Abstract:
Background: Prostate cancer (PCa) is an important and universal health problem of the man, particularly in developed countries. Prostate specific antigen (PSA) levels in blood do not provide the high reliability and precision required for an accurate screening for PCa. There is a need in a simple, rapid, direct, preferably non-invasive, and highly accurate biomarker and procedure for the screening for PCa.
Objective: To report the results from a Russian population-based randomized study of a screening using the zinc (Zn) level in expressed prostatic fluid (EPF) to detect PCa.
Methods: A total of 578 Russian ambulatory males aged over 50 years had their Zn levels in EPF determined. Men with their EPF Zn levels < 100 mg/L were subjected to further clinical examination including digital rectal examination (DRE) and transrectal prostate biopsy.
Results: The Zn levels in EPF (mean ± standard deviation, SD) in all the men (n=578) was 618±377 mg/L and, for those of them with PCa (n=3), the mean Zn level was 15±20 mg/L (
p≤0.001). The Zn level in EPF increased with age up to 70 years but over 71 years old this metal’s concentration began to decrease. In persons aged 51-60, 61-70, 71-80, and above 81 years, the mean ± SD values of the Zn levels in EPF were 602±329 (n=135), 655±395 (n=324), 539±354 (n=103), and 455±432 (n=16) mg/L, respectively. Among all the screened men, 33 (5.7%) had a Zn concentration in EPF < 100 mg/L. Of the patients who underwent prostate biopsy (n=11), 3 had PCa (positive predictive value, 27.3%).
Conclusion: The usefulness of Zn levels in EPF as a reliable biomarker for the screening for PCa needs to be confirmed in other randomized trials.
