Effects of prostate manipulation on serum total and free prostate specific antigen, and free-to-total prostate specific antigen ratio

OBJECTIVE: To evaluate the effects of the different types of manipulation on prostate total specific antigen (tPSA), free prostate specific antigen (fPSA), and free-to-total prostate specific antigen (f/tPSA).

METHODS: A total of 160 males were enrolled from January 2006 to December 2009 in the Urology Department, Beijing Anzhen Hospital affiliated to the Capital Medical University, Beijing, China. Of these patients, 23 had digital rectal examination (DRE), 21 had urethral catheterization, 28 had rigid cystoscopy, 35 had prostate biopsy, 35 underwent transurethral resection of the prostate (TURP), and 18 underwent suprapubic prostatectomy. Blood samples were taken before, at 24 hours, and 4 weeks after the manipulation for PSA tests.

RESULTS: The DRE had no significant effect on PSA. Catheterization and cystoscopy exerted significant increases in tPSA at 24 hours. However, these small increases may not be clinically significant. The fPSA and f/tPSA were not significantly changed. There was a marked increase in tPSA and fPSA, associated with a decrease in f/tPSA at 24 hours after biopsy. No significant alterations were found in tPSA, fPSA, and f/tPSA at 4 weeks after catheterization, cystoscopy, and biopsy. The TURP and prostatectomy caused significant increases in tPSA and fPSA at 24 hours, associated with decreases in f/tPSA. The tPSA and fPSA values were below the baseline levels at 4 weeks after TURP and prostatectomy, however, f/tPSA remained constant.

CONCLUSION: The DRE, catheterization, and cystoscopy had no crucial effect on PSA. Prostatic biopsy, TURP and prostatectomy significantly affected the PSA levels, and their longitudinal courses should be considered while evaluating different forms of PSA levels.