New Cardiac Abnormalities After Radiotherapy in Breast Cancer Patients Treated With Trastuzumab

• Published in: Clinical breast cancer Vol. 20; no. 3; pp. 246 - 252
• Main Authors: Nack, Elana, Koffer, Paul P., Blumberg, Charles S., Leonard, Kara Lynne, Huber, Kathryn E., Fenton, Mary Anne, Dizon, Don S., Wazer, David E., Hepel, Jaroslaw T.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.2020
• Subjects: Cardiotoxicity; Ejection fraction; Herceptin; Myocardial; Valvular; Herceptin; Cardiotoxicity; Myocardial; Ejection fraction; Valvular
• ISSN: 1526-8209; 1938-0666
• DOI: 10.1016/j.clbc.2019.12.006

To evaluate cardiac imaging abnormalities after modern radiotherapy and trastuzumab in breast cancer patients. All patients treated with trastuzumab and radiotherapy for breast cancer between 2006 and 2014 with available cardiac imaging (echocardiogram or multigated acquisition scan) were retrospectively analyzed. Cardiac abnormalities included myocardial abnormalities (atrial or ventricular dilation, hypertrophy, hypokinesis, and impaired relaxation), decreased ejection fraction > 10%, and valvular abnormalities (thickening or stenosis of the valve leaflets). Breast laterality (left vs. right) and heart radiation dose volume parameters were analyzed for association with cardiac imaging abnormalities. A total of 110 patients with 57 left- and 53 right-sided breast cancers were evaluated. Overall, 37 patients (33.6%) developed a new cardiac abnormality. Left-sided radiotherapy was associated with an increase in new cardiac abnormalities (relative risk [RR] = 2.51; 95% confidence interval [CI], 1.34-4.67; P = .002). Both myocardial and valvular abnormalities were associated with left-sided radiotherapy (myocardial: RR = 2.21; 95% CI, 1.06-4.60; P = .029; valvular: RR = 3.30; 95% CI, 0.98-10.9; P = .044). There was no significant difference in decreased ejection fraction between left- and right-sided radiotherapy (9.6% vs. 2.1%; P = .207). A mean heart dose > 2 Gy as well as volume of the heart receiving 20 Gy (V20), V30, and V40 correlated with cardiac abnormalities (mean heart dose > 2 Gy: RR = 2.00; P = .040). New cardiac abnormalities, including myocardial and valvular dysfunction, are common after trastuzumab and radiotherapy. The incidence of new abnormalities correlates with tumor laterality and cardiac radiation dose exposure. Long-term follow-up is needed to understand the clinical significance of these early imaging abnormalities. Incidental cardiac irradiation in women receiving breast or chest wall radiotherapy has been associated with various cardiovascular effects. We evaluated cardiac imaging abnormalities after modern radiotherapy and trastuzumab in breast cancer patients. New cardiac abnormalities, including myocardial and valvular dysfunction, are common, and the incidence of abnormalities correlates with tumor laterality and with cardiac radiation dose exposure.