Objectives: To evaluate free prostate-specific antigen (PSA) and free to total PSA ratio as predictors of pathologic extent in Japanese patients with prostate cancer.
Methods: By TOSOH assay, pretreatment serum serologic markers of free PSA, total PSA, free to total PSA ratio, and PSA density (PSAD) were determined for 108 patients subsequent to radical prostatectomy for resectable prostate cancer. Serum values for these markers were compared with pathologic findings and tumor volume on the basis of pathologic assessment of whole mount section histology.
Results: Mean total PSA, free PSA, free to total PSA ratio, and PSAD significantly differed for pathologically confined (pT2 or lower) and advanced (pT3 or higher) cancers (P < 0.05). Total PSA, free PSA, and PSAD provided indication of seminal vesicle involvement, surgical margin status, nodal involvement, and total tumor volume (P < 0.05). Free PSA was more closely correlated with total tumor volume than the free to total PSA ratio; this ratio was not correlated with total tumor volume or specimen Gleason score. Free PSA and free to total PSA ratio were not found to be any more useful than total PSA and PSAD for predicting pT3 disease by receiver operating characteristic curve analysis. Multivariate logistic regression analysis and log likelihood ratio test results indicated little additional value of these parameters for predicting pT3 disease.
Conclusions: Contrary to previous reports, free PSA and the free to total PSA ratio are of little use subsequent to the diagnosis of prostate cancer.