The value of the ratio of free-to-total prostate specific antigen for staging purposes in previously untreated prostate cancer.
OBJECTIVE
We analyzed the use of the ratio of free-to-total prostate specific antigen (PSA), also termed percentage of free PSA, for predicting tumor stage, volume and grade in patients with clinically localized prostate cancer.


METHODS
A total of 515 consecutive patients underwent further prostate evaluation due to elevated PSA (greater than 4.0 ng./ml.) or abnormal digital rectal examination. Prostate cancer was diagnosed in 307 patients (59.6%), including 170 (55.4%) who underwent radical retropubic prostatectomy. Data on pathological stage, Gleason grade, and total and Gleason grade 4 cancer volume were available in all patients. In the remaining 208 men (40.4%) benign prostate hyperplasia was diagnosed. Total and free PSA was measured in preoperative serum.


RESULTS
Total PSA was significantly higher (p <0.0001) in the 71 men with stage pT3 tumors than in the 91 with pT2 disease. Eight patients had stage pT4 tumors. Cancer volume correlated well with advancing pathological stage (p <0.0001) and total PSA (p <0.0001). The free-to-total PSA ratio was not significantly different (p = 0.93) in stages pT2 and pT3 tumors, and it did not correlate with total (p = 0.71) or pure Gleason grade 4 (p = 0.94) cancer volume. However, the ratio of free-to-total PSA tended to decrease (p = 0.07) in tumors of increasing Gleason grade.


CONCLUSIONS
The ratio of free-to-total PSA does not help in the preoperative prediction of final tumor stage and volume. However, disease grading may alter the free-to-total PSA ratio.
Noldus
J
J
Department of Urology, University Hospital Eppendorf, Hamburg, Germany.
Graefen
M
M
Huland
E
E
Busch
C
C
Hammerer
P
P
Huland
H
H
D014408:Biomarkers, Tumor / Q000097:blood; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood* / Q000601:surgery
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen