Serum Copper Level and the Copper-to-Zinc Ratio Could Be Useful in the Prediction of Lung Cancer and Its Prognosis: A Case-Control Study in Northeast China

Background The association between lung cancer and trace element levels, such as serum copper (Cu) and zinc (Zn) levels and the Cu:Zn ratio, vary among different demographic groups; however, it is unknown whether variations in serum Cu and Zn levels and Cu:Zn ratios are related to the prediction and prognosis of lung cancer. We aimed to clarify this relationship in the Han Chinese population of Northeast China.Methods We recruited 146 patients with lung cancer and 146 age- and resident area-matched cancer-free controls.Results Increased serum Cu and Zn levels and the Cu:Zn ratio were positively associated with lung cancer (OR: 72.243, 95% CI 24.159–216.030; OR: 3.513, 95% CI, 1.476–8.358, and; OR: 58.582, 95% CI, 20.023–171.395, respectively). The critical serum Cu level for the prediction of lung cancer was 1.37 mg/L (sensitivity, 77.4%; specificity, 84.9%), while the critical Cu:Zn ratio was 1.45 (sensitivity, 69.9; specificity, 88.4%). Patients with stage IV non-small-cell lung cancer (NSCLC) had higher serum Cu levels and a higher Cu:Zn ratio than patients with stage I, II, or III NSCLC.Conclusions The serum Cu level and the Cu:Zn ratio are effective predictive indicators of lung cancer and may help evaluate the prognosis of patients with NSCLC.