Free to total prostate-specific antigen (PSA) ratio is superior to total-PSA in differentiating benign prostate hypertrophy from prostate cancer.
BACKGROUND
Serum prostate-specific antigen (PSA) exists in different molecular forms, and their respective concentration has been proposed as a useful tool to improve discrimination between benign prostatic hypertrophy (BPH) and prostate cancer (PC).


METHODS
The relevance of the free to total PSA ratio was prospectively studied in a selected urology clinic population of 420 patients. Total serum PSA ranged from 2.1 to 30 ng/ml; 154 had PC and 266 had BPH.


RESULTS
Receiver operating characteristic (ROC) curves were constructed for the total population (total-PSA range from 2.1 to 30 ng/ml) and for the diagnostic gray zone of 2.1-10 ng/ml. For the two groups, the free to total PSA ratio had a higher specificity than total-PSA for all sensitivity levels. Cut-off values were found to, vary with prostate weight.


CONCLUSIONS
Although free to total PSA ratio demonstrated better performances than total-PSA, its use in screening appears problematic, due to the low prevalence of prostate cancer.
Van Cangh
P J
PJ
Department of Urology, Saint Luc University Hospital, Brussels, Belgium.
De Nayer
P
P
Sauvage
P
P
Tombal
B
B
Elsen
M
M
Lorge
F
F
Opsomer
R
R
Wese
F X
FX
D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011470:Prostatic Hyperplasia / Q000175:diagnosis*; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity
D017430:Prostate-Specific Antigen