Clinical significance of serum total oxidant/antioxidant status in patients with operable and advanced gastric cancer

Purpose: Oxidative stress was significantly associated with the development of malignancies. The purpose of this study was to evaluate the significance of serum total oxidant/antioxidant status in operable advanced gastric cancer patients. Materials and methods: A total of 284 patients who underwent curative resection for primary stage III gastric cancer were enrolled. Total oxidant status, total antioxidant status, and oxidative stress index (OSI) were evaluated within 24 hours before surgery, and compared with 120 healthy donors. The correlation between the OSI and survival outcome was analyzed by the Kaplan-Meier method with log-rank test and Cox's regression methods, respectively. Results: Mean OSI of gastric cancer patients was higher than healthy controls (1.41 +/- 0.96 vs 0.78 +/- 0.42, P<0.001). All patients were stratified into two groups using the optimal cutoff value (1.42) of OSI using a sensitivity of 94.1% and a specificity of 64.0% as optimal conditions from receiver operating curve analysis. Patients with an OSI >= 1.42 had poorer mean overall survival (45.6 vs 29.8 months, P=0.022) and mean recurrence-free survival (43.3 vs 28.1 months, P=0.011) than patients with an OSI <1.42 in univariate analysis, and OSI was also confirmed as an independent predictor for survival for gastric cancer in multivariate analysis (hazard ratio, 0.541; 95% CI: 0.127-1.102; P=0.01). Conclusion: Preoperative OSI can be considered as an independent prognostic factor for operable and advanced gastric cancer.