BACKGROUND

Trastuzumab following anthracycline causes cardiotoxicity in up to 28% of patients. Although the cardiotoxicity is often irreversible once cardiac dysfunction is detected, the early predictor has not been established yet.

METHODS

We prospectively observed breast cancer patients treated with anthracycline or trastuzumab at Tonan Hospital. All patients underwent echocardiography and blood sampling at baseline, and every three months during chemotherapy. Cardiotoxicity was defined as a decline in left ventricular ejection fraction >10% points.

RESULTS

Of 40 patients, 34 patients (85%) were treated with anthracycline (epirubicin), 18 (45%) with trastuzumab, and 12 (30%) with both agents. Cardiotoxicity was observed in four patients (10%), who were all treated with both agents. The absolute levels of high-sensitive troponin T (hs-TnT) were increased in all four patients with cardiotoxicity, and all the highest points were observed before or at the time of detection of cardiotoxicity. The highest level of hs-TnT was not significantly different in patients with and without cardiotoxicity. "Hs-TnT increment from baseline to the highest value" and "hs-TnT integration value above baseline" were significantly greater in patients with cardiotoxicity (0.039 vs. 0.007 ng/mL, P = 0.046, 0.113 vs. 0.022 ng months/mL, P = 0.013, respectively). The integration value had 100% sensitivity and specificity with a cutoff level at 0.070 ng months/mL.

CONCLUSIONS

Hs-TnT assay may be able to predict anthracycline- and trastuzumab-induced cardiotoxicity in breast cancer patients, and the hs-TnT increment or hs-TnT integration value above baseline was more reliable than the absolute value.