Serial changes of layer-specific myocardial function according to chemotherapy regimen in patients with breast cancer

Aims Chemotherapy-induced cardiotoxicity (CIC) is a significant complication, meanwhile myocardial damage might differ depending on chemotherapy agents and their timing. The aim of this study was to evaluate serial changes of layer-specific myocardial function in patients with breast cancer and their differences by the development time of CIC and chemotherapy agent. Methods and results A total of 105 consecutive patients with breast cancer (age: 52.3 ± 9.3 years) were enrolled. CIC occurred in 20 (19%) patients during 6-month. Endocardial and midmyocardial functions decreased in patients with or without CIC, with patients with CIC showing greater decreases during follow-up. Global longitudinal strain (GLS) change at 3-month was the most sensitive parameter to detect CIC. When new development of CIC was analyzed at 6-month, GLS was reduced earlier than the decrease of LVEF. In patients with CIC who were treated with anthracycline-based regimen for 3 months, endocardial GLS markedly decreased at 3 months and continued to decrease until 6 months. Patients with CIC who received trastuzumab therapy after anthracycline therapy showed further reduction in endocardial GLS at the 6-month follow-up, which was not shown in patients with CIC who received taxane therapy subsequently. Conclusion Myocardial function assessed by strain decreased in all patients with breast cancer receiving chemotherapy. The endocardial layer was the most vulnerable to chemotherapy-induced myocardial damage. Functional impairment was more profound in patients with CIC who received sequential anthracycline-trastuzumab chemotherapy. Thus, early evaluation of LV function might be necessary for all patients with breast cancer to detect CIC.