BackgroundThe high cardiotoxicity morbidity and mortality rates associated with the
antineoplastic therapy for breast cancer could be reduced with the early use
of cardioprotective drugs. However, the low sensitivity of left ventricular
ejection fraction limits its use in that preventive strategy. New
parameters, such as global longitudinal strain, are being used in the early
detection of contractile function changes.ObjectivesTo assess the incidence of cardiotoxicity in patients treated for breast
cancer, the independent factors associated with that event, and the ability
of strain to identify it early.MethodsProspective observational study of consecutive outpatients diagnosed with
breast cancer, with no previous antineoplastic treatment and no ventricular
dysfunction, who underwent anthracycline and/or trastuzumab therapy. The
patients were quarterly evaluated on a 6- to 12-month follow-up by an
observer blind to therapy. Cox regression was used to evaluate the
association of cardiotoxicity with clinical, therapeutic and
echocardiographic variables. A ROC curve was built to identify the strain
cutoff point on the third month that could predict the ejection fraction
reduction on the sixth month. For all tests, the statistical significance
level adopted was p ≤ 0.05.ResultsOf 49 women (mean age, 49.7 ± 12.2 years), cardiotoxicity was
identified in 5 (10%) on the third (n = 2) and sixth (n = 3) months of
follow-up. Strain was independently associated with the event (p = 0.004; HR
= 2.77; 95%CI: 1.39-5.54), with a cutoff point for absolute value of -16.6
(AUC = 0.95; 95%CI: 0.87-1.0) or a cutoff point for percentage reduction of
14% (AUC = 0.97; 95%CI: 0.9-1.0).ConclusionThe 14% reduction in strain (absolute value of -16.6) allowed the early
identification of patients who could develop anthracycline and/or
trastuzumab-induced cardiotoxicity.