Use of percentage of free prostate-specific antigen to identify men at high risk of prostate cancer when psa levels are 2.51 to 4 ng/mL and digital rectal examination is not suspicious for prostate cancer: an alternative model

• Published in: Urology (Ridgewood, N.J.) N.J.), 1999-08, Vol.54 (2), p.220-224
• Main Authors: Catalona, William J, Partin, Alan W, Finlay, Judith A, Chan, Daniel W, Rittenhouse, Harry G, Wolfert, Robert L, Woodrum, David L
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Humans; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Palpation; Prostate-Specific Antigen - blood; Prostatic Neoplasms - blood; Prostatic Neoplasms - diagnosis; Rectum; Retrospective Studies; Risk Factors; Tumors of the urinary system; Urinary tract. Prostate gland
• ISSN: 0090-4295; 1527-9995
• DOI: 10.1016/S0090-4295(99)00185-5

Objectives. Currently, many clinicians do not recommend prostate biopsy for men with digital rectal examination (DRE) results that are not suspicious for cancer and prostate-specific antigen (PSA) values between 2.51 and 4 ng/mL. We propose a new model for the detection of prostate cancer using the percentage of free PSA (%FPSA) in the limited range of PSA values between 2.51 and 4 ng/mL that maximizes clinical specificity (ie, minimizes false-positive results). This model identifies higher risk patients in this relatively low-risk population. Methods. Three hundred sixty-eight archived serum samples from men evaluated and treated at two academic institutions were reviewed. All men had a histologic diagnosis, findings not suspicious for cancer on DRE, and PSA levels between 2.51 and 4 ng/mL. Samples were tested in Hybritech’s Tandem-R PSA and Tandem-R free PSA (FPSA) assays in the same laboratory at each institution. Results. Various models for cancer detection using %FPSA when PSA is 2.51 to 4 ng/mL and DRE is not suspicious for cancer are proposed. These models recommend biopsy for only 10% to 36% of the men in this population and would identify as many as 30% to 54% of the detectable cancers. There is evidence that the cancers that would be detected are the most aggressive cancers in this population. Conclusions. Our models identified men with a higher risk of prostate cancer in a relatively low-risk population that currently does not routinely undergo biopsy. This may allow for a more cost-effective way to increase cancer detection when PSA values are between 2.51 and 4 ng/mL and DRE is not suspicious for cancer. This model has the potential to detect a greater number of clinically important and potentially curable cancers than would be detected with current practice.