Dose-effect Relationship of Kidney Function After Stereotactic Ablative Body Radiotherapy for Primary Renal Cell Carcinoma: Trog 15.03 Fastrack Ii

Mathieu Gaudreault; Nicholas Hardcastle; Price Jackson; Lachlan McIntosh; Braden Higgs; David Pryor; Mark Sidhom; Rachael Dykyj; Alisha Moore; Tomas Kron; Shankar Siva

doi:10.1016/j.ijrobp.2024.04.066

Dose-effect Relationship of Kidney Function After Stereotactic Ablative Body Radiotherapy for Primary Renal Cell Carcinoma: Trog 15.03 Fastrack Ii

Int J Radiat Oncol Biol Phys. 2024 Apr 26:S0360-3016(24)00564-9. doi: 10.1016/j.ijrobp.2024.04.066. Online ahead of print.

Authors

Affiliations

¹ Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia; Sir Peter MacCallum Department of Oncology, the University of Melbourne, Victoria 3000, Australia. Electronic address: mathieu.gaudreault@petermac.org.
² Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia; Sir Peter MacCallum Department of Oncology, the University of Melbourne, Victoria 3000, Australia; Centre for Medical Radiation Physics, University of Wollongong, NSW, 2522, Australia.
³ Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia; Sir Peter MacCallum Department of Oncology, the University of Melbourne, Victoria 3000, Australia.
⁴ Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia.
⁵ Department of Radiation Oncology, Royal Adelaide Hospital, South Australia, Australia; University of South Australia, South Australia, Australia.
⁶ Princess Alexandra Hospital, Queensland, Australia.
⁷ Liverpool Hospital, Liverpool, New South Wales, Australia.
⁸ Trans Tasman Radiation Oncology Group, Waratah, NSW, 2298.
⁹ Sir Peter MacCallum Department of Oncology, the University of Melbourne, Victoria 3000, Australia; Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia.

PMID: 38679212
DOI: 10.1016/j.ijrobp.2024.04.066

Abstract

Background: Stereotactic ablative body radiotherapy (SABR) is a novel option to treat primary renal cell carcinoma (RCC). However, a high radiation dose may be received by the treated kidney, which may affect its function post-treatment. This study investigates the dose-effect relationship of kidney SABR with posttreatment renal function.

Methods: This was a prespecified secondary endpoint of the multicenter FASTRACK II clinical trial (NCT02613819). Patients received either 26 Gy in a single fraction (SF) for tumors with a maximal diameter of 4 cm or less, or 42 Gy in three fractions (multi-fraction (MF)) for larger tumors. To determine renal function change, ^99mTc-DMSA SPECT/CT scans were acquired, and the glomerular filtration rate (GFR) was estimated at baseline, 12-, and 24-months post-treatment. Imaging datasets were rigidly registered to the planning CT where kidneys were segmented to calculate dose-response curves.

Results: From 71 enrolled patients, data from 36 (51%) and 26 (37%) patients were included in this study based on availability of post-treatment data at 12- and 24-months, respectively. The ipsilateral kidney GFR decreased from baseline by 42% and 39% in the SF cohort, and by 45% and 62% in the MF cohort, at 12- and 24-months respectively (p-values < 0.03). The loss in renal function was 3.6±0.8% and 4.5±1.0% in the SF cohort, and 1.7±0.1% and 1.7±0.2% in the MF cohort, at 12- and 24-months respectively. The major loss in renal function occurred in high-dose regions, where dose-response curves converged to a plateau.

Conclusions: For the first time in a multicenter study, the dose-effect relationship at 12- and 24-months post-SABR treatment for primary RCC was quantified. Kidney function reduces linearly with dose up to 100 Gy BED3.

Keywords: GFR, primary renal cell; SABR; dose-effect; kidney; renal function.