ESTRO 2025 - Abstract Book

S1596

Clinical – Mixed sites & palliation

ESTRO 2025

Conclusion: PT ReRT using hypofractionation schedules showed to be feasible and safe. Longer follow up is required to define efficacy along with the long-term side effects.

Keywords: hypofractionated PT, re-RT

4379

Digital Poster Stereotactic Radiosurgery for Extracranial Oligometastatic Patients: Preliminary Results from a Prospective Observational Study Marco Galaverni 1 , Federico Colombo 1 , Cristina Dell'Anna 1 , Claudia Grondelli 1 , Francesco Salaroli 1 , Ilaria Renna 1 , Maria Luisa Bergamini 1 , Giovanni Ceccon 1 , Elisabetta Lattanzi 1 , Stella Gianni 1 , Caterina Ghetti 2 , Nicola Sverzellati 3 , Livia Ruffini 4 , Nunziata D'Abbiero 1 , Nicola Simoni 1 1 Radiation Oncology Unit, University Hospital of Parma, Parma, Italy. 2 Medical Physics Unit, University Hospital of Parma, Parma, Italy. 3 Department of Medicine and Surgery (DiMeC), University of Parma, Parma, Italy. 4 Nuclear Medicine Division, University Hospital of Parma, Parma, Italy

Purpose/Objective: To report preliminary data from a prospective observational clinical study (SONIC-O) assessing the use of stereotactic radiosurgery (SRS) in extracranial oligometastatic patients (OMPs).

Material/Methods: Oligometastatic patients, according to ESTRO-EORTC criteria, treated at our Institution with SRS between January 2023 and June 2024 were analyzed. Eligible patients had oligometastatic disease (1 to 5 lesions) from solid-organ malignancies. Exclusion criteria were central/ultracentral pulmonary lesions, metastases located < 5 mm from spinal cord and/or any hollow gastro-intestinal structure, and/or > 5 cm in largest diameter. The primary endpoints were treatment- related toxicity (CTCAE G≥3) and local control (LC). Secondary objectives included progression -free survival (PFS), freedom from next systemic therapy (fNST), freedom from polymetastatic disease (fPMD), and overall survival (OS).

Results: In total, 70 OMPs accounting for 102 lesions received SRS (table 1).