Baseline Troponin Level and Cardiac Toxicity in HER2-positive Early Breast Cancer Patients Receiving Trastuzumab

Background/Aim: There is controversy around the use of high-sensitive troponin T (hs-TnT) as an early biomarker of cardiac toxicity in patients with breast cancer on trastuzumab (T). Patients and Methods: Patients receiving adjuvant or neo-adjuvant T for early HER2-positive breast cancer were prospectively included. Trans -thoracic echocardiograms and matched hs-TnT before T and at 3, 6, and 9 months were performed on all patients. Congestive heart failure, cardiac death, a decline in left ventricular ejection fraction (LVEF) of more than 10% from baseline even if it is still within the normal range, or a drop in LVEF below 55% were all considered signs of cardiac toxicity. Results: In total, 24 patients (median age: 57; range=39-79 years) were enrolled. Anthracyclines were administered to all patients but three as part of neo/adjuvant treatment before T. Cardiovascular toxicity was observed in 3 out of 24 (12 .5%) patients: two non -symptomatic LVEF declines (8.3%) and one heart failure episode (4.2%). In the entire population, the mean baseline hs-TnT level was 10.1 +/- 8.8 pg/ml, and after 3, 6, and 12 months, no appreciable change was observed. Patients with cardiac toxicity had mean hs-TnT levels higher than those without (18.3 +/- 12.3 vs. 8.2 +/- 7.2 pg/ml; p=0.049). A definite trend was evident in the chi-square test (chi2=3.52; p=0.06). Conclusion: In anthracycline-exposed patients with early breast cancer, hs-TnT may be able to identify those at risk of developing cardiac toxicity during neo/adjuvant T treatment.