Myocardial injury detected by T1 and T2 mapping on CMR predicts subsequent cancer therapy-related cardiac dysfunction in patients with breast cancer treated by epirubicin-based chemotherapy or left-sided RT.

OBJECTIVES: Cancer therapy-related cardiac dysfunction (CTRCD) is a relevant clinical problem and needs early prediction. This study aimed to analyze myocardial injury using serial laboratory and cardiac magnetic resonance imaging (CMR) parameters after epirubicin-based chemotherapy compared with left-sided radiotherapy and to study their value for early prediction of CTRCD. METHODS: Sixty-six consecutive women (53 ± 13 years) including n = 39 with epirubicin-based chemotherapy and n = 27 with left-sided radiotherapy were prospectively studied by 3 T CMR including left ventricular (LV) mass and volumes for ejection fraction (LVEF), as well as feature-tracking with global longitudinal strain (GLS) and T1/T2 mapping. CMR was performed at baseline, at therapy completion (follow-up 1, FU1), and after 13 ± 2 months (FU2). CTRCD was defined as LVEF decline of at least 10% to < 55% or a > 15% GLS change at FU2. RESULTS: T1 and T2 increased at FU1 after epirubicin-based chemotherapy, but not after left-sided radiotherapy. CTRCD occurred in 20% of patients after epirubicin-based chemotherapy and in 4% after left-sided radiotherapy. T1 at FU1 was the best single parameter to predict CTRCD with an area under the curve (AUC) of 0.712 (CI 0.587-0.816, p = 0.005) with excellent sensitivity (100%, 66-100%), but low specificity (44%, 31-58%). Combined use of increased T1 and LVEF ≤ 60% at FU1 improved AUC to 0.810 (0.695-0.896) resulting in good sensitivity (78%, 44-95%) and specificity (84%, 72-92%). CONCLUSION: Only epirubicin-based chemotherapy, but not left-sided radiotherapy, resulted in increased T1/T2 myocardial relaxation times as a marker of myocardial injury. Combined use of CMR parameters may allow an early prediction of subsequent CTCRD. KEY POINTS: • Myocardial T1 and T2 relaxation times increased at FU1 after epirubicin-based chemotherapy, but not after left-sided radiotherapy. • Cancer therapy-related cardiac dysfunction (CTRCD) occurred in 20% of patients after epirubicin-based chemotherapy and in 4% after left-sided radiotherapy. • Combined use of increased T1 and reduced LVEF had an AUC of 0.810 (0.695-0.896) to predict CTRCD with good sensitivity (78%, 44-95%) and specificity (84%, 72-92%).