SIGNIFICANCE OF PREOPERATIVE PARAMETERS FOR PREDICTING TUMOR VOLUME IN NONPALPABLE PROSTATE-CANCER

Preoperative parameters were assessed for their usefulness in predicti ng tumor volume in 26 cases of nonpalpable prostate cancer. The number of positive biopsy cores was found to be the parameter which predicte d most accurately tumor volume in surgical specimens. All 14 patients with multiple positive cores had an index tumor of 0.5 cm(3) or more i n radical prostatectomy specimens. only six tumors with a single posit ive core were substantial. Three of the patient showed a serum level o f prostate specific antigen (PSA) of 4.0 ng/ml or more. The pathologic al stage and prostatectomy Gleason sum could not be predicted accurate ly by this variable (P > 0.05). To predict index tumor volumes of 1.0 cm(3) or greater, stepwise logistic regression analysis was conducted, and on the basis of the results it was possible to single out multipl e positive biopsies as the only significant variable. The number of po sitive biopsies appeared reliable for predicting tumor volume of surgi cal specimens in cases of nonpalpable disease. The presence of signifi cant tumors despite ''normal'' levels of PSA warrants further investig ation of variables that can predict such prostate cancers. An adequate model for predicting significant tumors in oriental male populations should be established using samples of larger size.