ESTRO 2025 - Abstract Book

S1432

Clinical - Lung

ESTRO 2025

Purpose/Objective: Stereotactic body radiation therapy (SBRT) is a consolidated, safe and valid therapeutic option for patients affected by early stage non-small cell lung cancer (NSCLC) ineligible for surgery approach due to clinical condition (comorbidities and/or elderly patients) or poor respiratory function. Our objective was to evaluate clinical outcomes of pulmonary stereotactic body radiation therapy (SBRT) in patients with chronic obstructive pulmonary disease (COPD). Material/Methods: We retrospectively reviewed medical records of 28 patients diagnosed with COPD who underwent pulmonary SBRT treatment for primary lung tumor or single pulmonary disease recurrence (30%) between January 2021 and February 2024. Baseline patients’ characteristics were as follows: the median age was 74,5 years (62-88 ys); median follow-up was 20 months (6-42 mth). 19 patients were male; 20 pts had adenocarcinoma as tumor histology, 6 were squamous cell carcinoma, 1 was poor-differentiated lung cancer and the other was without biopsy. All patients were affected by COPD and treated with inhaled bronchodilators. Median pulmonary lung function at baseline was FEV1 65% and DLCO 66%. Results: Most of the patients (79%) did not experienced radiotoxicity, while 13.8% and 6.9% exhibited grade I and grade II radiotoxicity, respectively. Five patients experienced COPD exacerbation requiring hospital admission between 3- and 6-months post-treatment, and all of them had history of respiratory infection requiring antibiotic therapy within one month prior to treatment but clinically free of active infection at radiotherapy evaluation (Fisher’s exact test p = <0.001). Home oxygen therapy was used by 23% of patients prior to treatment (0.5 – 2 L/min at rest), with no significant increase during the 12-month follow-up period, (Wilcoxon signed-rank test p = 0.525). The overall progression free survival (PFS) rate at 18 months was 65%. For patients who were initially treated for disease recurrence, the second PFS (PFS2) was 8.5 months (log-rank test p = 0.045). The overall survival (OS) rate at 24 months was 79.5%. In our data, the presence of radiotoxicity at three months did not show a statistically significant association with COPD exacerbation. Conclusion: Pulmonary SBRT is safe; it provides effective local control and does not worsen COPD. Close monitoring is recommended during the 3-6 months post-treatment period in patients with history of respiratory infection with the aim of preventing COPD exacerbations.

Keywords: SBRT, COPD, elderly

4252

Digital Poster Evaluation of automated treatment planning for volumetric modulated arc therapy in stereotactic body lung radiotherapy

Chin Loon Ong, Matthijs Hans, Kelly Hunnego, Eric Franken Radiotherapy, HagaZiekenhuis, The Hague, Netherlands

Purpose/Objective: Treatment planning plays a crucial part in radiotherapy, as the quality of the plan could directly influence treatment’s outcome. With the introduction of advanced technologies, such as volumetric modulated arc therapy and inversed planning, numerous parameters must be considered in generating an optimized clinical plan. Studies have shown variation in treatment plan quality, which can be influenced by planner’s experience(1). The aim of this