DOES PATHOLOGICAL GLEASON SCORE RE-REVIEW BY A MODERN PATHOLOGIST IMPROVE RISK STRATIFICATION RELATIVE TO HISTORICAL GLEASON SCORE?

Abstract

INTRODUCTION AND OBJECTIVE: Early detection, stage migration, and emphasis on health related quality of life has led to increasing interest in focal therapy for prostate cancer (PCa). Advocates attempt to map prostate tumors in order to limit their patient population to those with unifocal disease. Unfortunately, no descriptive studies evaluating single focus prostate cancer have been performed and little is known regarding the unique biology of this disease. The objective of this study is to characterize the clinicopathologic behavior of unifocal PCa in comparison to its multifocal counterpart. METHODS: The Center for Prostate Disease Research (CPDR) database was queried for all prostatectomy specimens obtained from 1994 to 2004. All specimens were analyzed at the Armed Forces Institute of Pathology utilizing whole mount and 2 mm step sectioning. Tumors were comprehensively mapped to include number of tumor foci and calculation of total tumor volume. Patients with single focus PCa were compared to those demonstrating multifocal disease. Primary outcomes were pathologic stage and biochemical recurrence, while secondary outcomes were Gleason sum and total tumor volume. A p-value of <0.05 was considered statistically significant using the chi-square, Fisher exact, and student’s T-test. RESULTS: A total of 1012 prostatectomies were examined with 109 (10.7%) demonstrating a single focus of PCa. Median patient age was 60 in the unifocal and 61 in the multifocal cohorts. Median PSA was 10 for the unifocal and 7.4 for the multifocal cohorts. Median total tumor volume was 5.2 cc for unifocal and 4.2 cc for multifocal disease. The unifocal cohort Gleason sums were 2-6 in 51%, 7 in 31.6%, and 8-10 in 17.3%. The multifocal cohort Gleason sums were 2-6 in 56.8%, 7 in 29.9%, and 8-10 in 10.1%. Extraprostatic extension was noted in 56.0% of cases with unifocal and 36.1% of cases with multifocal disease. In total, 27% of unifocal and 15.5% of multifocal disease had biochemical recurrence. Of the patients with organ confined (pT2) disease, 6.4% of unifocal and 5.2% of multifocal disease had a PSA recurrence. The frequency of single focus CaP stratified by year of surgery was: 19931996 (17%), 1997-2000 (9.4%), 2001-2004 (8.6%). CONCLUSIONS: Unifocal prostate cancer is a more aggressive entity than its multifocal counterpart. PSA, Gleason sum, total tumor volume, extracapsular disease, and biochemical recurrence were significantly higher in the unifocal population. With intensive prostate cancer screening the incidence of single focus prostate cancer has decreased.