Relationship between prostate size and percent free prostate-specific antigen in patients with operable prostate cancer.
BACKGROUND
The free-to-total prostate-specific antigen ratio is the best marker for optimizing prostate cancer detection. The main problem with studies of percent free PSA is the variability of reported cutoff values.


OBJECTIVE
To evaluate the influence of prostate size on the ratio of free to total PSA.


METHODS
The study group included 58 patients (mean age 66.4 years) with clinically localized prostate cancer treated surgically at our institution. Total PSA and free PSA levels were measured by a solid phase enzyme immunoassay test (Hoffman-La Roche, Basel, Switzerland). The percent free PSA was compared with prostate size as determined from the surgical specimen.


RESULTS
A direct relation was noted between prostate size and the percent free PSA value (r = 0.49, P = 0.0001). Mean percentage free PSA was 9% +/- 0.004 in men with normal-sized gland while in men with large prostate (> 60 g) the average percent free PSA was 15.9 +/- 0.09 (P = 0.001).


CONCLUSIONS
In patients with prostate cancer the percent free PSA level is influenced by the gland size. The larger the prostate the higher the proportion of the free PSA. Such information may have influence on the recommendation for prostate biopsy in screening programs for early detection of prostate cancer.
Nativ
O
O
Department of Urology, Bnai Zion Medical Center, Haifa, Israel. dr_nativ@netvision.net.il
Sabo
E
E
Wald
M
M
Halachmi
S
S
Moskovitz
B
B
D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011184:Postoperative Period; D011336:Probability; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011468:Prostatectomy / Q000379:methods; D011470:Prostatic Hyperplasia / Q000175:diagnosis / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen