kidney cancer patients. In a HRQOL study focused on patient with mRCC, a symptoms subscale questionnaire was developed and will also be administered in this study.

Health care utilization data needed to assess costs will be obtained from the cost & convenience questionnaire, which includes costs of hospitalization, treatment, ER visits, physician and clinic visits and medications. Markov modeling with probabilistic sensitivity analysis will be used to correlate quality-adjusted survival and cost. Cost-effective analysis (cost & convenience questionnaire) will be given prior to treatment and at the time of progression.