[848] Validation of a Gleason Score 7 Weighted Based on Proportion of Gleason 4 Component (Quantitative Gleason Score) as Predictor of Biochemical Recurrencee after Radical Prostatectomy

Fang-Ming Deng, Ruth Pe Benito, Nicholas Donin, Andrew Rosenkrantz, Ming Zhou, Hebert Lepor, Samir Taneja, Jonathan Melamed. NYU Langone Medical Center, New York, NY

Background: The risk for biochemical recurrence in Gleason score (GS) =7 prostate cancer (PCa) has been previously shown to vary according to proportion of 4 component (4+3> 3+4) and percentage of Gleason 4 to be a predictor of outcome. This has been to formulate a quantitative Gleason score that weights Gleason 4 differently from Gleason 3 to better predict PSA recurrence. In this study we validate a quantitative Gleason score in a large cohort of radical prostatectomy patients.
Design: From 2630 radical prostatectomy cases performed at our institute (1998-2010), Gleason 7 cases were identified and slides of the index tumor retrospectively reviewed by two GU pathologists. The GS was recorded based on the modified ISUP 2005 Gleason grading system and percentage of Gleason pattern 4 determined and used to calculate a qGS (= 2 x (3 x %GS3 + 4 x %GS4). Biochemical (PSA) recurrence was correlated with patient age, PSA at diagnosis, surgical margin status, clinical stage and qGS. The association between biochemical recurrence and qGS was tested using Cox proportional hazards regression analysis and adjusted for other risk factors.
Results: 952 patients (36.2%) with GS 7 PCa included Gleason 3 + 4 (n=775) and Gleason 4 + 3 (n=197). Patient age and PSA at diagnosis were 61 ± 7 years old and 9.0 ± 29.9 ng/ml; respectively. Pathologic stages included pT2 (n = 593, 62.3%) & pT3 (n = 358, 37.6%) with clinical follow up an average of 45 months. By univariate analysis qGS, status of surgical margin and seminal vesicle invasion correlated with biochemical recurrence (p<0.0001) for each. Patient age PSA at diagnosis, and extraprostatic extension were not associated with recurrence. qGS is still significantly associated with biochemical recurrence on multivariate analysis when adjusted for other risk factors (p < 0.0001). In comparison with traditional pathologic Gleason score (3 + 4 vs3 + 4), the qGS is a significant better predictor of biochemical recurrence {p= 0.48 vs p <0.0001 (Cox regression analysis in a backward stepwise selection model)}.
Conclusions: A quantitative Gleason Score (with weighting based on percentage of Gleason pattern 4 component) shows significant association with biochemical recurrence in patients with GS 7 prostate cancer. We suggest that adding the percentage of Gleason pattern 4 component or use of a qGS in the pathology report may improve prediction of PCa biochemical recurrent after radical prostatectomy.
Category: Genitourinary (including renal tumors)

Monday, March 4, 2013 2:45 PM

Proffered Papers: Section A, Monday Afternoon

 

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