Early cardiotoxicity after Adjuvant Concomitant Treatment with Radiotherapy and Trastuzumab in Patients with Breast Cancer

Abstract

Purpose: The purpose of the study was to find out whether there is a difference in the early parameters of cardiotoxicity (left ventricular ejection fraction (LVEF) and N-terminal pro-B-type natriuretic peptide (NT-proBNP)) between the two groups of patients: the patients treated for left breast cancer (BC) (left BC group) and those treated for the right breast cancer BC (right BC group), after the treatment had been completed.

Methods: The study included 175 consecutive patients with HER2-positive early BC, treated concurrently with Trastuzumab (T) and radiotherapy (RT), between June 2005 and December 2010. Echocardiography with LVEF (LVEF₁) and NT-proBNP measurements was performed in all patients after the treatment had been completed. The difference (Δ) between LVEF, measured before adjuvant RT (LVEF₀) and LVEF₁ was analysed (Δ LVEF = LVEF₀ -LVEF₁) and compared between the two groups.

Results: There were 84 patients in the left and 91 in the right BC group. Median observation time was 57 (37- 71) months. Mean Δ LVEF (%) was -1.786% in the left and -2.607% in the right BC group (p = 0.562, CI: -2.004 to 3.648). Median NT-proBNP was 111.0 ng/ l in the left and 90.0 ng/ l in the right BC group (p =0.545). Echocardiography showed that the patients in the left BC group did not have significantly worse systolic and diastolic left ventricular function in comparison with the patients in the right BC group, but they had higher incidence of pericardial effusion (9 (11%) vs 1 (1%)) (p = 0.007).

Conclusions: We did not find any significant differences in the early parameters of cardiotoxicity (LVEF, NT-proBNP) between the two groups we observed. Those patients who were irradiated on the left breast/chest wall had higher incidence of pericardial effusion.