ESTRO 2025 - Abstract Book

S1544

Clinical – Mixed sites & palliation

ESTRO 2025

Conclusion: SBRT with SIB is a safe and effective treatment for bone metastases, providing excellent local control and prolonged survival, particularly in patients with favorable diagnoses. Both fractionation regimens achieved comparable LC, confirming their flexibility in clinical practice. The findings support the SBRT as a standard approach for oligometastatic bone disease. This work reflects real-world clinical outcomes and confirms the integration of SBRT into advanced oncology care.

Keywords: SBRT, bone metastasis

3060

Digital Poster Personalized SBRT for bone metastases- A phase III randomized multicentric trial (PREST Trial): preliminary analysis on technical feasibility Francesco Cellini 1 , Stefania MAnfrida 2 , Rossella Di Franco 3 , Gilda Abete 2 , Silvia Longo 2 , Alessia Di Rito 4 , Mariangela Massaccesi 2 , Angelo Errico 4 , Luca Nicosia 5 , Tindara Munafò 6 , Maura Campitelli 2 , Ciro Mazzarella 2 , Vincenzo Frascino 2 , Autorino Rosa 2 , Francesco Ciardo 1 , Valeria Masiello 2 , Filippo Alongi 5 , Alice Zamagni 7 , Giambattista Siepe 7 , Costanza Donati 7 , Salvatore Parisi 6 , Alessio Giuseppe Morganti 7 , Matteo Muto 3 , Paolo Muto 3 , Maria Antonietta Gambacorta 1 1 Dipartimento Universitario Diagnostica per immagini, Radioterapia Oncologica ed Ematologia, Università Cattolica del Sacro Cuore, Rome, Italy. 2 Dipartimento di Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Rome, Italy. 3 Department of Radiation Oncology, Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, Italy. 4 UOC Radioterapia, Ospedale Mons Dimiccoli, Barletta, Italy. 5 Advanced Radiation Oncology department, IRCCS Sacro Cuore don Calabria Hospital, Negrar di Valpolicella, Italy. 6 Unit of Radiation Therapy, IRCCS "Casa Sollievo della Sofferenza", San Giovanni Rotondo, Italy. 7 Radiation Oncology, IRCCS Azienda Ospedaliero - Universitaria di Bologna, Bologna, Italy Purpose/Objective: Palliative Radiotherapy (PRT) for painful bone metastases represents a clinical and scientific issue. Intensified SBRT is often applied but clear evaluation of result is difficult since most experiences are outside clinical trials. In most of the studies a prognostic score to stratify patients is not applied, although usually suggested as needed. Only 8 Phase 3 trial are available as full publication, with controversial results. The PREST trial is a multicentric Phase 3 trial facing standard PRT versus SBRT for patients selected by prognostic score [REF 1]. Aim of this preliminary evaluation is to weight its technical feasibility . (Clinicaltrial.gov identifier: 0013663/18) Material/Methods: In PREST trial, patients with painful spinal metastases (stratified by a validated prognostic score selecting patients at better prognosis - Mizumoto Score [REF 2]) are either randomized to conventional PRT delivering 20 Gy in 5 fractions or to SBRT by SIB (21 Gy in 3 fraction of 7 Gy to the entire vertebral body+30 Gy in 3 fraction of 10 Gy to the GTV). The experimental arm requires one or more CBCT at each session. Primary endpoint is palliative effect on the CTV at 3 months, according to International Chow’s criteria (thus, not only according the NRS response). We collected technical IGRT characteristics (linear and angular errors and number of required CBCT) and toxicity of the first 10 patients enrolled in SBRT arm, to check feasibility. Only the first 10 patients progressively enrolled in experimental arm were considered for this analysis. Results: Global trial enrollment started on 2020. Mean number of CBCT per daily fraction was 1,8. Median displacement for set-up (in cm) accounted for: 0.2835 Vertical, 0.088 Longitudinal, 0.263 Lateral. Median angular set-up error (in degrees) accounted for: 0.516 Pitch, 0.1635 Roll, 0.166 Rtn. Current median follow-up is 6 months (range 3-26 months) - enrollment ongoing-. All patients completed each SBRT session with full compliance. No toxicity of CTCAE Grade >3 was reported at 1 and 3 months.