RATIO OF FREE TO TOTAL PROSTATE-SPECIFIC ANTIGEN IN PATIENTS WITH PROSTATIC INTRAEPITHELIAL NEOPLASIA

Objective: There are many reports about the effects of prostatic intra epithelial neoplasia (PIN) on serum prostate-specific antigen (PSA) le vel. The aim of this study was to determine the relationship between P IN and serum free PSA/total PSA (fPSA/tPSA) ratios. Methods: We evalua ted 46 patients with PIN, 15 patients with benign prostatic hyperplasi a (BPH), and 16 patients with localized prostatic carcinoma (CaP) for the amount of fPSA and tPSA with the chemiluminescent enzyme assay. Re sults: fPSA values from BPH to high-grade PIN (PIN2 and PIN3) was incr eased, and then a decrease was observed from high-grade PIN to CaP. fP SA was significantly different between BPH and low-grade PIN and high- grade PIN. There was no significant difference observed between BPH an d CaP, tPSA values increased from BPH to CaP, tPSA was significantly d ifferent between BPH and high-grade PIN and CaP, fPSA/tPSA ratios decr eased from BPH to CaP, This ratio was significantly different between CaP and BPH and low-grade PIN. There was no significant difference bet ween CaP and high-grade PIN. Conclusions: Our results confirm that fPS A/tPSA ratio is better at discriminating between patients with CaP and those with BPH, but not between patients with CaP and those with high -grade PIN. Due to similarities between CaP and high-grade PIN, we thi nk that decreased fPSA/tPSA ratio obtained at the time of intial diagn osis of PIN without concurrent carcinoma could be used as predictive f actors to distinguish patients in whom carcinoma will be found on subs equent biopsies from those with PIN not associated with cancer on repe at biopsy.