Evaluation of the Total Oxidant Status to the Antioxidant Capacity Ratio as a Valuable Biomarker in Breast Cancer Patients.

Background: The oxidative balance is a state of equilibrium between oxidants and antioxidants disrupted in various disorders, including BC. This study aimed to assess this equilibrium in breast cancer (BC) patients by looking at the oxidant-to-antioxidant ratio.

Methods: This case-control study comprised 40 women patients with breast cancer and 30 age-matched healthy individuals. The oxidation-reduction colorimetric technique was used to determine serum levels of total oxidant status (TOS) and total antioxidant capacity (TAC). The oxidant-to-antioxidant balance was estimated using the TOS- to- TAC ratio (TOS/TAC).

Results: The mean TOS in healthy individuals was 8.40±2.06 µmol/L, while in BC patients it was 13.31±2.16 µmol/L (P< 0.001). The mean serum level of TAC was 1.43±0.21 mmol/L in healthy individuals and 1.19±0.15 mmol/L in BC patients (P< 0.001). The mean serum TOS/TAC was 6.01±0.32 in the healthy individuals and 11.42±0.41 in the BC patients (P< 0.0001). There were direct correlations between TAC and estrogen receptor (r=0.339, P=0.038). The TOS/TAC level has a sensitivity of 100% and specificity of 83.33%, distinguishing patients with BC from healthy controls (P< 0.001). A significant trend of increasing risk with rising TOS/TAC levels was also seen [OR=3.62, (95 % CI 1.79, 7.35)].

Conclusions: In breast cancer, the serum TOS to TAC ratio can better diagnose oxidative equilibrium than either component alone.