Subclinical Myocardial Damage after Anthracycline Chemotherapy in Patients with Breast Cancer

Purpose: Data on the incidence, timing, and prediction of myocardial damage after anthracycline-based chemotherapy (AC) in patients with breast cancer are limited. We assessed myocardial damage in these patients following AC, using the high-sensitivity troponin I (TnI) assay. Methods: We prospectively assessed TnI levels in women with breast cancer (n=51) at baseline (before the first AC), 1 week, and 1, 2, 3, 6, 9,12, and 15 months after low-to-moderate doses of AC. Subclinical myocardial damage was diagnosed when TnI levels exceeded the 99th percentile (26 pg/mL). Echocardiograms were obtained at baseline and 3, 6, 9, 12, and 15 months post-AC. Results: Subclinical myocardial damage was detected in 43% of the patients: in 0%, 3.9%, 7.8%, 33%, 29%, 6.7%, 2.3%, and 2.3% of patients at 1 week and 1, 2, 3, 6, 9, 12, and 15 months after starting AC, respectively. From baseline to 1 week post-AC, median absolute change in TnI levels was 1.6 (interquartile range: 0.1–3.5) pg/mL. Absolute change in TnI levels ≥1.6 pg/mL at 1 week was associated with a higher peak TnI level during follow-up (p=0.042). Conclusions: Approximately half of the patients had subclinical myocardial damage, frequently observed at 3 or 6 months post-AC. TnI level changes at 1 week after the first AC may predict subsequent myocardial damage.