Serum copper and zinc content in non-small cell lung cancer: abnormalities and clinical correlates

This study was carried out in order to assess the potential prognostic significance of serum copper (SCL) and zinc levels (SZL) and the copper/zinc ratio in 145 consecutive patients, seen for a new lung cancer during the last 2 yrs. SCL and SZL, along with 26 other clinical parameters (anthropometric, clinical and laboratory variables) were prospectively recorded in all the patients. Mean SCL and SZL were, respectively, 140.4 micrograms.dL-1 (134.7-146.1, 95% confidence interval (CI), and 71.4 micrograms.dL-1 (66.8-75.9, 95% CI). Patients, 28%, showed abnormally elevated SCLs, and 57% of patients had abnormally low SZLs. The mean Cu/Zn ratio was 2.28 (2.10-2.46, 95% CI). Univariate analyses of survival showed that patients with either an SCL > 138 micrograms.dL-1 or an ZSL < 66 micrograms.dL-1 survived significantly shorter times (p = 0.03, log rank test). Elevated Cu/Zn ratios (> 2.075) were associated with a median survival of 25.39 weeks, as compared to the 40.85 weeks of subjects with lower ratios (p = 0.01). A multivariate analysis of survival (Cox's proportional hazards regression analysis) selected, in decreasing order of significance, the following variables: 1) stage of disease; 2) Eastern Cooperative Oncology Group performance status; 3) sex; 4) Cu/Zn ratio; 5) lymphocyte count; 6) histology; and 7) tissue polypeptide antigen levels. It is concluded that SCL, SZL and the Cu/Zn ratio are simple and inexpensive determinations, and do have some prognostic significance in lung cancer.