Top Line: SABR is likely underutilized in the treatment of early stage, inoperable renal cell carcinoma due to limited prospective data.
The Study: In this prospective phase 2 trial, 16 patients with RCC measuring 5cm or less were treated with primary SABR. All patients had biopsy confirmed tumors that were growing on surveillance imaging. They received either 36 Gy in 3 fractions (63%) or 40 Gy in 5 fractions (27%). At 1 year, the rate of radiographic local control was 94% with 19% of patients having radiographic response. Biopsies at 1 year confirmed histologic evidence of tumor response, hyalinization, and decreased Ki67. Qualitatively, responses were more common among patients treated with the 3 fraction regimen. Ultimately, 2 patients developed local failure after initial control. Treatment related toxicity was very mild with no grade 2 or higher events. While eGFR significantly declined post-treatment (mean 10.2 ml/min), the rate of decline was not significantly different from the patients’ annualized rate of decline prior to treatment.
TBL This small phase 2 trial adds to the body of prospective data showing that SABR is a safe and effective treatment strategy for inoperable RCC. | Hannan, Eur Urol 2023
The Study: In this prospective phase 2 trial, 16 patients with RCC measuring 5cm or less were treated with primary SABR. All patients had biopsy confirmed tumors that were growing on surveillance imaging. They received either 36 Gy in 3 fractions (63%) or 40 Gy in 5 fractions (27%). At 1 year, the rate of radiographic local control was 94% with 19% of patients having radiographic response. Biopsies at 1 year confirmed histologic evidence of tumor response, hyalinization, and decreased Ki67. Qualitatively, responses were more common among patients treated with the 3 fraction regimen. Ultimately, 2 patients developed local failure after initial control. Treatment related toxicity was very mild with no grade 2 or higher events. While eGFR significantly declined post-treatment (mean 10.2 ml/min), the rate of decline was not significantly different from the patients’ annualized rate of decline prior to treatment.
TBL This small phase 2 trial adds to the body of prospective data showing that SABR is a safe and effective treatment strategy for inoperable RCC. | Hannan, Eur Urol 2023