LIMITATIONS OF SERUM PROSTATE-SPECIFIC ANTIGEN IN PREDICTING PERIPHERAL AND TRANSITION ZONE CANCER VOLUMES AS MEASURED BY CORRELATION-COEFFICIENTS

Purpose: We reexamined the relationship between preoperative serum pro state specific antigen (PSA) and prostate cancer volume in 290 patient s who underwent radical prostatectomy. Materials and Methods: Serum sa mples from 290 consecutive patients were remeasured with the automated monoclonal-monoclonal Tosoh AIA-600 assay, These values were correlat ed with individual cancer volume by measuring Pearson correlation coef ficients (r). Results: Cancer was noted in the transition zone in 31 p atients and in the peripheral zone in 259, Of the peripheral zone canc ers 133 (51.4%) were organ confined and 126 (48.6%) were nonorgan conf ined, including 12 (9.5%) with histologically confirmed lymph node met astasis (stage D1). The 259 peripheral zone cancers had a correlation coefficient with PSA (r = 0.499, p <0.0001), After distributing the 25 9 cases into cancer volume groups we found a large overlap in mean pre operative serum PSA, including 65 with 50% or greater Gleason grade 4 or 5 disease (r = 0.508), The correlation coefficients of cancer volum e with PSA in 133 organ confined cancers, 114 nonorgan confined cancer s without lymph node metastases and 12 nonorgan confined cancers with positive lymph nodes were 0.382, 0.438 and 0.363, respectively. The 31 transition zone cancers showed a correlation coefficient with PSA (r = 0.81). After excluding 2 cases with extreme PSA and cancer volume th e correlation coefficient decreased (r = 0.077).Conclusions: Even when remeasured with an automated monoclonal-monoclonal assay serum PSA al one is unable to predict preoperatively cancer volume or distinguish b etween organ and nonorgan confined cancer in peripheral and transition zone tumors of the prostate.