P5-20-02: N-Terminal Pro-Brain B-Type Natriuretic Peptide (nt-pro-BNP) before and during Treatment with Trastuzumab Allows Early Detection of Cardiotoxicity in Breast Cancer Patients.

Abstract

Abstract Background: The treatment with Trastuzumab (T) is associated with a certain degree of cardiotoxicity. This study sought to evaluate the level of nt-pro-BNP as a possible marker of cardiotoxicity so accurate as the value of left ventricular ejection fraction (LVEF) Patients and methods: Forty patients with breast cancer treated with T were prospectively measured LVFE with echocardiography and nt-pro-BNP level before and every 3 months during T treatment. Median age: 50years(27;70). Received T as adjuvant treatment: 82.5% of the patients and 17.5% for metastatic disease.Patients with previous chemotherapy: 13(32.5%)neoadjuvant, 23(57.5%)adjuvant and 7(17.5%) for metastastic disease. Patients with previous treatment with anthracyclines: 12(30%)neoadjuvant, 21(52.5%)adjuvant and 2(5%)for metastatic disease(one patient had received anthracyclines too during adjuvant treatment).None received anthracyclines and T concomitant. Chi-square analyzed the correlation of high pathological level of nt-pro-BNP (values over the normal ***range, adjusted by the patient age) and a significative decrease of LVEF (more than 10% when LVEF >50% or more than 5% when LVEF< 50%) Results: A decrease in LVEF was observed in 6 patients(15%) and pathological high levels of nt-pro-BNP in 7(17.5%).Two patients(5%) presented cardiac insufficiency with clinical symptoms, in both nt-pro-BNP was higher than 600pg/ml and LVEF lower than 40%. In the other patients the decreases of LVEF(never were<40%) or high levels of nt-proBNP(never were>600pg/ml)were not related to any clinical symptoms. Chi-square analysis showed a correlation between pathological high levels of nt-pro-BNP and significative decrease of LVEF (p=0.001), The estimated risk of a false negative nt-pro-BNP result (nt-pro-BNP normal value and significative LVEF decrease) was 2.735% (95 % confidence interval: 0.878 to 8.522 %) and the estimated risk of a false positive nt-pro-BNP result (nt-pro-BNP pathological value and no significative LVEF decrease) was 0.132%(95% confidence interval: 0.39 to 0.448%) Conclusion:The level of nt-pro-BNP is a possible marker of cardiotoxicity so accurate as the value of LVEF in patients with breast cancer treated with T. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-20-02.