Lipopolysaccharide-Binding Protein Is an Early Biomarker of Cardiac Function After Radiation Therapy for Breast Cancer

Abstract

To evaluate the prognostic potential of lipopolysaccharide-binding protein (LBP) levels after breast cancer radiation therapy (RT) for incipient cardiac dysfunction. In this single-centered study, we prospectively enrolled female patients treated for left breast cancer. Healthy age- and sex-matched participants were recruited as controls. LBP levels, cardiac troponin T, N-terminal propeptide of the brain natriuretic peptide, fatty acid binding protein, and C-reactive protein were assessed at three timepoints-before RT, after the last RT fraction, and 1month after the last fraction. Echocardiographic evaluation was done 3 to 3.75years after RT. We recruited 51 patients and 78 controls. Baseline LBP concentrations in the study group were significantly higher than in controls at baseline (P<.001), at 24hours, and at 1month after RT (P=.003 and P<.001, respectively). Other biomarkers (cardiac troponin T, N-terminal propeptide of the brain natriuretic peptide, fatty acid binding protein, and C-reactive protein) did not differ in any of the timepoints. Posttreatment LBP concentrations were significantly and positively correlated with heart- and lung-associated dose-volume histogram variables. Posttreatment and follow-up LBP levels correlated positively with the E/E' echocardiographic index reflective of the diastolic function. After adjustment for left anterior descending artery mean dose, left ventricle mean dose, mean heart dose, and type of surgery, LBP remained significantly correlated with E/E' when measured 24hours after RT (beta=0.41, P=.032) and 1month after RT (beta=0.43, P=.028). Serum LBP concentrations correlate with diastolic function evaluated 3years after the completion of RT, making LBP a potentially useful prognostic parameter.