While stereotactic ablative body radiotherapy (SABR) is associated with excellent local control for primary renal cell carcinoma (RCC), outcomes based on clear-cell (ccRCC) and non-clear cell (nccRCC) histologies are not well defined.
Individual data of adult patient with biopsy confirmed primary RCC receiving SABR between 2007 and 2021 from 16 institutions in Australia, Canda, Germany, Japan and USA pooled. Patients with metastatic disease or upper tract urothelial carcinoma were excluded. The primary outcome was local failure (LF), based on the Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1. Distant failure (DF), cancer-specific survival (CSS), treatment related toxicity and renal function changes following SABR were defined as secondary outcomes. Kaplan-Meier estimates were generated for LF, DF and CSS stratified by clear cell vs. non-clear cell histology, compared using the log-rank test (CSS) or Gray's test (LF and DF).
Two hundred and eleven patients with a biopsy confirmed ccRCC (n=167) or nccRCC (n=44) were included. In the nccRCC group, 59% (n=26/44) and 11% (n=5/44) were papillary and chromophobe histologies, respectively. Patients with nccRCC were more likely to be older (median age at SABR 77.2 years vs. 71.5, p=0.009) and to be treated with multifraction SABR (82% [n=36/44] vs. 38% [n=63/167]; p < 0.001) than the ccRCC group. The median follow-up was 4.02 years (IQR: 3.43-4.94) and 4.25 years (IQR: 3.02-5.00) for ccRCC and nccRCC groups, respectively. The 5-year cumulative incidence of LF was 1.5% (95% confidence interval [CI]: 0.3-4.8%) in ccRCC group vs. 2.4% (95% CI: 0.2-11.0%) in nccRCC group (hazard ratio [HR]: 0.90, 95% CI: 0.10-8.31, p=0.922). The corresponding cumulative incidence of DF at 5-years was 6.0% in ccRCC group vs. 2.9% in nccRCC group (HR: 0.34, 95% CI: 0.04-2.68, p=0.304). The 5-year estimated CSS was 96.4% in ccRCC group vs. 96.4% in nccRCC group (HR: 2.04, p=0.561). From baseline, eGFR reduced by 11.4 ± 13.4 mL/min at 3 years and by 12.2 ± 14.0 mL/min at 5 years. Sixteen patients (7.6%) experienced grade-2 or higher toxicities, with grade-2 fatigue (5.7%) being the most common.
SABR provides excellent oncologic outcomes, irrespective of ccRCC or nccRCC histology.
International journal of radiation oncology, biology, physics. 2025 Sep 02 [Epub ahead of print]
Muhammad Ali, Rohann J M Correa, David Pryor, Braden Higgs, Swetha Sridharan, Mark Sidhom, Alexander Muacevic, Hiroshi Onishi, Anand Swaminath, William Grubb, Daniel X Yang, Aurelie Grant, Scott C Morgan, Lee Ponsky, Fabio L Cury, Bin S Teh, Simon S Lo, Anand Mahadevan, Irving D Kaplan, William Chu, Raquibul Hannan, Michael Staehler, Nicholas G Zaorsky, Andrew Warner, Alexander V Louie, Shankar Siva
Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia. Electronic address: ., London Health Sciences Centre, London, ON, Canada., Department of Urology and Radiation Oncology, Princess Alexandra Hospital, Woolloongabba, QLD, Australia; Queensland University of Technology, Brisbane, QLD, Australia., Department of Radiation Oncology, Royal Adelaide Hospital, South Australia, Australia; University of South Australia, Adelaide, SA, Australia., Department of Radiation Oncology, Calvary Mater Newcastle, Waratah, NSW, Australia., Department of Radiation Oncology, Liverpool Hospital, Liverpool, NSW, Australia; South West Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia., University of Munich Hospitals, Munich, Germany., Deaprtment of Radiology(,) University of Yamanashi, Yamanashi, Japan., Juravinski Cancer Centre, McMaster University, Hamilton, ON, Canada., Augusta University, Augusta, GA, USA., University of Texas - Southwestern Medical Center, Dallas, TX, USA., The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada., University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA., McGill University Health Centre, Montreal, QC, Canada., Houston Methodist Hospital, Cancer Center and Research Institute, Houston, TX, USA., University of Washington School of Medicine, Fred Hutch Cancer Center, Seattle, WA, USA., NYU Langone Health - Laura and Isaac Perlmutter Cancer Center, New York, NY, USA., Beth Israel Deaconess Medical Center, Boston, MA, USA., Sunnybrook Health Sciences Centre and the University of Toronto, Toronto, ON, Canada., London Health Sciences Centre, London, ON, Canada. Electronic address: ., London Health Sciences Centre, London, ON, Canada; University of Texas - Southwestern Medical Center, Dallas, TX, USA., Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia.