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 g/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.

Keywords: prostate cancer, prostate-specific antigen, zinc, gray zone

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