Primary Renal Cancer

The purpose of this study is to investigate the use of an MR-guided linear accelerator to treat early stage renal cancer patients, considered inoperable or in patients declining surgerys. The study will collect efficacy, toxicity, and dosimetry data and assess the degree of improvement provided by this treatment technique. The primary objective is to evaluate whether magnetic resonance imaging (MRI)-guided radiation therapy (MRgRT) for primary renal cancer has an improved toxicity profile relative to conventional computed tomography (CT) based radiation therapy, as measured by the frequency of grade 2+ adverse events following MRgRT as per Common Terminology Criteria for Adverse Events (CTCAE) version 6.0.