Serum oxidative stress markers and genotoxic profile induced by chemotherapy in patients with breast cancer : a pilot study

The aim of this study was to evaluate the oxidative parameters of erythrocytes and genotoxicity in leukocytes of patients with breastcancer.Oxidativeparametersweredetectedbyspectrophotometryandgenotoxicdamagebysinglecellgelelectrophoresis. Twenty-eight women with breast cancer were monitored before chemotherapy and after the second and fourth cycles of therapy withcyclophosphamideanddoxorubicin.Afterthefourthcycle,increases( < 0.05)inthereactivesubstancestothiobarbituric acid levels, nitrite content, and superoxide dismutase activity and high rates of DNA damage in leukocytes were observed when compared with healthy women group and baseline levels. Similarly, after the second cycle, the same parameters were increased ( < 0.05)whencomparedwithbaselinelevels.Increaseincatalaseactivitywasdetectedonlyafterthefourthcycleandreduced glutathione levels and glutathione peroxidase activity were decreased in all cycles when compared with healthy women, as well as after the second and fourth chemotherapy cycles compared to baseline ( < 0.05). Patients with breast cancer presented an indicativeofoxidativestressbefore,during,andafterchemotherapy,aswellasincreasedgenotoxicdamageinallstagesoftreatment, demonstratingtheclinicalapplicabilityofthisinvestigation