ESTRO 2025 - Abstract Book

S2057

Clinical - Urology

ESTRO 2025

3556

Proffered Paper SBRT with or without Darolutamide for OligoRecurrent prostate cancer (DART): 6-month quality of life from a randomized phase II trial Renée Bultijnck 1,2 , Piet Dirix 3 , Valérie Fonteyne 2,4 , Ruben De Groote 5 , François-Xavier Otte 6 , Sabine Meersschout 7 , Wim Duthoy 8 , Siska Van Bruwaene 9 , Leen Noé 10 , Michiel Strijbos 11 , Samuel Bral 12 , Hélène Gibson 13 , Joke Tommelein 14 , Dries Loncke 14 , Nancy Vanderstichele 2 , Piet Ost 15,16 1 Department of Human Structure and Repair, Ghent University Hospital, Ghent, Belgium. 2 Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium. 3 Department of Radiation Oncology, Iridium Network, Ghent, Belgium. 4 Department of Human Structure and Repair, Ghent University, Ghent, Belgium. 5 Department of Urology, Onze-Lieve-Vrouwziekenhuis Hospital, Aalst, Belgium. 6 Department of Radiation Oncology, Jules Bordet, Brussels, Belgium. 7 Department of Radiation Oncology, AZ Sint-Jan General Hospital, Bruges, Belgium. 8 Department of Radiation Oncology, AZ Sint-Lucas, Ghent, Belgium. 9 Department of Urology, AZ Groeninge, Kortrijk, Belgium. 10 Department of Radiation Oncology, Jessa Ziekenhuis, Hasselt, Belgium. 11 Department of Medical Oncology, Ziekenhuis aan de Stroom, Wilrijk, Belgium. 12 Department of Radiation Oncology, Onze-Lieve-Vrouwziekenhuis Hospital, Aalst, Belgium. 13 Department of Radiation Oncology, Jules Bordet Institute, Brussels, Belgium. 14 Health, innovation and research institute, Ghent University Hospital, Ghent, Belgium. 15 Department of Human Structure and Repair, Ghent University Hospital, Gent, Belgium. 16 Department of Radiation Oncology, Iridium Network, Wilrijk, Belgium Purpose/Objective: The objective of this randomized phase II trial is to compare the efficacy of combining stereotactic body radiotherapy (SBRT) with 24 weeks of darolutamide (DARO) versus SBRT only in patients with PSMA PET-detected oligometastatic recurrent hormone-sensitive prostate cancer (PCa). The primary endpoint is metastasis-free survival. In this report, we present the 24-week health-related quality of life (HRQoL) outcomes for both arms (secondary endpoint). Material/Methods: In this multicenter, non-blinded, phase II trial, PCa patients with a high-risk biochemical recurrence and up to 5 detected distant metastases on PSMA PET-CT, were randomized (1:1) to receive SBRT plus 24 weeks of DARO or SBRT alone. SBRT was delivered in a single fraction of 20Gy or 3 fractions of 10Gy to the planning target volume. DARO 600mg bid was used. HRQoL was assessed using the EORTC QLQ-C30 and PR25 questionnaire, with measurements taken at baseline, 12 and 24 weeks after randomization and 6-monthly thereafter. Mean changes in HRQoL domains are reported descriptively. The trial was approved by the local ethical committees and registered on clinicaltrials.gov (NCT04641078). Results: Between 02/2021 and 08/2023, 124 patients were randomized (SBRT: N= 61; SBRT+DARO: N = 63). Patient baseline characteristics and HRQoL were comparable between arms (table 1). More than 60% of patients had bone metastases on PSMA PET. HRQoL data missingness increased over time at a higher rate in the SBRT arm (table 1). Global health and most QoL subdomains remained stable in both arms over the 24-week period (table 1 and figure 1). However, we did observe a worsening of hormonal symptoms and fatigue in the SBRT+DARO group as compared to baseline, which was not observed in the SBRT arm (Figure 1). Sexual activity scores were low in both arms for the entire duration of the study (table 1).