PERCENTAGE OF FREE PROSTATE-SPECIFIC ANTIGEN IN SERA PREDICTS AGGRESSIVENESS OF PROSTATE-CANCER A DECADE BEFORE DIAGNOSIS

Objectives. To evaluate serial measurements of free and total prostate -specific antigen (PSA) as a predictor of prostate cancer aggressivene ss. Methods. Twenty men diagnosed with adenocarcinoma of the prostate in the pre-PSA era had serum PSA measurements made on multiple stored frozen sera samples available for up to 18 years prior to diagnosis. S ubjects were categorized as having aggressive cancer (n = 12) based on the presence of clinical Stage T3, or nodal or bone metastases (N+, M +), or pathologic positive-margin disease, or a Gleason score of 7 or greater; nonaggressive cancer (n = 8) was identified by the absence of these criteria. Results. There was no statistically significant diffe rence in free PSA levels among men with aggressive and nonaggressive p rostate cancers from 0 to 15 years before diagnosis. Total PSA levels were significantly different between the groups by 5 years before diag nosis (P = 0.04). At a time when total PSA levels were not different b etween groups (10 years before diagnosis), there was a statistically s ignificant difference in the percentage of free PSA between aggressive and nonaggressive cancers (P = 0.008). Among 14 men who had sera avai lable for analysis at 10 years before diagnosis, all 8 men with aggres sive cancers had a percent free PSA of 0.14 or less; this compares wit h only 2 of 6 men (33%) with nonaggressive cancer. Conclusions. These data suggest that the percentage of free PSA in sera is predictive of tumor behavior at a time when total PSA levels provide no information on tumor aggressiveness. Evaluation of the percentage of free serum PS A may be helpful in making the decision between expectant management a nd treatment for those men who are diagnosed with early prostate cance rs by PSA testing. (C) 1997, Elsevier Science Inc.