(UroToday.com) At ASCO GU 2026, Dr. Giulio Francolini presented the long-term overall survival (OS) and prostate cancer–specific survival (PCSS) results from the ARTO trial (NCT03449719), a randomized phase II study evaluating the addition of stereotactic body radiotherapy (SBRT) to abiraterone acetate in first-line oligometastatic castration-resistant prostate cancer (omCRPC).
ARTO is a randomized phase II trial testing the benefit of SBRT addition to abiraterone acetate in first-line oligometastatic CRPC (omCRPC). The trial was previously positive for biochemical and radiological progression-free survival (PFS).1 The current report presents an updated and comprehensive evaluation of OS and PCSS.
A total of 157 patients with omCRPC were randomized 1:1 to receive abiraterone acetate ± SBRT delivered to all sites of disease. No previous treatment for mCRPC was allowed.
Cox regression analysis was performed to compare:
- Biochemical progression-free survival (bPFS)
- Radiological progression-free survival (rPFS)
- OS
- PCSS
At a median follow-up of 53 months (IQR 43–60), previously reported benefits in bPFS and rPFS were confirmed in favor of the experimental arm:
- bPFS: HR 0.49 (95% CI 0.33–0.73), p<0.001
- rPFS: HR 0.48 (95% CI 0.32–0.72), p<0.001
Importantly, significant survival benefits were also observed:
- OS: HR 0.55 (95% CI 0.33–0.92)
- PCSS: HR 0.37 (95% CI 0.18–0.78)
These hazard ratios indicate a 45% relative reduction in risk of death overall and a 63% relative reduction in prostate cancer–specific mortality with the addition of SBRT.
Dr. Francolini concluded as follows:
- Significant OS and PCSS benefit was detected in patients undergoing concomitant SBRT + abiraterone. These results warrant confirmation in phase III trials.
- The ARTO trial provides some of the strongest long-term randomized evidence supporting metastasis-directed radiotherapy in the oligometastatic CRPC setting
Presented by: Giulio Francolini, MD, Radiation Oncologist, Radiation Oncology Unit, Azienda Ospedaliero Universitaria Careggi, Florence, Italy
Written by: Rashid K. Sayyid, MD, MSc, Assistant Professor, Urologic Oncologist, Department of Urology at The University of Arizona and Banner University Medical Center, Tucson, AZ – @rksayyid on X during the 2026 American Society of Clinical Oncology Genitourinary (ASCO GU) cancers symposium held in San Francisco, CA, between February 26th and 28th, 2026.
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