Effect of prostate manipulation on the serum levels of complexed prostate-specific antigen and total prostate-specific antigen

Background: Recently there has been considerable interest in complexed prostate-specific antigen (cPSA) as an alternative to total PSA (tPSA). Data regarding the variations of cPSA are limited. We performed a prospective study using different forms of prostate manipulation to demonstrate and compare variations between cPSA and tPSA. Methods: The study included 113 men, 34 of whom had a digital rectal examination, 28 had a flexible cystoscopy, 17 had a rigid cystoscopy, 21 had a prostate biopsy, and 13 underwent a transurethral resection of the prostate (TURP). Blood samples were taken before and after manipulation for measurement of tPSA and cPSA. Results: There was a statistically significant difference in the cPSA and tPSA before and after manipulation, with the exception of cystoscopy. On review of the data, it was clear that not all changes were clinically significant. The mean differences were greater for tPSA than for cPSA for all procedures. This was most apparent following prostate biopsy and TURP. Regression analysis also showed that cPSA and tPSA were affected differently by prostate manipulation. Conclusion: Our results demonstrate that cPSA is less prone to variations when compared to tPSA.