The relationship between adjuvant chemotherapy and thiol-disulfide compounds

Aim: Thiols are the organic compounds of the antioxidant system. There is limited data in the literature concerning chemotherapy (CT) in cancer and thiol balance. In this study, we aimed to evaluate the possible changes of thiol/disulfide levels with the recurrent CT cycles and type of cancer. Materials and Methods: The 40 healthy individuals and 40 patients who had been newly diagnosed with early-stage breast, ovary and endometrium cancer receiving adjuvant CT. Blood samples were taken from all patients three times as basal and after the first and second CT sessions. Results: We compared preadjuvant treatment levels of thiol and disulfide parameters in the patients group with the control group. The median of native thiol and total thiol was found to be higher in the control group than in the study group (P < 0.001). In addition, disulfide/native thiol and disulfide/total thiol rates were found to be higher in the patient group (P = 0.001). When we look at the comparison before and after CT in the patient group, disulfide/native thiol and disulfide/total thiol rates, which represent increased oxidative stress (OS) levels were found to be higher after CT than before CT measurement (P < 0.016). Discussion: This is the first study, which has researched the relationship between cancer type and thiol compounds and changes of thiol compounds during CT therapy, by using the method designed by Erel and Neselioglu. In this study, we found that pre-CT thiol disulfide balance in cancer patients shifted toward disulfide direction and OS levels may increase after repetitive CT sessions.