Introduction: Recently, the prognosis of patients with HER2‑positive breast cancer (BC) has improved significantly owing to the use of combined treatment modalities. However, systemic treatment is as-sociated with increased risk of cardiotoxicity.
Objectives: We aimed to assess subclinical cardiac alterations during the final stage of adjuvant com-bined therapy, that is, trastuzumab therapy (TT), as potential predictors of late cardiac complications in patients with HER2‑positive BC.
Patients and methods: We enrolled 251 patients with HER2‑positive BC treated with a radical local therapy, adjuvant chemotherapy (anthracyclines or anthracyclines + taxanes), and immunotherapy (trastuzumab). Patients underwent 6 echocardiographic examinations: at baseline, during TT, and after TT, with assessment of left ventricular ejection fraction (LVEF), degree of valvular regurgitation, and cardiac chamber diameters.
Results: Valvular fibrosis (28.4% of patients) was associated with older age, hypertension at baseline, and a higher degree of regurgitation during TT. Reduced LVEF, greater regurgitation, and larger cardiac chamber diameters were noted during TT. The patients who received higher anthracycline doses showed a greater degree of aortic insufficiency and a larger right ventricular diameter. Reduced LVEF during TT was associated with radiotherapy or chemotherapy and the degree of valvular regurgitation. Significantly larger diameters were observed in older patients and in those with comorbidities at baseline, high body mass index, and regurgitation.
Conclusions: Asymptomatic subclinical cardiac alterations during TT may predict late cardiac complica-tions; however, longer follow‑up is necessary to confirm this hypothesis. Patients with HER2‑positive BC should be closely monitored for possible cardiac alterations during and after therapy to ensure optimal care and guide therapeutic decision‑making.