The free-to-total prostate specific antigen ratio improves the specificity of prostate specific antigen in screening for prostate cancer in the general population.
OBJECTIVE
The ratio between free and total prostate specific antigen (PSA) in serum improves the specificity of total serum PSA for the detection of prostate carcinoma in select populations. The value of the free-to-total PSA ratio for a PSA of 4.0 to 10.0 ng./ml. was analyzed in a screening population.


METHODS
From 4,800 participants 55 to 76 years old 977 biopsies were obtained because of an abnormal digital rectal examination, suspicious transrectal ultrasonography and total serum PSA 4.0 ng./ml. or more. Of 191 patients with prostate carcinoma detected 101 had a serum PSA of 4.0 to 10.0 ng./ml. and 54 of them underwent radical prostatectomy. A free-to-total PSA ratio of 0.20, age specific PSA reference ranges and a PSA density of 0.12 ng./ml./cc were evaluated for the ability to increase the specificity of total serum PSA in predicting positive prostate biopsy results.


RESULTS
Receiver operating characteristics curves for the free-to-total PSA ratio showed a significant increase in specificity compared to PSA. Retrospective application of age specific PSA reference ranges, the free-to-total PSA ratio and the PSA density decreased the number of biopsies significantly by up to 40% in our study, with a decrease in cancer detection rate of 12%. When used in combination with digital rectal examination, the pathological stage of undetected carcinomas appeared favorable.


CONCLUSIONS
The free-to-total PSA ratio may be used to decrease biopsies in patients with an intermediate PSA of 4.0 to 10.0 ng./ml.
Bangma
C H
CH
Department of Urology, Academic Hospital Rotterdam, The Netherlands.
Rietbergen
J B
JB
Kranse
R
R
Blijenberg
B G
BG
Petterson
K
K
Schröder
F H
FH
D000368:Aged; D001706:Biopsy; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D010173:Palpation; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000517:prevention & control; D012372:ROC Curve; D012680:Sensitivity and Specificity
D017430:Prostate-Specific Antigen