RESUMO
AIM: In this study the effects of radiation therapy (RT) on serum oxidant/antioxidant status in breast cancer patients and the impact of age, BMI and clinical stage of the disease on the aforementioned variables were investigated. BACKGROUND: RT that is used for cancer treatment is dependent on the production of reactive oxygen species. MATERIALS AND METHODS: Eighty patients with breast cancer participated in this study and received RT at a dose of 50 Gy for 5 weeks. Blood samples were obtained in one day before and after the end of RT. Serum status of malondialdehyde (MDA), total antioxidant status (TAS), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were analyzed by spectrophotometry or ELISA and selenium (Se) level were analyzed by atomic absorption spectrometry. Paired t-test was used for comparing pre and post radiotherapy data. RESULTS: Before and after the radiotherapy, a significant increase in MDA level was observed, while a significant decrease in GPx activity, SOD, TAS and Se levels were found (p < 0.05). The level of the CAT enzyme had no significant changes (p = 0.568). The results showed some changes in the status of TAS, SOD and GPx which are associated with age, BMI and clinical stage of the disease. CONCLUSION: It seems that RT would have the potential to cause variations in the status of antioxidant/oxidant system. Although, some changes in variables were observed by sub-classification of the age, BMI and the disease stage, but it seems that these changes are not necessarily dependent to them.
RESUMO
BACKGROUND: There are studies that indicated dyshomeostasis of oxidant/antioxidant and trace elements in breast cancer patients, but the data regarding the status of these parameters in various stages of breast cancer are limited. The aim of this study was to highlight the status of these biochemical factors in various stages of breast cancer. METHODS: Fifty-eight breast cancers patients participated in this study and underwent staging work up for the assessment of disease stage. Serum total antioxidant capacity and lipid peroxidation were determined spectrophotometically. Glutathione peroxidase (GPX), catalase (CAT) and superoxide dismutase (SOD) levels were analyzed by ELISA method. The serum level of Cu, Mn and Zn was measured by atomic absorption spectrophotometer. Student t-test and one-way analysis of variance (ANOVA) were used to compare group means. RESULTS: All the patients included in the study classified as mild (stages I+II) and advanced stages (stages III+IV). Patients in advanced stage had lower serum antioxidant capacity and higher lipid peroxidation levels, but the differences were not statistically differet (P=0.690 and 0.666, respectively). Patients in advanced stage had higher, but not statistically different serum levels of CAT, GPX and SOD levels (p>0.05). Patients in both groups had to some extent similar serum Cu, Mn and Zn levels. CONCLUSION: There was no evidence of remarkable discrepancy in the status of analyzed factors in various stages of breast cancer. It seems that the severity of oxidative stress in different stages of breast cancer is similar to some extent.
