ESTRO 2025 - Abstract Book

S1428

Clinical - Lung

ESTRO 2025

Larger cohorts and more robust prospective studies are needed to clarify the role of CS doses in this setting, particularly in new attempts to escalate RT dose.

Keywords: NSCLC, heart, RT

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Digital Poster THE ROLE OF LUNG METASTASES DIRECTED SBRT IN DELAYING SYSTEMIC THERAPHY PROGRESSION: A SINGLE INSTUTION ANALYSIS Bonelli Rosario 1 , Marco Lucarelli 1 , Giulia de Pasquale 1 , Annamaria Vinciguerra 1 , Antonietta Augurio 1 , Maria Taraborrelli 1 , Consuelo Rosa 1 , Andrea D'Aviero 1,2 , Domenico Genovesi 1,2 1 Department of Radiation Oncology, "S.S. Annunziata" Hospital, Chieti, Italy. 2 Department of Medical, Oral and Biotechnological Sciences, “G. D’Annunzio” University of Chieti, Chieti, Italy Purpose/Objective: The evolution of diagnostic techniques and the efficacy of oncological therapies has allowed the definition of oligoprogressive disease, which is changing the therapeutic landscape of metastatic patients 1 . In this context, local therapies have carved out a relevant role in the treatment of metastatic patients, not only in terms of local control (LC), but especially with an impact on overall survival (OS) and progression-free survival (PFS). Such treatments also allow delaying the change to systemic therapies in patients with partial response on the burden of metastatic disease defined as PFS 2 providing the opportunity to maximize the response to pharmacological treatments 2 . Stereotactic Body Radiotherapy (SBRT) allows to safely deliver local treatmets with limited toxicity and high patient compliance. Aim of our experience was to evaluate the impact of SBRT on oligometastatic lung lesions in terms of LC, PFS and OS with a special focus on PFS 2 rates. Material/Methods: A retrospective analysis of patients who underwent SBRT for oligometastatic lung lesions between March 2017 and January 2024 was performed. Patients with up to five progressive lesions were included, reporting overall LC, PFS and OS rates. Mantel-Cox test was performed to identify factors influencing PFS 2 . Results: Data of a total of 25 patients were analyzed. De-novo oliprogression was shown in 36 patients (36%), while the rates following I- II- and III-line systemic therapy where 44%, 16% and 4%respectively. Respiratory motion during the SBRT treatment was managed with 4DCT acquisition for the whole population. The median dose of SBRT was 50 Gy (range 30-55 Gy) with BED10 values ranging from 50 to 115,5 Gy (median 50 Gy). All patients included in the analysis performed routine follow-up evaluations with at least 6 months from SBRT conclusion. Median PFS 2 for the whole population was 14 months (range 2-59 months); the median rates for LC, PFS and OS resulted in 29, 13 and 31 months respectively. The presence of only one oligometastatic lesion ( p=0.0029 ) and only one oligometastatic lung lesion ( p=0.001 ) resulted to be statistically significant for PFS 2 .