Aim: To investigate whether the measurement of serum zinc may improve the detection of prostate cancer (PCa) in men who had total prostate-specific antigen (PSA) levels higher than 4.1 ng/mL.
Methods: A mass screening for PCa of 3940 men over 50 years old was undertaken using total serum PSA. Of the 190 men (4.8%) with elevated PSA, 143 (3.6%) underwent a transrectal ultrasonography (TRUS)-guided biopsy of the prostate, and 42 men (1% of total and 29.3% of men undergoing biopsy) were found to have cancer. The areas under the receiver operating characteristic curves (ROC-AUC) were used to compare the diagnostic power of cancer detection by means of serum zinc, and free PSA/total PSA ratio (f/t).
Results: The men with levels of serum zinc that ranged from 40 ng/mL-60 ng/mL, had an age-adjusted odds ratios(OR) of 5.0. A cutoff value of 100 microg/mL for serum zinc concentration provided a sensitivity of 90.5% and a specificity of 32.7% in elevated PSA range, and a sensitivity of 93.3% and specificity of 27.1% in gray zone, respectively. In the gray zone ranges of 4.1 ng/mL-10.0 ng/mL, the ROC-AUC for zinc was 73.0% higher than 62.7% of f/t PSA ratio and 56.7% of total PSA.
Conclusion: PCa displays a lower serum zinc concentration. The measurement of zinc levels improves PCa detection in the gray zone compared with the f/t PSA ratio and total PSA.