Prediction of preclinical myocardial damage utilizing cardiac biomarkers and ultrasound myocardial tissue characterization by integrated backscatter in patients with breast cancer treated with postoperative adjuvant radiotherapy.

Abstract

169 Background: To evaluate whether cardiac biomarkers, ultrasonic integrated backscatter (IBS) can predict early myocardial damage in breast cancer patients treated with postoperative adjuvant radiotherapy. Methods: Forty-eight left-sided breast cancer patients treated with modified radical mastectomy and non-anthracycline containing chemotherapy regimen were examined. Baseline blood samples were drawn for cardiac markers analysis, including Troponin T (TnT), C-reactive protein (CRP), and brain natriuretic peptide (BNP). Calibrated myocardial IBS (CMIBS, assessed by comparison of the anterior wall (AW), inferior wall (IW), anteroseptum (AS) and posterior wall (PW) with pericardial IBS intensity), cyclic variation of IBS (CVIBS) and conventional echocardiography parameters (LVIDd: the left ventricular internal diameter at end-diastole; IVSTd: the intraventricular septal thickness at end-diastole; PWTd: the posterior wall thickness at end-diastole; LVDs: the left ventricular end-systolic dimension; EF: the left ventricular ejection fraction; FS: the left ventricular fractional shortening. The peak velocity of early (E) and late ventricular filling (A) were also determined for calculating the ratio E/A) were investigated before the initiation of radiotherapy (group A), during (group B, 3 weeks after the initiation, the cumulative dose was about 30Gy) and after radiotherapy (group C, 5 weeks, the cumulative dose was about 50Gy). At each time point, blood was drawn to measure TnT, CRP, and BNP. Results: TnT, CRP, and BNP did not change over time. CMIBS of AW and AS were significantly increased after radiotherapy both during (group B, p<0.05) and at the end of treatment (group C, p<0.01) and meanwhile CVIBS and E/A were decreased significantly throughout the treatment period (group B, p<0.05 for both; group C, p<0.01 for both) compared with the beginning (group A). Conclusions: Myocardial IBS offers a promising approach for early clinical detection and characterization of evolution of cardiomyopathy induced by radiotherapy in breast cancer patients.