Robust predictive markers are needed for early detection of trastuzumab-related cardiac dysfunction in breast cancer
To the Editor,
I want to congratulate Honda and colleagues for their article in which they evaluated left ventricular diastolic function during trastuzumab treatment in patients with HER2-positive breast cancer. The ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (e′, E/e′ ratio) as estimated by tissue Doppler imaging is a noninvasive surrogate for the left ventricular diastolic function. They reported that the degree of E/e′ elevation could have a role as a surrogate marker for predicting the left ventricular ejection fraction decline characteristic of trastuzumab-induced cardiotoxicity . It is worth mentioning other specific predictive markers for trastuzumab-related cardiac dysfunction (TRCD). Zardavas et al.  explored the prognostic value of cardiac markers [troponins I and T, N-terminal prohormone of brain natriuretic peptide (NT-proBNP)] to identify patients at increased risk for TRCD in patients with early-stage HER2–positive breast cancer receiving trastuzumab (HERA substudy). The authors reported that elevated troponin I or T before trastuzumab is associated with increased risk for TRCD. Furthermore, recent study by Beer et al.  investigated new biomarkers associated with doxorubicin- and trastuzumab-induced cancer therapeutics-related cardiac dysfunction (CTRCD) using high-throughput proteomic profiling and they found that high baseline immunoglobulin (Ig) E levels are associated with a lower risk of CTRCD, pointing out the immune system as a potential mediator of CTRCD. As a conclusion, evaluation of baseline Ig E level in addition to aforementioned cardiac markers may robustly identify patients at increased risk for TRCD.
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Conflict of interest
I have no conflict of interest to declare.