Franziska Nägler, Sebastian Schäfer, Isabell Seiler, Camilla von Wachter, Panagiotis Balermpas, Mauro Loi, Pierluigi Bonomo, Marek Slávik, Petr Burkon, Lena Kästner, Johannes Meents, Fabian Lohaus, Jochen Willner, Anna Sabrina Schunn, Sophia Drabke, Kenneth Klischies, Olaf Wittenstein, Priska Bank, Richard Partl, Jörg Andreas Müller, Ahmed Gawish, Arne Grün, Andrea Baehr, Maike Trommer, Eleni Gkika, Thomas Mader, Richard Holý, Bernd Frerker, Felix Ehret, Alexander Rühle, Matthias Guckenberger, Christos Moustakis, Thomas B. Brunner, Oliver Blanck, Judit Boda-Heggemann, Nils H. Nicolay
INTRODUCTION: Outcome patterns for stereotactic body radiotherapy (SBRT) of bone oligometastases (BoM) especially for older patients are inadequately defined. We aimed to evaluate oncological outcomes and tolerability of SBRT for BoM in older patients. MATERIAL AND METHODS: Patients ≥70 years treated with SBRT for BoM between 2010 and 2024 at 20 European centers were analyzed and compared to patients <70 years. Outcomes included local recurrence (LR)/ freedom from LR (FFLR), progression-free survival (PFS), overall survival (OS), and adverse events. RESULTS: 789 patients with 1079 BoM were analyzed. Median age was 68 years (range: 19-91), and 355 patients (45.0%) were ≥70 years. Most common primary tumors were prostate (57.4%), breast (13.8%), and lung cancers (10.5%). LR at 3 years was 9.3% (CI: 6.0-12.8%) in patients <70 years and 11.7% (CI: 7.1-16.8%) in patients ≥70 years (p = 0.39). Grade-3 adverse events occurred in 1.8% of patients <70 years and 1.4% ≥70 years. No grade-4/5 adverse events were observed. Fracture rates were 2.9% for patients <70 years, and 1.8% ≥70 years. A higher metastatic volume was associated with reduced FFLR (Hazard ratio [HR] 1.006; p = 0.02), PFS (HR 1.003; p = 0.05), and OS (HR 1.003; p = 0.04). A better performance status was related to improved PFS (HR 0.98; p < 0.01) and OS (HR 0.96; p < 0.001), while age was not a significant factor. CONCLUSION: This multicenter cohort analysis showed that SBRT of BoM is effective and well tolerated even in older patients. There were no significant differences in outcomes or side effects including fracture rates across patient age groups.