Effects of Chemotherapy and Hormone Therapy on Biomarkers of Cardiac Injury and Oxidative Stress in Women with Breast Cancer

Abstract

The increase in deaths from cardiovascular disease in women submitted to antineoplastic treatments for breast cancer is a fact observed in many work and is most often associated with cardiotoxic effects of chemotherapy. It is believed that the cardiotoxicity of chemotherapeutic agents is associated with increased oxidative stress in the body, although not well understood. The detection of this damage underlies the aims of this present study to assess the effects of treatments against breast cancer on biomarkers of cardiac injury and oxidative stress. Thirty women divided according to the therapeutic protocol in women treated only with hormone therapy with tamoxifen (Tam group, n = 10), women treated only with chemotherapy (chemo group, n = 10), and women treated with chemotherapy and then with hormone therapy with tamoxifen (Chemo+Tam group, n = 10) were monitored for one year. Blood samples was collected before initiation of treatment, six, and twelve months after for analysis of cardiac troponin I (cTnI), advanced oxidation protein products (AOPP) and plasma activity of the antioxidant enzyme glutathione peroxidase (GPx). At the end of research we observed that women in the Chemo group showed increased levels of cTnI and AOPP and lower plasma activity of GPx when compared to women groups Tam and Chemo + Tam. These data reinforce the involvement hypothesis of oxidative stress in cardiovascular diseases in a chronic period after end of chemotherapy and highlighted a cardioprotective effect of hormone therapy with tamoxifen.