Oxidative stress status in metastatic breast cancer patients receiving palliative chemotherapy and its impact on survival rates

Abstract

Antineoplastic agents are known to induce the production of free radicals leading to cell damage. These adverse effects may fuel the acquisition of new mutations and the development of treatment resistances. We selected 30 metastatic breast cancer patients receiving palliative chemotherapy, and paired blood samples, before and after chemotherapy, were extracted. We analysed DNA, lipid and protein oxidative damage markers and determined the extent of antioxidant and repair defences activation at the systemic level. We found that the DNA repair activity of the KU86 enzyme was significantly lower after chemotherapy and the antioxidant capacity of the plasma was significantly higher after treatment. Cox regression analysis revealed a significant effect of KU86 activity on the survival rates of those patients who received anthracyclines as part of their treatment. The high clinical heterogeneity of metastatic breast cancer patients warrants further studies to clarify the role of DNA repair and systemic antioxidant capacities during chemotherapy.

Keywords::

• DNA oxidation
• plasma antioxidants
• DNA repair
• disease-free survival
• metastasis

Acknowledgements

We thank the patients who made this study possible. We also thank Dr. Monica Fernandez Navarro, Capilla de la Torre and Manuela Exposito for their contribution to patient selection and statistical work and the oncologists and nurses at the Department of Oncology of the Complejo Hospitalario de Jaen for their collaboration.

This paper was first published online on Early Online on 18 November 2011.