S756
Clinical - Lung
ESTRO 2026
Keywords: Mesothelioma, AI, ChatGPT, Gemini
potential confounding. Results:
From a database of 410 patients, 101 patients were available for analysis; with a median follow-up of 10 years, 30 patients experienced 40 events corresponding to the primary outcome. The most common event was HF (n=12), followed by atrial fibrillation (n=9), coronary artery disease (n=9), stroke (n=6), valve placement (n=2), pacemaker insertion (n=2). Mean left ventricular dose above the cohort median (14.8 Gy) was associated with significantly higher risk of HF (OR 0.17, 95% CI 0.05–0.61, p=0.007), with risk increasing by 6% per Gy (95% CI 1–12%, p=0.027). This association remained significant after adjusting for age and comorbidities. No association was found between right heart dose and HF, nor between arterial or nodal dose and ischemia or arrhythmia. Survival at 5, 10, and 15 years was high but was modestly lower among patients with the primary outcome.
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Cardiac Adverse Events Following Post-Operative Radiation Therapy in Patients with Thymomas Oded Icht 1,2 , Inbar Nardi-Agmon 3 , John M Miro 4 , Omar Badran 4 , Keshavjee Shaf 5 , Xiang Y Ye 6 , Tirth Patel 7 , John B Cho 1,2 , Andrea Bezjak 1,2 , Geoffrey Liu 4 , Paaladinesh Thavendiranathan 3 , Iymad Mansour 1,2 , Tony Tadic 1,2 , Andrew Hope 1,2 1 Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada. 2 Department of Radiation Oncology, University of Toronto, Toronto, Canada. 3 Department of Medicine, Division of Cardiology, Ted Rogers Program in Cardiotoxicity Prevention, Peter Munk Cardiac Center, Toronto General Hospital, Toronto, Canada. 4 Department of Medical Oncology, Princess Margaret Cancer Centre, Toronto, Canada. 5 Division of Thoracic Surgery, Toronto General Hospital, Toronto, Canada. 6 Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, Canada. 7 Techna Institute, University Health Network, Toronto, Canada Purpose/Objective: Radiation therapy (RT) for thymic malignancies often exposes cardiac structures to ionizing radiation with associated long-term cardiac adverse events risk [1]. Given the curative intent and prolonged survival typical of thymoma patients [2], identifying potentially modifiable predictors of cardiac risk is essential. While cardiac substructure dosimetry has been studied in other thoracic cancers [3], its relevance in thymoma- where target volumes frequently abut or overlap the heart-remains poorly characterized. The objective of this study was to evaluate the relationship between radiation dose to individual cardiac substructures and the subsequent risk of major cardiac events in thymoma survivors treated with surgery and postoperative RT. Material/Methods: We retrospectively identified patients treated with surgery and postoperative RT for thymic malignancies between 2004–2021 with treatment planning information available. Cardiac substructures were automatically segmented using an open-source tool [4], and dose–volume metrics were extracted for 18 individual cardiac regions. The primary outcome was a composite of heart failure (HF), coronary artery disease, arrhythmias, valve disease, stroke, and pacemaker insertion. Associations between substructure dose and the primary outcome were assessed using logistic regression. Both univariate and multivariable analyses were performed, adjusting for baseline cardiac risk factors and age to account for
Conclusion: Higher radiation dose to the left ventricle was independently associated with increased risk of late HF in thymoma survivors. These findings support incorporating substructure-based cardiac dose guidance - particularly left ventricular dose limits-into treatment planning for thymoma, and highlight the need for long-term cardiac surveillance in this
population. References:
1. Li X, Wu Y, Wang Q, Li B, Wang J. Radiation-induced cardiac substructure damage and dose constraints: a review. Radiat Oncol. 2025;20(1):94. Published 2025 Jun 5. doi:10.1186/s13014-025-02668-x 2. Simone CB II. State of the art in radiation therapy for thymic
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