Antioxidant Modulation of Hematological Toxicity during Chemotherapy for Breast Cancer

Abstract

Side effects of anticancer drugs seriously limit the achievement of the maximum therapeutic effect of the most cytostatic. One of the pathophysiological bases of side effects is the ability of cytotoxic agents to intensify the freeradical processes and the consequent lipid peroxidation (LPO) in the cell membranes of various organs. When the antitumor treatment is conducted, the antioxidant enzyme deficiency increases, there is the depletion of nonenzymatic and enzymatic mechanisms of oxidation protection units, resulting in a reduction of organism resistance and damage to vital organs and systems. In this connection it is important to study the possibility of correction of violations occurring in cancer patients with drugs with antioxidant action type.Classic example of breast cancer individualization treatment is by determining of reproductive hormones and epidermal growth factor [8]. Prognostic value of ER and PR determination for endocrine therapy is confirmed by meta-analysis of 55 randomized trials with 37000 breast cancer patients. It is proved that ER expression in breast tumor indicates potential responsiveness to drug treatment, this is aimed to remove estrogens source and its effect recovering. PR is the first step in cell reaction to progestines and it determines cell responsiveness to some drugs, but mainly because it synthesis in breast cancer cells is prompt by estrogens. Presence of PR confirms ER functional activity. Breast cancer patients who has both or at least one of steroid hormones receptors have more favorable prognosis than those has no receptors. Thus 75% of patients with both positive receptors responses effectively to endocrine therapy and 50% with only ER positive receptor. However there was response to endocrine therapy in 10% of patient with both negative receptors [9].A high level of estrogen receptors is associated, in front of all, with an increase in overall and not relapse-free survival, and is a predictor of the effectiveness of hormone therapy. In recent years Ki-67 proliferation index has been used to predict the effectiveness of treatment [10]. The panel of estrogen progestin receptor markers, Her2/neu and Ki-67, is today standard both at the stage of primary diagnosis and in morphological studies in the course of treatment. Taking into account these four markers, the main immunomorphologic subtypes of breast cancer are listed above. In the case of neoadjuvant treatment or treatment of metastatic cancer (if there is a possibility of re-biopsy in the dynamics), Ki-67 has recently been used as a marker for the effectiveness of treatment. Repeated biopsy is performed after 3 weeks of treatment. Decrease of marker level is the first morphological