NT-pro-BNP and CA 125 as potential markers of mortality during long-term immunetherapy with trastuzumab in HER-2-positive metastatic breast cancer

804 Background: Immunetherapy with trastuzumab (TR, herceptin, Roche), a selective HER-2(ErbB2)-antibody, is approved in women with metastatic breast cancer (MBC). During TR monotherapy cardiotoxicity is noted in 7% of patients (pts). Both, nt-pro-BNP (brain natriuretic peptide) and CA 125 are reported to be associated with the degree of clinical heart failure. The aim of this study is to determine pro-nt-BNP and CA 125 during longterm immunetherapy regarding mortality. Methods: In 28 female patients with metastatic HER-2-positive breast cancer blood samples before and 30min after intravenous TR infusion were drawn. Depending on the nt-pro-BNP-levels 155pg/ml (group B, n=12, age 62±9 years, n.s.) two groups have been defined. Median time to initial TR-dosis was 93±86 weeks (A) vs. 117±38 weeks (B, n.s.), respectively. Results: The echocardiographic determined ejection fraction (EF%) before immunetherapy initiation was 68±3% (A) vs. 72±4% (B), lowe...