Trastuzumab is a highly efficient drug in HER2-positive breast cancer that increases patient survival. Due to cardiotoxicity is the most important side effect of trastuzumab treatment, cardiac monitoring should be a priority, especially in the presence of comorbidities. Left ventricle ejection fraction (LVEF) determination remains the most used technique to diagnose cardiotoxicity in clinical practice. The purpose of this study is to analyse the usefulness of NT-ProBNP as a biomarker of cardiotoxicity in breast cancer patients treated with trastuzumab.
The study included 66 patients who received trastuzumab. We collected the LVEF and NT-proBNP values measured during the course of treatment, and cardiovascular risk factors including diabetes, hypertension, smoking, hypercholesterolemia and BMI. Cardiotoxicity was diagnosed during the follow-up program considering a decrease of the LVEF from baseline or clinical manifestation of congestive heart failure. According to the literature, NT-proBNP cut-off points were considered to stablish normal or abnormal values in terms of patent age.
174 paired LVEF/NT-proBNP values were found. 27.3% of patients suffered cardiotoxicity during trastuzumab treatment and most of cases were diagnosed based on cardiac symptomatology (66.7 %). Logistic regression analysis of NT-proBNP and the cardiovascular risk factors showed a significant association of diabetes mellitus (OR 5.9, 95% CI 1.2 - 28.5, p = 0.028) and NT-proBNP (OR 22.0, 95% CI 5.7 - 85.4, p = 0.000) with the development of cardiotoxicity during trastuzumab treatment, whereas the other variables were not statistically significant.
Diabetes and NT-proBNP values seem to be associated with an increased risk of cardiotoxicity in breast cancer patients during trastuzumab treatment. In diabetics, glycaemic control and a more intense cardiac monitoring could provide objective benefits during the treatment. Moreover, NT-proBNP determination could become an accessible way to evaluate cardiac risk in this context.
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All authors have declared no conflicts of interest.