(ChemotherapyAdvisor) – Cardiac magnetic resonance (CMR) imaging identified a high prevalence of cardiomyopathy among adult survivors of childhood cancer previously undiagnosed with cardiac disease, according to results of a study published in the Journal of Clinical Oncology online July 16 that compared two-dimensional (2D) echocardiography, currently recommended by the Children’s Oncology Group Guidelines to screen for treatment-related cardiomyopathy, to CMR, the reference standard for left ventricular (LV) function.

“More than 80% of children diagnosed with a malignancy will become 5-year survivors of their cancer, the majority of whom will survive into adulthood,” noted Gregory T. Armstrong, MD, MSCE, of St. Jude Children’s Research Hospital, Memphis, TN, and colleagues. Among the estimated 328,600 survivors, many may have received therapy “documented to have an adverse impact on cardiac function in the immediate treatment period and to increase the risk for reduced LV function later on in adolescence and young adulthood,” they wrote.

The investigators evaluated LV structure and function by 2D and 3D echocardiography and CMR imaging in 114 adult survivors of childhood cancer exposed to anthracycline chemotherapy and/or chest-directed radiation therapy. Current median age was 39 years (range, 22 to 53). By CMR, 16 patients (14%) had an ejection fraction (EF) <50%. The 108 patients previously undiagnosed with cardiotoxicity had a high prevalence of EF (32%) and cardiac mass (48%) more than two standard deviations below the mean of normative CMR data. The mean EF of this population was overestimated by 5%.

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When compared with CMR for detection of EF <50%, 2D echocardiography had a sensitivity of 25% and a false-negative rate of 75%; this was 53% and 47%, respectively, for 3D echocardiography. Twelve survivors with an EF <50% by CMR were misclassified as ≥50% (range, 50% to 68%) by 2D echocardiography. Using a higher 2D echocardiography cutoff (EF <60%) to detect an EF <50% by the reference standard CMR improved detection of cardiomyopathy to a sensitivity of 75%.

“In conclusion, we showed that 2D echocardiography demonstrates limited performance for detection of reduced EF among survivors of childhood cancer treated with chemotherapy or RT. CMR identifies that even previously undiagnosed survivors who received low-dose anthracycline exposure have significant rates of subclinical dysfunction. These findings should inform clinical use of echocardiography for screening by suggesting a lower threshold for additional cardiology referral in this population exposed to cardiotoxic therapy.” They recommended that survivors with an EF 50% to 59% by 2D echocardiography be considered for comprehensive cardiac assessment, which may include CMR.

Link to abstract: