Early Detection of Cardiovascular Changes After Radiotherapy for Breast Cancer

EARLY-HEART is a multicentre prospective cohort study that will include 250 female primary breast cancer cases aged 40-75 years treated with postoperative radiotherapy (RT) alone after breast-conserving surgery using modern planning-CT based RT technologies and followed for 2 years after RT in one of the 5 participating hospitals. In addition to the standard follow-up, patients will need to give repeated blood samples and will undergo repeated cardiac imaging: * Functional and anatomical cardiac imaging biomarkers will be based on automated 2D-speckle-tracking echocardiography (ECHO-ST); Computed Tomography Coronary Angiography (CT) and cardiac magnetic resonance imaging (MRI). * Circulating biomarkers (BLOOD) will be based on a panel of multiple classical or novel blood-based biomarkers. Imaging and circulating biomarkers measurements will be assessed at baseline before RT (ECHO, CT, MRI, BLOOD); at the end of RT (BLOOD); 6 months after RT (ECHO, MRI, BLOOD) and 24 months after RT (ECHO, CT, MRI, BLOOD). Changes in functional and anatomical cardiac imaging and circulating biomarkers between unexposed status before RT and exposed status after RT at different time points will be first analysed to evaluate the effects of RT on the heart. All relevant DICOM-data (including planning-CT scans and the ECHO, MRI and CT) will be centralized to the MEDIRAD-ENACT database managed by University of Groningen for automated segmentation of all cardiac substructures (including coronary arteries) to ensure uniformity of the segmentation procedure between centres. The RT planning CTs will be used to generate dose volume histograms and 3D dose maps of the heart and cardiac substructures in order to correlate the localization of any cardiovascular change with the anatomical dose distribution. In the presence of a cardiac outcome, a multimetric Normal Tissue Complication Probability (NTCP) individual risk model will be constructed and an integrative clinical-biologic risk score will be developed for individual risk prediction.