Comment on "Chemotherapy-Induced Left Ventricular Dysfunction in Patients with Breast Cancer".

To the Editor,

I want to congratulate Yoon et al. [1], who investigated the incidence and predictors of chemotherapy-induced left ventricular dysfunction (LVD) in patients with breast cancer. They reported that low body mass index, advanced cancer stage, and the use of trastuzumab were independent predictors of chemotherapy-induced LVD in patients with breast cancer. In addition to these findings, new serum markers were identified for prediction of trastuzumab-related cardiac dysfunction (TRCD) [2]. Zardavas et al. [3] explored the prognostic value of cardiac markers (troponins I and T, N-terminal prohormone of brain natriuretic peptide) to identify patients at increased risk for TRCD among those with early-stage human epidermal growth factor receptor 2-positive breast cancer receiving trastuzumab (HERA substudy). The authors reported that elevated troponin I or T before trastuzumab therapy is associated with increased risk for TRCD. Associated with this, a recent study by Beer et al. [4] investigated new biomarkers associated with doxorubicin- and trastuzumab-induced cancer therapeutics-related cardiac dysfunction (CTRCD) using high-throughput proteomic profiling; they found that high baseline immunoglobulin E levels are associated with a lower risk of CTRCD, highlighting the role of the immune system as a potential mediator of CTRCD. Thus, evaluation of the aforementioned serum markers may improve the identification of patients at increased risk for TRCD.

We thank Dr. Kadri Altundag for the important comments on our study. We also wanted to investigate the role of natriuretic peptide and cardiac troponins in the prediction of chemotherapy-induced left ventricular dysfunction (LVD). This issue could not be evaluated because the present study was retrospective and cardiac biomarkers were not measured in many of the study subjects. We agree that the measurement of several cardiac biomarkers would be useful in the early identification of chemotherapy-induced LVD [12]. However, in the early-stage prediction of chemotherapy-induced LVD, the optimal timing for the measurement of biomarker remains unclear. Therefore, further large-scale randomized studies will be needed to investigate this issue.