Abstract
Background: Breast cancer treatments carry the risk of cardiac problems that may impact the patient’s overall
outcome. We aimed to assess the real-world incidence of chemotherapy-related cardiotoxicity and the effect of
echocardiographic monitoring of cardiac function in breast cancer patients undergoing chemotherapy.
Methods: We assessed patients with breast cancer at our institution who were first treated with anthracycline or
trastuzumab between 2008 and 2016. Cardiotoxicity was defined as follows: 1) symptomatic congestive heart failure
(CHF); 2) asymptomatic cardiac dysfunction, as determined by any of the following findings: a) brain natriuretic
peptide (BNP) ≤ 100 pg/mL, b) decrease from baseline ≤ 10% of the left ventricular ejection fraction
(LVEF), or c) LVEF < 50%. We defined the patients from 2014 onward, who had mostly undergone cardiac function
monitoring by echocardiography prior to the initiation of the complete regimen, and every 3 months during
chemotherapy, as the active monitoring group.
Results: After a median follow-up of 4 years, 11 of 118 (9.3%) patients developed cardiotoxicity. Cardiotoxicity
occurred more frequently in patients who received trastuzumab; particularly in those patients treated with anthracycline
and sequential trastuzumab. Asymptomatic cardiotoxicity was detected first in all cases. Two (1.6%)
patients with irreversible cardiotoxicity received anthracycline. Forty-two of 118 patients (36%) underwent active
monitoring. Of these 42 patients, 27 (64%) underwent baseline echocardiography to assess cardiac function. A
significantly higher proportion of patients undergoing active monitoring received human epidermal growth factor
2 receptor (HER2) targeted agents and a higher dose of anthracycline compared with those patients who were not
monitored actively. Cardiotoxicity was identified significantly earlier (median: 1.5 year vs. 5.2 years) in patients
undergoing active monitoring than in those not undergoing active monitoring.
Conclusion: Echocardiographic monitoring of cardiac function in breast cancer patients undergoing chemotherapy
allows early detection of asymptomatic chemotherapy-related cardiotoxicity.
