Serum prostate-specific antigen values for the prediction of clinical stage and prognosis in patients with prostate cancer: an analysis of 749 cases.
BACKGROUND: The clinical significance of pretreatment serum prostate-specific antigen (PSA) values was studied to determine the ability to predict clinical stage and prognosis using a relatively large number of patients with prostate cancer. METHODS: Serum PSA values at diagnosis were analyzed from 749 patients with newly-diagnosed prostate cancer and registered in the Tokai Urological Cancer Registry. Correlations between the PSA value, the clinical stage and prognosis of the patients were evaluated. RESULTS: Serum PSA values at each stage of diagnosis showed positivity (> or = 3.6 ng/mL) in 23% (stage A1) to 91.2% (stage D2) of patients, and it was possible to obtain statistical differences between the stages, even between A1 and A2. Based on a cumulative study of PSA distribution, stages greater than A2 could be diagnosed using a cut-off of 7.2 ng/mL, with a 99.2% positive predictive value (PPV), and a 16.2% negative predictive value (NPV). At a PSA level of 10.8 ng/mL, stages greater than B2 could be predicted with a PPV of 95.3% but an NPV of 40.3%. Pretreatment PSA values were a significant prognostic indicator in stage D2 patients using 100 to 150 ng/mL as the cut-off values. These differences were primarily found in the poorly differentiated group, which showed a statistical difference using cut-off PSA values from 75 to 150 ng/mL. CONCLUSIONS: Serum PSA levels from a large number of patients can be used to predict the stage and prognosis of prostate cancer patients.