Cardiac monitoring and toxicity with adjuvant trastuzumab in breast cancer: Data from clinical practice

Abstract

17551 Background: Adjuvant trastuzumab, recommended for HER2-positive early stage breast cancer, is associated with asymptomatic drop in left ventricular ejection fraction (LVEF) in 10–15% of patients and symptomatic congestive heart failure in 2–4%. There are limited data on cardiac toxicity with trastuzumab in clinical practice and there is no standard cardiac follow-up during adjuvant treatment. Phase III trials (NSABP B31/NCCTG N9831/ HERA) recommended echocardiograms at baseline, after anthracyclines and every 3 to 6 months afterwards. Methods: Retrospective evaluation of all patients with HER2-positive breast cancer treated in a private clinic with adjuvant trastuzumab since its approval in 2005. Timing and frequency of echocardiograms and cardiac adverse events were reviewed. Results: Forty-seven patients received adjuvant trastuzumab until December 2007. Thirty-three (70%) finished 1-year treatment and 14 are still on treatment (median 6 months, range 3–11). Median age: 51 years (range 31–82). No patient had uncontrolled hypertension or heart failure at baseline. Adjuvant chemotherapy was an anthracycline followed by taxanes in 41 patients (87.2%), anthracycline/ cyclophosphamide in 4 (8.5%) and docetaxel/ carboplatin in 2 (4.3%). Twenty-one patients (44.7%) have not received appropriate cardiac monitoring (considering published phase III trials). Seven patients (14.9%) had to discontinue trastuzumab (6 cases of asymptomatic LVEF drop and 1 symptomatic arrhythmia). Three patients resumed trastuzumab after 1-month interval. Four patients (8.5%) required permanent discontinuation of trastuzumab (3/7/11/11 months): 3 for a significant drop in LVEF (≤ 50%) and 1 due to arrhythmia). All these patients recovered from cardiac dysfunction and LVEF returned to baseline/ normal levels after treatment interruption (1 still on medication). Conclusions: Despite the absence of standard guidelines, our results show inadequate cardiac monitoring during adjuvant trastuzumab in a private clinic. Cardiotoxicity was observed as often as in clinical trials. Severity was mild and reversible in all patients. Continued and appropriate cardiac follow-up of these women is of critical importance. No significant financial relationships to disclose.