Identification of Clinical and Laboratory Variables Associated with Cardiotoxicity Events Due to Doxorubicin in Breast Cancer Patients: A 1-Year Follow-Up Study

Cardiovascular adverse events in patients with breast cancer undergoing chemotherapy (CT) are frequent due to the high cardiotoxic potential of treatments, especially doxorubicin (DOXO). This study aimed to evaluate the association of plasma levels of various biomarkers with cardiotoxicity in women with breast cancer on DOXO-based chemotherapy. In this single center prospective cohort, 80 breast cancer patients who used DOXO as a first-line treatment for cancer were evaluated. Patients were assessed at three time points: before CT (T0), 1 week after (T1) and 12 months after DOXO treatment (T2). The predominant histological classification was ductal carcinoma, n = 72 (90.0%); the most frequent molecular classification was Human epidermal growth factor receptor-type 2 positive (HER2+), n = 34 (43.0%). In patients submitted to complementary treatment with trastuzumab (n = 23), there was no association with cardio-specific biomarkers. Evaluating the clinical variables and the laboratory parameters in T1 and T2 in relation to T0, the reduction any time of N-terminal-pro hormone B-type natriuretic peptide (NT-proBNP), triglycerides and hematocrit levels showed an association with higher cardiotoxicity risk. In addition, increased levels of troponin I (cTnI) and glycated hemoglobin (HbA₁c) showed an independent association with the occurrence of cardiotoxicity. These results suggest that the evaluation of these laboratory tests should be included routinely to identify breast cancer patients under DOXO treatment at cardiotoxicity risk.