The impact of stereotactic ablative body radiotherapy for primary renal cell carcinoma on renal function

Stereotactic body radiotherapy (SBRT) has emerged as a promising non-invasive treatment option for patients with localized renal cell carcinoma (RCC) who are unsuitable for surgery or other ablative modalities. This study aimed to report the oncological outcomes and toxicity of SBRT for primary RCC in this patient population, with a particular focus on renal function preservation.

This retrospective study included 31 patients who underwent SBRT for primary RCC at a tertiary center between December 2015 and February 2023. Eligible patients were deemed unsuitable for surgery or considered poor candidates for cryotherapy and radiofrequency ablation. The primary outcome was the evolution of renal function over time, assessed by estimated glomerular filtration rate (eGFR). Secondary outcomes included local control, event-free survival, metastasis-free survival, and overall survival.

The median age of the study cohort was 81years, and the median tumor size was 40mm. The most commonly used SBRT dose schedule was 35Gy in five or seven fractions. The median baseline eGFR was 58mL/min, and the median follow-up was 20months. At the last follow-up, the median eGFR was 44mL/min, with a median decrease of 17% compared to baseline. Only two patients with preexisting advanced chronic kidney disease required dialysis. The 3-year end-stage renal disease survival and dialysis-free survival rates were 78% and 84%, respectively.

SBRT is a valuable non-invasive treatment option for localized RCC, particularly in patients with significant comorbidities or high surgical risk, while minimizing the risk of renal function deterioration.

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