Usefulness of the ratio free/total prostate-specific antigen in addition to total PSA levels in prostate cancer screening

• Published in: Urology (Ridgewood, N.J.) N.J.), 1996-12, Vol.48 (6A Suppl), p.62-66
• Main Authors: Reissigl, A, Klocker, H, Pointner, J, Fink, K, Horninger, W, Ennemoser, O, Strasser, H, Colleselli, K, Höltl, L, Bartsch, G
• Format: Article
• Language: English
• Subjects: Aged; Humans; Male; Mass Screening; Middle Aged; Neoplasm Staging; Prospective Studies; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - pathology; Prostatic Neoplasms - prevention & control; Retrospective Studies; ROC Curve
• ISSN: 0090-4295
• DOI: 10.1016/S0090-4295(96)00612-7

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 (f/t PSA) in serum may enhance the ability of PSA-based screening for early detection of prostate cancer in men with elevated serum PSA levels. A second study was undertaken to investigate the value of f/t PSA ratio in serum to improve the specificity of prostate cancer screening in men with serum PSA levels between 2.5 and 10.0 ng/mL. In a retrospective study of 266 men with elevated PSA levels and proven biopsy results, f/t PSA levels were measured using deep frozen serum samples. In a second study we enrolled 158 men with elevated PSA levels according to age reference ranges apparent from our current PSA screening study with additional measurement of the f/t PSA ratio. All study volunteers with a free f/t PSA ratio cutoff point of < or = 22% underwent digital rectal examination, transrectal ultrasonography, and biopsy of the prostate. Free and total PSA levels were measured with the Delfia PSA dual label f/t PSA kit (Wallac Oy Turku, Finland). 106 of 158 men with elevated total PSA values between 2.5 and 10.0 ng/mL (group 1) have been further evaluated and 37 prostate cancers were detected. Mean percentage of free PSA was 10% in men with cancer and 22% in men with benign prostatic hyperplasia. Using a f/t PSA ratio of < or = 22% as a biopsy criterion 30% of the negative biopsies could be eliminated while still detecting 98% carcinomas. Measurement of f/t PSA reduces the number of unnecessary biopsies in PSA screening without missing many cancers.