Enthusiasm continues to build for the use of stereotactic ablative radiotherapy (SABR) for primary renal cell carcinoma (RCC), with evidence including several prospective clinical trials demonstrating excellent oncologic and renal function outcomes. In this issue of European Urology, Hannan and colleagues [] add to the rising tide of prospective evidence and provide novel post-treatment histology data on the nuances of cellular and transcriptomic changes after SABR.