A Comparative Histopathologic Analysis of Prostatic Carcinomas by Conventional and 2005 ISUP Modified Gleason Systems

Abstract

Introduction: The Gleason system is one of the most widely used systems for grading prostatic carcinomas. With several revisions since its inception, earlier studies have found poor levels of agreement between core biopsy and radical prostatectomy specimens. However, the adoption of the 2005 International Society of Urological Pathology (ISUP) Modified Gleason System has noted not only a better level of agreement between core biopsies and radical prostatectomy specimens but in addition, noted a trend towards upgrading of tumours when compared with the Conventional Gleason system. Aim: The aim of this study is to analyse the implications of 2005 ISUP Modified Gleason System on grading of prostatic carcinomas. Materials and Methods: The study involved histopathologic analysis of 30 needle core biopsy and transurethral resection of prostate specimens which were graded by two independent observers, using the Conventional Gleason System and 2005 ISUP Modified Gleason System. This study was conducted between January 2014 to May 2016. Results: Number of cases with Gleason score 6 reduced by 40% and number of cases with Gleason score 9 and 10 increased by 46.73% and 17% respectively. The overall number of high grade tumours (8-10) increased by 57.03% between reviews. Conclusion: This analysis showed a significant change in scores between the Conventional and 2005 ISUP Modified Gleason Systems. The result is likely due to expansion of the definition of Pattern 4 in the Modified Gleason system and elimination of the 5% threshold for reporting of higher grade tumours.

Keywords

• neoplasm grading
• prostatic neoplasms
• transurethral resection of prostate