The ARTO trial showed improved early clinical outcomes by adding metastasis-directed therapy (MDT), through stereotactic body radiotherapy (SBRT), to abiraterone acetate and ADT in oligometastatic castrate-resistant prostate cancer. The aim of this analysis is to explore the long-term impact of MDT on overall survival.
ARTO was a multicentre, phase 2, randomised trial conducted in 16 academic and community centres across Italy. All patients included were aged 18 years or older and had a diagnosis of prostate adenocarcinoma with metastatic castrate-resistant prostate cancer, no more than three metastatic sites, and no previous systemic therapy for metastatic castrate-resistant prostate cancer status. Patients were randomly assigned (1:1, using random permuted blocks; stratified by treating centre, Eastern Cooperative Oncology Group performance status, and number of metastases) in an open-label design to androgen deprivation therapy plus oral abiraterone acetate 1000 mg daily with or without SBRT to all sites of metastatic disease (one to five fractions providing a biologically effective dose ≥100 Gy). The primary endpoint was 6-month biochemical response (PSA decrease of ≥50% compared with baseline) and has been reported previously. After meeting its primary endpoint, the power calculation was updated post-hoc to assess overall survival, finalised before data unmasking. We present an unplanned long-term follow-up focusing on overall survival. All analyses were performed on an intention-to-treat basis. The trial is registered on ClinicalTrials.gov (NCT03449719) and is now closed.
Between Jan 2, 2019, and Sept 7, 2022, 157 patients were randomly assigned to the control (n=82) and experimental (n=75) groups. No data about race or ethnicity were collected. After a median follow up of 53 months (IQR 43-60), median overall survival was 50 months (95% CI 36-not reached [NR]) in the control group versus NR (55-NR) in the experimental group (HR 0·55, 95% CI 0·33-0·92, p=0·021). Most common grade 3-4 adverse events recorded were infectious complications (five in the control group vs zero in the experimental group) and cardiovascular disorders (three in the control group vs three in the experimental group). One treatment-related death occurred in the control group due to myocardial failure.
The ARTO trial showed significant benefit in overall survival with the addition of MDT to systemic therapy versus systemic therapy alone.
Fondazione Radioterapia Oncologica.
The Lancet. Oncology. 2026 Jul [Epub]
Giulio Francolini, Vanessa Di Cataldo, Saverio Caini, Pietro Garlatti, Michele Aquilano, Niccolò Bertini, Alessio Bruni, Gianluca Ingrosso, Rolando M D'Angelillo, Luca Tagliaferri, Barbara A Jereczek-Fossa, Matteo Augugliaro, Luca Triggiani, Silvana Parisi, Lorenzo Masieri, Riccardo Campi, Richard K Valicenti, Gabriele Simontacchi, Daniela Greto, Pierluigi Bonomo, Mauro Loi, Chad Tang, Lorenzo Livi, ARTO Working Group
Radiation Oncology Unit, Oncology Department, Azienda Ospedaliero Universitaria Careggi, Florence, Italy. Electronic address: ., Radiation Oncology Unit, Oncology Department, Azienda Ospedaliero Universitaria Careggi, Florence, Italy., Cancer Risk Factors and Lifestyle Epidemiology Unit, Institute for Cancer Research, Prevention and Clinical Network, Florence, Italy., Radiation Oncology Unit, Department of Medical and Surgical Sciences for Children & Adults, University of Modena and Reggio Emilia, Modena, Italy., Radiation Oncology Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy., Radiation Oncology, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy., UOC Degenze di Radioterapia Oncologica, Dipartimento di Diagnostica per Immagini e Radioterapia Oncologica, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze Radiologiche ed Ematologiche, Università Cattolica del Sacro Cuore, Rome, Italy., Department of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy; Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy., Unit of Radiotherapy, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy., Department of Radiation Oncology, Università degli studi di Brescia, Brescia, Italy., Radiation Oncology Unit, Department of Biomedical, Dental Science and Morphological and Functional Images, University of Messina, Messina, Italy., Unit of Urology and Renal Transplantation Oncology Department, Careggi University Hospital, Florence, Italy; Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy., Department of Radiation Oncology, UC Davis, Davis, CA, USA., Department of Genitourinary Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.