Stereotactic ablative body radiotherapy (SABR) is an emerging, non-invasive alternative for primary renal cell carcinoma. We aimed to provide the final long-term trial outcomes of TransTasman Radiation Oncology Group (TROG) 15. 03 FASTRACK II, the first phase 2 trial investigating SABR for primary renal cell carcinoma to our knowledge.
FASTRACK II was a non-randomised, phase 2 study conducted in eight hospitals in Australia and the Netherlands by TROG and the Australian and New Zealand Urogenital and Prostate (ANZUP) Cancer Trials Group. Here, we report the final pre-planned follow-up results. Adult patients (aged ≥18 years) with histologically confirmed primary renal cell carcinoma, who were medically inoperable, high risk, or declined surgery, had an Eastern Cooperative Oncology Group performance status of 2 or less, had tumours 10 cm or less in size, and had N0-N1 disease were included. Patients underwent either a single fraction SABR of 26 Gy for tumours 4 cm or less in maximum diameter, or 42 Gy in three fractions delivered 48 h apart for tumours more than 4 cm in maximum diameter. The primary outcome was freedom from local progression to assess local control after SABR evaluated with the Response Evaluation Criteria in Solid Tumours. The primary endpoint and safety were evaluated in the intention-to-treat population. A patient representative was involved in the study design and conduct. The trial was registered with ClinicalTrials.gov (NCT02613819) and is closed to enrolment.
Between July 28, 2016, and Feb 27, 2020, 71 patients were enrolled and one withdrew consent before treatment. Median follow-up was 62 months (IQR 60-72), median age was 77 years (70-82). 49 (70%) of 70 patients were male and 21 (30%) were female. Race and ethnicity data were not collected. The median tumour size was 46 mm (37-55), with 24 (34%) patients with T1a disease, 39 (56%) with T1b disease, six (9%) with T2a disease, and one (1%) with T3a disease. One patient (1%) had nodal involvement (N1). SABR resulted in 100% local control at 36 months, 60 months, and 84 months. Seven (10%) patients had at least one grade 3 adverse event within 9 months of SABR that was designated possibly, probably, or definitely related to treatment: nausea and vomiting (three [4%] events); abdominal, flank, or tumour pain (four [6%]); colonic obstruction (two [3%]); and diarrhoea (one [1%]). No new long-term safety signals, grade 4 events, or treatment-related deaths were noted.
Long-term follow-up supports the safety and local control of SABR for non-surgical patients with renal cell carcinoma, with no observed local recurrences or cancer-related deaths in this cohort, which had predominantly T1b disease or higher.
The Cancer Australia Priority-driven Collaborative Cancer Research Scheme and Varian.
The Lancet. Oncology. 2026 May 17 [Epub ahead of print]
Shankar Siva, David Pryor, Jarad Martin, Nicholas Hardcastle, Daniel Moon, Tomas Kron, Braden Higgs, Farshad Foroudi, Jeremy Ruben, Swetha Sridharan, Rebecca Montgomery, Ryan Davey, Charles Lin, Mark Shaw, Nathan Lawrentschuk, Sree Appu, Ben G L Vanneste, Michael S Hofman, Declan G Murphy, Richard De Abreu Lourenco, Pascal Mancuso, Nicholas R Brook, Avi Raman, Lih-Ming Wong, Mark Sidhom, Simon Wood, Muhammad Ali, Mathias Bressel
Peter MacCallum Cancer Centre, Melbourne, VIC, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, VIC, Australia. Electronic address: ., Princess Alexandra Hospital, Brisbane, QLD, Australia., Calvary Mater Newcastle, Waratah, NSW, Australia., Peter MacCallum Cancer Centre, Melbourne, VIC, Australia., Peter MacCallum Cancer Centre, Melbourne, VIC, Australia; Department of Surgery, University of Melbourne, Melbourne, VIC, Australia., Peter MacCallum Cancer Centre, Melbourne, VIC, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, VIC, Australia; Centre of Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia., Royal Adelaide Hospital, Adelaide, SA, Australia., Monash University, Melbourne, VIC, Australia; Olivia Newton-John Cancer Centre, Melbourne, VIC, Australia., Alfred Health, Melbourne, VIC, Australia., TransTasman Radiation Oncology Group Cancer Research, Newcastle, NSW, Australia., University of Queensland, Brisbane, QLD, Australia; Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia., Peter MacCallum Cancer Centre, Melbourne, VIC, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, VIC, Australia., Cabrini Research Division, Melbourne, VIC, Australia., MAASTRO clinic, Maastricht, Netherlands; Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium., Centre for Health Economics Research and Evaluation, University of Technology Sydney, Sydney, NSW, Australia., Liverpool Hospital, Sydney, NSW, Australia., Royal Adelaide Hospital, Adelaide, SA, Australia; Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia., John Hunter Hospital, Newcastle, NSW, Australia; University of Newcastle, Newcastle, NSW, Australia., Department of Surgery, University of Melbourne, Melbourne, VIC, Australia; Department of Urology, St Vincent's Health, Melbourne, VIC, Australia., Department of Radiation Oncology, Liverpool Cancer Therapy Services, Sydney, NSW, Australia; South West Sydney Clinical School, University of New South Wales, Sydney, NSW Australia.