FREE, COMPLEXED, AND TOTAL SERUM PROSTATE-SPECIFIC ANTIGEN CONCENTRATIONS AND THEIR PROPORTIONS IN PREDICTING STAGE, GRADE, AND DEOXYRIBONUCLEIC-ACID PLOIDY IN PATIENTS WITH ADENOCARCINOMA OF THE PROSTATE

Objectives. Nearly half of men with clinically localized prostate canc er are understaged. We evaluated whether knowledge of preoperative fre e prostate-specific antigen (f-PSA), complexed (c-PSA), and total (t-P SA) concentrations or the ratios thereof (f-PSA/t-PSA, c-PSA/t-PSA, an d f-PSA/c-PSA) could improve upon the staging of prostate cancer when compared with standard PSA testing (t-PSA). In addition, we examined t heir associations with tumor grade and deoxyribonucleic acid (DNA) plo idy. Methods. Two hundred ninety patients with prostate cancer, 178 (6 1%) of whom were treated with radical prostatectomy, formed the study group. Results. Although there were significant differences in the f-P SA concentrations with respect to clinical stage, considerable overlap in PSA levels among the clinical substages was observed. Statisticall y significant differences but weak correlations were observed between the individual f-PSA, c-PSA, and t-PSA concentrations with regard to p athologic stage (organ-confined versus extraprostatic) and grade, No s ignificant relationship, however, was observed with the three ratios. Higher PSA values were not always associated with a pathologic stage o f pT3 or greater, and lower levels did not ensure that a tumor was org an-confined. Only a slight association was observed between c-PSA and t-PSA levels and DNA ploidy. No significant relationship was observed between the f-PSA levels as well as the three ratios with regard to DN A ploidy. A statistically significant improvement in predicting pathol ogic stage was observed when combining knowledge of preoperative t-PSA concentration with the c-PSA/t-PSA ratio. However, the area under the receiver operator characteristic curves was only slightly increased; as such this combination was of limited clinical utility.Conclusions. Statistically significant but weak correlations were observed between the molecular forms of PSA and stage, grade, and DNA ploidy. The signi ficant overlap in f-PSA and c-PSA values among all stages, grades, and ploidy values precluded any useful predictive information for the ind ividual patient. As such, preoperative knowledge of f-PSA and c-PSA va lues and the three ratios provided no additional diagnostic informatio n over standard PSA (t-PSA) values alone.