ESTRO 2025 - Abstract Book

S1472

Clinical – Mixed sites & palliation

ESTRO 2025

for spinal metastasis in oligometastatic patients [3,4]. This study aims to evaluate LC, pain control, toxicity rate, and survival outcomes of patients treated with spine SBRT.

Material/Methods: A retrospective study was conducted in oligometastatic patients treated in our department with SBRT for vertebral metastases between 2015 and 2023. Patients with previous neurosurgical interventions were excluded. Vertebral stability was assessed using the Spinal Instability Neoplastic Score (SINS), toxicity graded using the Common Terminology Criteria for Adverse Events v5, and pain based on clinical records. Statistical analysis was performed using SPSS ® . Results: A total of 46 patients were analyzed, with a median follow-up of 21 months (1-78M). The mean age was 63 years and the most frequent primary cancers were breast (34.8%), prostate (30.4%), and lung (19.6%). 73.9% of vertebral metastasis were "stable" (SINS). 63% of patients were treated with 27Gy/3 fractions. The mean gross tumour volume (GTV) was 8.8cc (0.1-48.1cc). At diagnosis, 19 patients reported local pain, and 94.7% of these had some degree of relief: 72.2% partial and 27.7% complete. 21.7% experienced pain flare, 6.5% had compression fractures and none developed radiation myelopathy. 4.3% experienced G1 nausea, dysphagia or odynophagia and 6.5% radiodermatitis. Local progression (LDP) was 4.9% and distant progression (DDP) 48.8%. 30.4% died (10.9% due to DDP). At 12M, progression-free survival (PFS) was 58.1%, LC was 100% (2 LDP events at 14 and 16M), distant PFS (DPFS) was 55%, and overall survival (OS) was 85.7%. SINS was associated with tumour histology (p<0,001). Pain flare correlated with sensory changes after treatment (p=0.015). Compression fractures were not associated with GTV (p=0.793) or SINS (p=0.930). Active primary tumours impacted PFS negatively (HR 3.952, p=0.026). Conclusion: In this study, only two cases of LDP were observed with 100% LC at 12M, consistent with the favourable LC described by the literature (80 – 95% at 12M) [5]. Pain control exceeded the one reported by Guninski et al., likely influenced by our retrospective analysis (94.7% vs. 83.2%) [6]. The rate of compression fractures (6.5%) and the absence of radiation myelopathy are consistent with literature (6-14% and 0.4% respectively) [7-17]. We conclude that SBRT can effectively treat vertebral metastases with good LC, pain control, and low toxicity in oligometastatic patients.

Keywords: SBRT, Spine metastases, Oligometastases

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