Use of the Percentage of Free Prostate-Specific Antigen to Enhance Differentiation of Prostate Cancer From Benign Prostatic Disease

Abstract

MEASUREMENT of serum prostate-specific antigen (PSA) is widely used as an aid in the early detection of prostate cancer.¹ A limitation of PSA testing has been its relative lack of specificity within the 4.0- to 10.0-ng/mL range, a diagnostic gray zone in which prostate cancer is present in only 25% of patients. Most patients with prostate cancer and a PSA level less than 10.0 ng/mL have early-stage disease, whereas more than half of the patients with PSA levels above 10.0 ng/mL have advanced disease.¹ Thus, the detection of prostate cancer in its potentially curable stages requires the use of low PSA cutoffs for screening, which leads to many unnecessary biopsies.