Use of various combinations of free, complexed and total prostate-specific antigen levels as predictors of the pathologic stage of prostate cancer

BACKGROUND: The efficacy of various combinations of total, free and complexed prostate-specific antigen (PSA) levels were assessed to predict the pathologic stage of prostate cancer. METHODS: Total PSA (tPSA), free PSA (fPSA) and complexed PSA (cPSA) levels were measured preoperatively in 52 patients with clinical localized prostate cancer who had undergone radical prostatectomy. Pathologic stages were classified as: organ-confined (n = 27); capsular penetration (n = 14); seminal vesicle involvement (n = 8); involvement of the surgical margins (n = 10); and lymph node involvement (n = 3). RESULTS: The fPSA/tPSA and fPSA/cPSA ratios significantly differed between patients with organ-confined disease and non-organ-confined disease (P = 0.035, P = 0.033, respectively) and between those with favorable versus unfavorable pathology (P = 0.001, P = 0.014, respectively), but tPSA, cPSA, fPSA and the cPSA/tPSA ratio did not. Using a fPSA/tPSA cutoff level of 11%, the prediction of organ-confined disease would increase from 52 to 67% and the rate of predicting favorable pathology would increase from 42 to 62%. A fPSA/cPSA cutoff level of 12% would increase the rate of predicting organ-confined disease to 79% and the rate of predicting favorable pathology would increase to 69%. The positive predictive value of the fPSA/cPSA ratio was higher than that of the fPSA/tPSA ratio, although the receiver operating characteristic curve of the fPSA/cPSA ratio was not different from that of the fPSA/tPSA ratio. CONCLUSION: Although there was no predictive difference found between fPSA/tPSA and fPSA/cPSA ratio, both ratios may help predict the pathologic stage of prostate cancer.