Aim: The aim of the present study was to assess metastasis-free survival of 134 patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with chemotherapy, radiotherapy and trastuzumab in an adjuvant setting, according to sub-clinical cardiac side-effects (parameters not tested previously) evaluated before, during and after trastuzumab therapy, as well as selected clinicopathological parameters.
Results: In our series, left ventricular ejection fraction decreased significantly from 68.1% before trastuzumab treatment to 66.7% after therapy (p<0.001). Further analysis revealed that this decrease was significant only in patients who received radiotherapy and developed valve insufficiency during or after (but not before) trastuzumab therapy (p<0.001). Cox multivariate analysis revealed that both pN2a tumor stage and valve regurgitation during/after trastuzumab therapy (vs. lack of valve insufficiency or insufficiency before trastuzumab therapy) were significant independent factors for a negative prognosis.
Conclusion: Valve insufficiency diagnosed during or after trastuzumab application might be cancer-unrelated indicator of decreased sensitivity to trasuzumab.
Keywords: Breast cancer; HER2-positive; left ventricular ejection fraction; trastuzumab; valvular regurgitation.
Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.