PREDICTION OF PROSTATE-CANCER VOLUME USING PROSTATE-SPECIFIC ANTIGEN LEVELS, TRANSRECTAL ULTRASOUND, AND SYSTEMATIC SEXTANT BIOPSIES

Objectives. Prostate-specific antigen (PSA) levels, transrectal ultrasound, and systematic sextant biopsies have each shown limited ability to predict prostate cancer volume. In combination, these studies may allow more accurate estimation of volume and prognosis. Methods. One hundred twenty-four patients were evaluated prior to radical prostatectomy. Interactive stepwise multiple regression and separate logistic regression analysis were performed for prediction of prostate cancer volume and volume range. Results. The cancer volumes calculated correlated with the volumes in the radical prostatectomy specimens with R(2) of 0.76. Cancers were predicted to be in the volume range associated with poor prognosis (more than 12 cc) or clinically insignificant cancer (less than 1.0 cc) with bias corrected error rates of 5.3% and 10%, respectively. Conclusions. The formula for prediction of cancer volume correlates well with actual cancer volume in 92 patients but is not adequate to predict volume for an individual patient. The formulas for prediction of Volume range show promising predictive ability and may be useful if the extent of disease is unclear.