Evaluating the use of cardiac biomarkers for early detection of chemotherapy induced cardiotoxicity: A pilot study in a minority population

Abstract

e20546 Background: Doxorubicin and trastuzumab are associated with characteristic Type I and Type II cardiomyopathy. As breast cancer survival improves and concern about long-term cardiotoxicity grows, we will need appropriate markers to detect cardiotoxicity before measurable myocardial systolic dysfuntion. Recent data and several guidelines suggest that Troponin-I and B-type natriuretic peptide (BNP) may serve as cardiac biomarkers for early detection of cardiotoxicity. This study seeks to evaluate feasibility and utility of these markers in an outpatient oncology clinic setting. Methods: As a quality care initiative in a high risk minority patient population for cardiac disease, 55 consecutive patients who received doxorubicin and/or trastuzumab for the treatment of breast cancer had serum Troponin-I and BNP measured prior to each dose of doxorubicin, and every three months on trastuzumab. All patients also had normal baseline left ventricular ejection fraction (≥ 50%) measured by MUGA scan. IRB approval was obtained and medical records were reviewed independently by two authors. Results: Of the 55 patients, two did not have adequate data; 58% of patients received dose dense doxorubicin; 15% of patients received trastuzumab. Significantly more number of patients had troponin-I rise as compared to BNP. Total 7 (13%) patients had abnormal LVEF by MUGA scan following chemotherapy. Five (71%) of these patients had rise in Troponin-I/BNP. Negative predictive value of biomarkers was 91%, with sensitivity of 71% and specificity of 44%. Conclusions: Use of standard cardiac biomarkers to detect early cardiotoxicity is feasible with a high negative predictive value for Troponin I and BNP in the first 90 days following chemotherapy with doxorubicin and/or trastuzumab. Patients with normal markers may not need intense cardiac monitoring. [Table: see text] [Table: see text]