Prostate-specific antigen density adjusted for the transition zone for staging clinically localized prostate cancer in Japanese patients with intermediate serum prostate-specific antigen levels.

The prostate-specific antigen (PSA) density of the transition zone (PSATZ) in 45 prostate cancer patients who received radical prostatectomy with a PSA value of 4.1-10 ng/ml was determined to see whether PSATZ was useful in the prediction of extracapsular invasion of prostate cancer. The value of PSATZ for the detection of extracapsular invasion was compared with that of PSA and PSA density (PSAD). Thirty-one patients (68.9%) had pathologically organ confined cancer while 14 (31.1%) had extracapsular disease. Patients with organ confined tumor had significantly lower PSAD and PSATZ than those with non-organ confined tumor. PSATZ was superior to PSA when analyzed by receiver operating characteristics curves. In those patients with a cut-off value of 1.0 ng/ml per ml of transition zone volume, the PSATZ had a sensitivity of 43% and a specificity of 90% for prediction of extracapsular extension. The present study demonstrated that PSATZ was superior to PSA as a predictor of extracapsular invasion in intermediate PSA levels. Measurement of PSATZ may be of additional value to indicate the need for radical prostatectomy.