[839] Prognostic Gleason Grade Grouping: Data Based on the Modifed Gleason Scoring System

Jonathan I Epstein, Patrick C Walsh, Alan W Partin. The Johns Hopkins Hospital, Baltimore

Background: There are some problems with reporting Gleason score (GS): 1) GS6 is typically the lowest grade assigned on biopsy (bx). However, GS ranges from 2-10, so men are concerned when told they have GS6 cancer on bx, logically but incorrectly assuming that their tumor is in the mid-range of aggressiveness. 2) Within the literature, GS3+4=7 & GS4+3=7 are often combined as GS7. 3) GS8-10 are also typically lumped together.
Design: We have previously shown that tertiary Gleason patterns in RP influence biochemical free survival rates (BFS), acting as an intermediary between grades. We identifed 8,039 men who underwent RP at our institutution since 2004 without tertiary patterns to study the sole effect of grade derived from the two predominant patterns.
Results: Of 4,510 GS2-6 tumor on bx, 1 had GS2-4 and 7 had GS5. Of 3,548 GS2-6 tumor at RP, 1 had GS2-4, and 44 had GS5. Therefore, 99.8% and 98.7% of biopsy & RP GS2-6 tumors were GS6, respectively, so cases were combined as GS2-6. Prognostic Grade Group (2-6; 3+4; 4+3; 8; 9-10) was among the strongest predictors of biochemical free survival (BFS) in multivariable models. At a median follow-up of two years (range 1-7), 2-year BFS rates for men with 3+3, 3+4, 4+3, 8, and 9-10 at bx were 97.4%, 90.0%, 84.7%, 73.1%, and 46.0% respectively (p<0.001); and 98.8%, 93.6%, 85.6%, 73.7%, and 48.9% (p<0.001), respectively, based on RP pathology.
Conclusions: GS 3+4=7 has a very favorable prognosis with an estimated 2-year BFS of 90.0% and 93.6% for bx and RP, respectively; these results warrant the designation of “moderately differentiated”. GS4+3=7 had a significantly worse prognosis than GS3+4=7. The current study shows GS9-10 has almost twice the risk of progression compared to GS8. We propose reporting Gleason grades, along with descriptive terminology, and including Prognostic Grade Groups which accurately reflect prognosis: GS2-6 (well-differentiated), Prognostic Grade Group I/V; GS3+4=7 (moderately differentiated), Prognostic Grade Group II/V; GS4+3=7 (moderately-poorly differentiated), Prognostic Grade Group III/V; GS8 (poorly differentiated), Prognostic Grade Group IV/V; and GS9-10 (undifferentiated), Prognostic Grade Group V/V. One would still report a case as “Gleason Score 5” or “Gleason score 6”, (rather than “Gleason Score 2-6”) along with Prognostic Grade Group I. The descriptive terms (i.e. well, moderately, etc.) would only be used along with GS in Pathology reports so that men could better understand their grade. Men will, for example, be reassured with a GS6 that their Prognostic Grade Group is I/V along with a description of the tumor as well-differentiated.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 2:45 PM

Platform Session: Section A, Monday Afternoon

 

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