Antioxidant status in advanced cervical cancer patients undergoing neoadjuvant chemoradiation

Abstract

Cervical cancer is the most common cancer in Indian women. The aim of this study is to assess the alterations in the circulating lipid peroxide, antioxidant components and activities of defence enzymes in advanced cervical cancer patients, and to monitor the variations in their levels before and after neoadjuvant chemoradiation. Sixty patients with advanced cancer of the cervix (FIGO IIIa–IVb) are included in the study, along with 60 healthy controls. Blood samples are collected before the start of therapy (S1), two weeks after the second course of chemotherapy (S2) and two weeks after completion of tele/brachyradiation (S3). Single blood samples are taken from controls. Lipid peroxides, conjugated dienes, reduced glutathione (GSH), catalase (CAT) and glutathione-S-transferase (GST) are estimated using standard methods. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) are assayed using commercially available kits. The pretreatment levels of plasma lipid peroxide were significantly elevated in cancer patients, while significantly lowered levels of GSH, GPx, GST, SOD and CAT were observed when compared to controls. After chemotherapy, the levels of lipid peroxidation showed a significant decline (P<0.05), which became highly significant after chemoradiation (P<0.01). Levels of GSH, GPx, SOD, GST and CAT showed a mild increase after chemotherapy. After chemoradiation, levels reverted to normal or near normal (P<0.01). Low levels of antioxidants in the circulation of patients with cervical cancer may be due to their increased utilisation to scavenge lipid peroxidation as well as their sequestration by tumour cells. The observed increase in antioxidant concentration after therapy might be due to the death of tumour cells or the arrest of tumour growth by chemotherapeutic agents. The normalisation of these parameters may provide information about the efficacy of neoadjuvant chemoradiation. A larger patient cohort with a longer follow-up period for therapeutic response studies may yield more significant data.