Significance of Gleason Grading of Low-Grade Carcinoma of the Prostate with Therapeutic Option of Active Surveillance

Abstract

Introduction: Active surveillance needs a precise grading diagnosis of a low-grade carcinoma of the prostate (Gleason score (GS) 6) within a small organ-confined tumor. However, how accurate is the gold standard of GS 6 in predicting a small pT2 carcinoma? To answer this question, we have analyzed grading systems in this study. Methods: Prostatic carcinomas in biopsy and corresponding radical prostatectomy (RP) specimens of 960 patients were graded by the Gleason system in which glandular fusions and nucleolar stage (prominence and location) were considered. Results: Using the modified Gleason grading, a high upgrading rate from the biopsy to RP specimens (GS 6–7) and in even 30% a non-organ-confined growth pattern (pT3) of GS 6 carcinoma in RP was found. When considering glandular fusion and the incorporation of the state of nucleoli within the Gleason grading, the agreement of score 6 between biopsy and RP specimens as well as the prediction of a pT2a tumor increased from about 80 to 90%. Conclusion: The combination of Gleason grading and grading of the nuclear and nucleolar features may help to identify patients eligible for active surveillance.