S789
Clinical - Lung
ESTRO 2026
included (Table 1). NSCLC presentation was locally advanced not-suitable for definitive radio- chemotherapy and metastatic in 21 (48.8%) and 22 (51.2%) cases, respectively. ICIs were PD-1 inhibitors in 38 (88.4%) patients, administered for a median of 6 cycles (range 1-31) prior to CTRT. Radical and subradical CTRT was administered in 22 (51.2%) and 21 (48.8%) patients, respectively, at a median Equivalent Dose in 2 Gy Fractions (EQD2) of 50.0 Gy (59.2 Gy and 48.8 Gy for radical and subradical CTRT respectively).
1. Gouw ZAR, Jeong J, Rimner A, Lee NY, Jackson A, Fu A, et al. "Primer shot" fractionation with an early treatment break is theoretically superior to consecutive weekday fractionation schemes for early- stage non-small cell lung cancer. Radiother Oncol. 2023:110006.2. Menegakis A, Vennin C, Ient J, Groot AJ, Krenning L, Klompmaker R, et al. A novel lineage-tracing tool reveals that hypoxic tumor cells drive tumor relapse after radiotherapy. Radiotherapy and Oncology. 2025;202:110592. Keywords: NSCLC, hypoxia, feasibility High-dose consolidative thoracic radiotherapy in advanced NSCLC with favorable response after first-line systemic therapy with ICIs Marco Galaverni 1 , Federico Colombo 1 , Cristina Dell'Anna 1 , Elisabetta Lattanzi 1 , Claudia Grondelli 1 , Francesco Salaroli 1 , Ilaria Renna 1 , Maria Luisa Bergamini 1 , Giovanni Ceccon 1 , Stella Gianni 1 , Maria Majori 2 , Nicola Sverzellati 3 , Alessandro Leonetti 4 , Marcello Tiseo 4 , Patrizia Ciammella 5 , Alessio Bruni 6 , Nunziata D'Abbiero 1 , Nicola Simoni 1 1 Department of Radiation Oncology and Radiosurgery, University Hospital of Parma, Parma, Italy. 2 Pulmonology and Thoracic Endoscopy Unit, University Hospital of Parma, Parma, Italy. 3 Medicine and Surgery (DiMeC), University of Parma, Parma, Italy. 4 Medical Oncology Unit, University Hospital of Parma, Parma, Italy. 5 Radiotherapy Unit, AUSL-IRCCS di Reggio Emilia, Reggio Emilia, Italy. 6 Radiotherapy Unit, University Hospital of Modena, Modena, Italy Purpose/Objective: Consolidative thoracic radiotherapy (CTRT) improved oncological outcomes in patients with advanced and metastatic non-small-cell lung cancer (NSCLC) with favorable response after first-line chemotherapy (CT). However, clinical benefit and potential side effects of high-dose CTRT in patients treated with prior immune checkpoint inhibitors (ICIs) are yet to be defined. This study aims to investigate clinical results of CTRT in patients with NSCLC and previously treated with (CT- )ICIs. Material/Methods: Poster Discussion 2343 Patients treated at two Institutions with CTRT after first-line systemic treatment with (CT-)ICIs were retrospectively analyzed. Local failurefree survival (LFFS), progressionfree survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier method. Pulmonary adverse events following CTRT were graded per Common Terminology Criteria for Adverse Events (CTCAE). Results: A total of 43 patients treated from 2019 to 2024 were
At a median estimated follow-up time of 35.7 months (95% CI 28.9-45.3 months), 1- and 3-year LFFS rate was 87.1% (95% CI 77.2-98.3) and 66.4% (95% CI 50.5-87.5), respectively. Median PFS and OS were 19.6 months (95% CI 9.8-NE) and 48.8 months (95% CI 15.5-NE), respectively (Figure 1A). Radiation pneumonitis (RP) G ≥ 2 rate was 27.9%, occurring at a median time of 2.3 months (range 0.8-6.0) from CTRT, with G3 and G5 RP observed in 5 (11.6%) and 1 (2.3%) patients, respectively. Acute RP G ≥ 2 occurrence correlated with number of pre-CTRT ICIs cycles (9.5 % ≤ 6 cycles vs 40.0% ≥ 7 cycles, p = .03) (Figure 1B), but not with CTRT prescribed dose (27.3% radical vs 28.6% subradical, p = .92). Considering all pulmonary side effects (radiation-induced, ICI-induced, infectious, and/or multifactorial pneumonitis), G ≥ 2 rate was 32.6%, with G3 and G5 events observed in 18.6% and 7.0% of patients, respectively.
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