ESTRO 2024 - Abstract Book

S2891

Interdiscplinary - Other

ESTRO 2024

683

Poster Discussion

Patterns of CT lung injury after SABR for primary or secondary lung lesions

Maria Belmonte 1,2 , Laura Giannini 1,2 , Chiara Chissotti 1,2 , Sara Trivellato 3 , Valeria Faccenda 3 , Paolo Caricato 3 , Sofia Paola Bianchi 1,2 , Federica Ferrario 1,2 , Saufi Sara 1,2 , Gaia Parma 1,2 , Denis Panizza 3 , Stefano Arcangeli 1,2 1 IRCCS Foundation San Gerardo dei Tintori, Department of Radiation Oncology, Monza, Italy. 2 School of Medicine and Surgery, University of Milan Bicocca, Monza, Italy. 3 IRCCS Foundation San Gerardo dei Tintori Monza, Medical Physics Department, Monza, Italy

Purpose/Objective:

Radiological lung density changes are commonly observed in the majority of patients undergoing stereotactic ablative radiotherapy (SABR). This study aims to evaluate possible correlations between clinical/dosimetric variables and acute and long-term radiation-induced lung changes in terms of radiological findings observed at CT.

Material/Methods:

A mono-institutional cohort of SABR patients treated between 2016 and 2022 has been retrospectively analyzed. Eligible patients with primary or secondary lung lesions were treated on a Linac platform with a VMAT technique to median dose of 50 Gy (range 45-60 Gy), corresponding to a BED 10 ≥100 Gy. Pre-treatment and follow-up CT have been retrieved and evaluated. Follow-up CT scans were examined at three different timepoints: 0-6 months (early-term), 6-12 months (mid-term) and over 12 months (long-term). Radiation-induced lung injuries were evaluated according to Ikezoe (within 6 months) and Koening (> 6 months) classification, respectively. Univariate analysis was performed to correlate different radiological patterns to clinical features, reported in Table 1, and dosimetric parameters (e.g. treatment schedule, mean dose to the PTV, lung V10 and V5).