Cardiac tolerability of concurrent administration of trastuzumab and anthracycline-based regimen as adjuvant chemotherapy for breast cancer.

Background: Retrospective analysis suggests that anthracycline-containing regimens may be superior to non-anthracycline-containing regimens in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, both trastuzumab and anthracycline have cardiotoxicity, and it remains unclear how to use trastuzumab in combination with an anthracycline to curtail their cardiotoxicity.

Patients And Methods: From 2010 to 2013, we administered weekly (q1w) paclitaxel (wP) followed by 75 mg/m(2) epirubicin, fluorouracil, and cyclophosphamide (FEC) every third week (q3w) and concurrent q1w trastuzumab (H) to 41 patients with HER2-positive breast cancer (H+ group), and wP followed by FEC100 without trastuzumab to 57 patients who were HER2-negative (H- group). We routinely assessed the left ventricular ejection fraction (LVEF) by echocardiography, at the time of initiation, after wP, and after FEC, and compared them between these 2 groups.

Results: LVEF decreased from 63.2 to 60.9% (p = 0.030) in the H+ group and from 63.9 to 61.9% (p = 0.009) in the H- group. These 2 groups showed no significant difference in the reduction rate of LVEF over the period of chemotherapy (0.968 vs. 0.978: NS, p = 0.6457). There was no severe cardiotoxicity or congestive heart failure in either group.

Conclusion: Concurrent administration of epirubicin (q3w, 75 mg/m(2)) and trastuzumab showed no less cardiac tolerability in an adjuvant setting.