ESTRO 2025 - Abstract Book

S1473

Clinical – Mixed sites & palliation

ESTRO 2025

848

Digital Poster Multi-institutional retrospective study of treatment of liver lesions with SBRT

Donatella Caivano 1,2 , Donato Pezzulla 3 , Paolo Bonome 3 , Claudia Ricciardi 4 , Paola Zuccoli 5 , Mattia Serio 4 , Alessandro Molinari 5 , Francesca Giannetti 5 , Claudia Menichelli 5 , Vitaliana De Sanctis 4 , Maurizio Valeriani 4 , Alessandro Fanelli 5 , Daniela Musio 2 , Mattia Falchetto Osti 1,4 1 Department of Medical and Surgical Sciences and Translational Medicine, Traslational Medicine and Oncology, , Faculty of Medicine and Psycology, Sapienza University of Rome, Rome, Italy. 2 Department of Radiation Oncology, San Giovanni Addolorata Hospital, Rome, Italy. 3 Radiation Oncology Unit, Gemelli Molise Hospital - Università Cattolica del Sacro Cuore, Campobasso, Italy. 4 Department of Radiation Oncology, Sant’ Andrea Hospital, Sapienza University of Rome, Rome, Italy. 5 Department of Radiation Oncology, Ecomedica Clinical Research Institute (Ergea Group), Empoli, Italy Purpose/Objective: The liver is a common site of cancer metastasis from various primary tumors. SBRT has been shown to provide effective local control and favorable overall survival in patients with oligometastases. The aim of this study was to analyse LC, DMFS, PFS and OS and predictive factors of response in liver lesions as primary and as metastases in patients treated by SBRT. Material/Methods: This is a retrospective and multi-institutional study that analyzes a group of patients treated by SBRT on liver lesions, with a maximum of five metastasis, Karnofsky performance status > 60 and age >18 years. Results: From 2008 to 2023, we evaluated 85 patients with 138 liver lesions. Median age was 64 years. Single fractions were administered in 20% of cases and multiple fractions in 80% of cases. Eight (6%) lesions were from primary disease, 94% of the lesions were metastases, 20% were classified as oligometastatic synchronous, 38% oligorecurrent, 26% oligoprogressive, 10% oligopersistent. The primary most represented was colon rectal cancer (41%). The actuarial LC rates at one and two years were 68.9% and 64.3%, respectively. For UVA, only complete response was a statistically significant positive prognostic factor for LC (p: 0.008), whereas for MVA, only clinical response (p: 0.013) and small volume (p: 0.041) were confirmed as such. The actuarial DMFS rates at one and two years were 25.5% and 12.0%, respectively. For UVA, only age >64 years (p: 0.006) and BED >97Gy (p: 0.028) were statistically significant positive prognostic factors for DMFS, but for MVA, only age was confirmed (p: 0.022). The actuarial PFS rates at one and two years were 21.5% and 11.6%, respectively. Regarding PFS, only a BED > 97Gy (p:0.024) was a statistically significant positive prognostic factor in UVA, and this was confirmed in MVA (p: 0.025). The actuarial OS rates at one and two years were 82.3% and 66.4%, respectively. For OS, no variable was a statistically significant positive prognostic factor in UVA. Only CR achievement showed a trend towards statistical significance (p: 0.052). Conclusion: SBRT is an option for the treatment of liver lesions as primitive or metastatic, with good rates of LC, able to improve the data of progression-free survival and overall survival. Prospective studies are needed to further confirm the benefit of this treatment and the predictive factors of response.

Keywords: liver lesions, SBRT