Abstract
PURPOSE: Our objective was to characterize the early changes in cardiac function after thoracic radiation therapy (RT) using 3D echocardiography. METHODS AND MATERIALS: In a prospective longitudinal cohort study of 69 patients with breast cancer, lung cancer, or mediastinal lymphoma treated with chemotherapy and RT, clinical and 3D echocardiographic data were assessed before, immediately after, and 5 to 9 months after RT completion. 3D left ventricular ejection fraction, global circumferential strain, global longitudinal strain (GLS), average 3D strain, twist, and torsion were quantified. Associations among mean heart dose (MHD), V5, and V30 and early changes in echocardiography-derived measures of cardiac function were assessed with generalized estimating equations. RESULTS: The median (quartile 1, quartile 3) estimates of MHD ranged from 1.2 Gy (1.0-1.9) in patients with breast cancer (n = 39), to 6.8 Gy (4.0-12.5) in patients with mediastinal lymphoma (n = 17), and 19.4 Gy (11.3-21.7) in patients with lung cancer (n = 13). There were no significant changes in 3D echocardiography measures in patients with breast cancer over time. However, in patients with lung cancer/lymphoma, there was a worsening in 3D left ventricular ejection fraction, GLS, and average 3D strain from pre-RT to RT completion (P < .05). This worsening in 3D GLS persisted at 5 to 9 months (P < .05). Across the entire cohort, MHD, V5, and V30 were not associated with changes in global 3D echocardiography-derived measures (P > .05). CONCLUSIONS: Early abnormalities in cardiac function as measured by 3D echocardiography can be detected following RT. Additional work is needed to define the determinants of changes in cardiac function with RT and long-term impact of early changes on clinical outcomes.