ASSESSMENT OF PROSTATE-CANCER VOLUME USING ENDORECTAL COIL MAGNETIC-RESONANCE-IMAGING - A NEW PREDICTOR OF TUMOR RESPONSE TO NEOADJUVANT ANDROGEN SUPPRESSION THERAPY

Objectives. A clinical tool that can reliably assess prostate cancer r esponse to androgen suppression is lacking. This pilot study was desig ned to identify the potential clinical factor(s) that correlate with t umor response after neoadjuvant therapy. Methods. Twenty-one patients managed with definitive local therapy and neoadjuvant androgen suppres sion (median 3 months [range 2 to 7]) between 1995 and 1997 comprise t he study population. Fisher's exact test was used to test the signific ance of the proportion of patients with a given clinical factor and th e outcome of pathologic organ-confined disease. The clinical factors t ested included preoperative prostate-specific antigen, biopsy Gleason score, clinical stage, months of total androgen suppression, the chang e in the endorectal magnetic resonance imaging (erMRI)-defined stage, the change in erMRI-defined tumor, and the change in the erMRI-defined prostate volume during neoadjuvant androgen suppression. Results. All 21 patients had a decrease in the erMRI-determined prostate volume an d prostate-specific antigen during androgen suppression, whereas only 10 of 21 (48%) had a reduction in the erMRI-determined tumor volume. T here was a statistically significant increased proportion of patients with a decrease in the erMRI-determined tumor volume (P = 0.008) who h ad pathologic organ-confined disease. Conclusions. The results of this pilot study suggest that the changes in the erMRI-determined tumor vo lume occurring during androgen suppression may be predictive of the tu mor response. Validation in a larger prospective study is currently un derway. (C) 1998, Elsevier Science Inc. All rights reserved.