ESTRO 2025 - Abstract Book

S1306

Clinical - Lung

ESTRO 2025

Purpose/Objective: Radiation-induced lung injury (RILI) is relatively uncommon but disabling, and a dose-limiting factor in thoracic radiotherapy. This complication is mainly encountered following radiotherapy for lung cancers, and exceptionally for oesophageal, lymphoma or breast cancer. We provide recommendations for good clinical practice, defining the prevention and management of RILI. Material/Methods: Members of the French healthcare and support in oncology association (Association Francophone pour les Soins Oncologiques de Support; AFSOS) and the French society for radiation oncology (Société Française de Radiothérapie Oncologique; SFRO) set up a multidisciplinary working and review group to draft these recommendations for 2023 to 2024, preceded by a systematic review of the literature. Results: RILI comprises several forms, mainly resulting from acute toxicity (radiation pneumonitis) and chronic toxicity (radiation fibrosis). Specific forms can be identified, such as organising pneumonia (formerly bronchiolitis obliterans organizing pneumonia) and radiation recall pneumonia. The risk factors are numerous and include dosimetric risk factors, patient-related factors and tumour-related factors. The incidence of RILI is falling thanks to recent technical innovations, including intensity-modulated radiotherapy, deep inspiration breath hold and stereotactic radiotherapy. New challenges include the specific complications of stereotactic radiotherapy, the combination of recent specific oncological treatments including tyrosine kinase inhibitors and immunotherapy, and the association with certain pathologies such as interstitial lung disease or cardiac comorbidities. Conclusion: The profile of RILI is evolving with new radiotherapy techniques and innovative systemic oncology treatments. Rapid detection and management of these side-effects are essential for good patient care. Digital Poster Impact of Heart and Lung Dosimetry on RV Function in Lung and Oesophageal Cancer Patients Arno C. Hessels 1 , Umut Fidan 1 , Robin Wijsman 1 , Anthonie L. Duijnhouwer 2 , Jan Bussink 3 , Tineke P. Willems 4 , Elke S. Hoendermis 5 , Joost van Melle 5 , Peter van der Meer 5 , Johannes A. Langendijk 1 , Christina T. Muijs 1 , Peter van Luijk 1 1 Radiation Oncology, University Medical Center Groningen, Groningen, Netherlands. 2 Cardiology, Radboud University Medical Center, Nijmegen, Netherlands. 3 Radiation Oncology, Radboud University Medical Center, Nijmegen, Netherlands. 4 Radiology, University Medical Center Groningen, Groningen, Netherlands. 5 Cardiology, University Medical Center Groningen, Groningen, Netherlands Purpose/Objective: Clinically, radiation doses to the heart and lungs impair survival, but the underlying mechanisms remain unclear. Preclinical research has shown that lung irradiation reduces systolic right ventricular (RV) function, while co irradiation of the heart impairs RV recovery with negative impact on survival [1]. This implies that RV dysfunction may explain the link between heart and lung dose and survival. Therefore, we hypothesize that both heart and lung radiation contribute to loss of RV function in patients irradiated for lung and oesophageal cancer. Material/Methods: Data from 209 lung and oesophageal cancer patients who received photon or proton chemoradiotherapy at the UMCG and included in the CLARIFY study (NCT03978377), were analysed. Various aspects of RV function were measured using cardiac ultrasound at baseline, and at 6 weeks, 3 months, 6 months, and 12 months post- Keywords: RILI, SBRT, radiation pneumonitis 897