MRI-Guided Radiation Therapy for the Treatment of Early-Stage Kidney Cancer, the MRI-MARK Trial

PRIMARY OBJECTIVE: I. To evaluate local control following magnetic resonance imaging (MRI)-guided stereotactic body radiation therapy (SBRT) for primary kidney cancer as defined by no growth by imaging at 24 months following SBRT. SECONDARY OBJECTIVES: I. To estimate preservation of renal function and to determine frequency of grade 3+ adverse events following SBRT as per Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. II. To characterize tumor and treated kidney changes by multiparametric MRI, including utility of diffusion and perfusion changes in renal cell carcinoma (RCC) prior to and after SBRT as biomarkers of treatment response. III. To estimate the rate of pathologic complete response as determined by tumor biopsy at 24 months following SBRT. IV. To estimate rate of no progression by Response Evaluation Criteria in Solid Tumors (RECIST) at 24 months (less than 20% growth in largest tumor dimension as measured by imaging). V. To estimate the rates of overall survival and distant metastasis. VI. To evaluate economic strain following SBRT for primary kidney cancer. VII. Compare planned total doses to true total doses delivered to the target and adjacent normal structures, to correlate true delivered doses to normal structures to grade 3+ toxicity, and to determine the rate of cases in which the prescribed isodose line failed to cover 100% of the internal gross tumor volume (iGTV). OUTLINE: Patients undergo an MRI scan to check the status and location of the disease, including the motion of the tumor during breathing. Two weeks after MRI, patients undergo SBRT over 1-2 hours on 3 non-consecutive weekdays in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 3, 6, 12, 18, and 24 months, then every 6 months thereafter until the end of the study.