PROLIFERATIVE INDEX DETERMINATION IN PROSTATIC-CARCINOMA TISSUE - IS THERE ANY ADDITIONAL PROGNOSTIC VALUE GREATER-THAN THAT OF GLEASON SCORE, PLOIDY AND PATHOLOGICAL STAGE

Purpose: The proliferative index was evaluated as an additional progno stic variable in 244 radical prostatectomy specimens from patients wit h prostate cancer. This study was done on the grounds that this variab le has shown some promise as a prognostic tool in some other carcinoma s, for example breast cancer. Materials and Methods: The proliferative index was evaluated in 244 patients undergoing radical prostatectomy for clinically localized disease between January 1988 and August 1994. Proliferative index was determined using the Ki-67 antibody on fresh frozen tissue and MIB-1 on paraffin embedded tissues. Patients were di vided into 2 groups based on a proliferative index of less than 1 (185 ) or 1 or greater (59). Of the patients 49 (20%) had biochemical failu re (median 23 months to progressive prostate specific antigen elevatio n of 0.5 ng./ml. or more). Those whose treatment failed were also divi ded into 2 groups according to proliferative index: 32 of 185 (18%) wi th an index of less than 1 and 17 of 59 (27%) with an index of 1 or mo re. Gleason score and deoxyribonucleic acid ploidy status were also ev aluated in all patients and compared in multivariate regression analys is. Operative specimens were categorized as organ confined, specimen c onfined or margin positive. Results: The distribution according to mar gin status in the 2 groups (proliferative index less than 1 and 1 or m ore) was 40 versus 60% for organ confined, 67 versus 33% for specimen confined and 72 versus 28% for margin positive disease, respectively. The distribution of time to treatment failure in the 2 groups was not markedly different: 7.2 versus 9.4 months for margin positive, 10 vers us 14.5 months for specimen confined and 8.5 versus 12 months for orga n confined cancer, respectively. Conclusions: Multivariate analysis de monstrated that, although deoxyribonucleic acid ploidy seemed to corre late with more advanced disease, only Gleason sum and pathological T s tage reached statistical significance when evaluated against time to t reatment failure. A high proliferative index added little above the mo re traditional prognostic indicators of Gleason score, pathological st age and ploidy. Therefore, we question the value of proliferative inde x as a prognostic indicator using the aforementioned methodology in pr ostate cancer.