A. Reissigl et al., USEFULNESS OF THE RATIO FREE TOTAL PROSTATE-SPECIFIC ANTIGEN IN ADDITION TO TOTAL PSA LEVELS IN PROSTATE-CANCER SCREENING/, Urology, 48(6A), 1996, pp. 62-66
Objectives, Two different studies were performed, The aim of the first
study was to define whether the measurement of the ratio between free
and total prostate-specific antigen (fit PSA) in serum may enhance th
e ability of PSA-based screening for early detection of prostate cance
r in men with Elevated serum PSA levels. A second study was undertaken
to investigate the value of fit PSA ratio in serum to improve the spe
cificity of prostate cancer screening in men with serum SA levels betw
een 2.5 and 10,0 ng/mL. Methods, In a retrospective study of 266 men w
ith elevated PSA levels and proven biopsy results, fit PSA levels were
measured using deep frozen serum samples. In a second study we enroll
ed 158 men with elevated PSA levels according to age reference ranges
apparent from our current PSA screening study with additional measurem
ent of the fit PSA rat io. All study volunteers with a free fit PSA ra
tio cutoff point of less than or equal to 22% underwent digital rectal
examination, transrectal ultrasonography, and biopsy of the prostate.
Free and total PSA levels were measured with the Delfia PSA dual labe
l fit PSA kit (Wallac Oy Turku, Finland), Results. 106 of 158 men with
elevated total PSA values between 2.5 and 10.0 ng/mL (group 1) have b
een further evaluated and 37 prostate cancers were detected. Mean perc
entage of free PSA was 10% in men with cancer and 22% in men with beni
gn prostatic hyperplasia. Using a fit PSA ratio of less than or equal
to 22% as a biopsy criterion 30% of the negative biopsies could be eli
minated while still detecting 98% carcinomas. Conclusions. Measurement
of fit PSA reduces the number of unnecessary biopsies in PSA screenin
g without missing many cancers.