ESTRO 2024 - Abstract Book

S1626

Clinical - Lung

ESTRO 2024

Netherlands. 4 University Medical Center Groningen, Radiology, Groningen, Netherlands. 5 University Medical Center Groningen, Cardiology, Groningen, Netherlands

Purpose/Objective:

Despite technological improvements, thoracic radiotherapy is still associated with side-effects, such as cardiotoxicity. Indeed, various studies suggest that thoracic radiotherapy leads to cardiac damage and that dose to the heart is even associated with overall survival. In preclinical studies, histopathological cardiac and pulmonary changes have been identified that lead to changes in both left and right-ventricle function and morphology already in the first weeks after irradiation. Therefore, the CLARIFY-study was initiated to test the hypothesis that such early changes also occur in patients, and to assess if these changes have clinical impact. In a previous interim analysis, we demonstrated that thoracic radiotherapy can cause reductions in right ventricle function in association with irradiated lung volume (1). The aim of the present interim analysis of the CLARIFY-study was to investigate if thoracic radiotherapy can cause changes in left ventricular function in patients treated for lung or oesophageal cancer and to identify patient and treatment related risk factors for such changes.

Material/Methods:

The study population of this interim analysis was composed of 171 patients included in the prospective observational CLARIFY-study in our centre between September 2018 and September 2023 (Table 1). Left ventricular global longitudinal strain (LV-GLS) is a sensitive parameter to detect subclinical LV dysfunction. Therefore LV-GLS was assessed using echocardiography at baseline, at 6 weeks, 6 months and one year after radiotherapy. To classify LV- GLS as “subclinical LV dysfunction”, we used the commonly -used criterion of a relative reduction of at least 15% compared with baseline. Statistical significance of changes was assessed with repeated measures ANOVA. The influence of patient and treatment related factors on post-treatment LV-GLS was assessed using linear regression analysis. Differences in mean heart dose (MHD) between treatment types were tested using the t-test.