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

Objectives. Prostate-specific antigen (PSA) levels, transrectal ultras ound, and systematic sextant biopsies have each shown limited ability to predict prostate cancer volume. In combination, these studies may a llow more accurate estimation of volume and prognosis. Methods. One hu ndred twenty-four patients were evaluated prior to radical prostatecto my. Interactive stepwise multiple regression and separate logistic reg ression analysis were performed for prediction of prostate cancer volu me 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%, res pectively. Conclusions. The formula for prediction of cancer volume co rrelates well with actual cancer volume in 92 patients but is not adeq uate to predict volume for an individual patient. The formulas for pre diction of Volume range show promising predictive ability and may be u seful if the extent of disease is unclear.