Prevalence of a Tertiary Gleason Grade and Its Impact on Adverse Histopathologic Parameters in a Contemporary Radical Prostatectomy Series

Abstract

BackgroundThe presence of a tertiary Gleason grade (TGG) pattern in radical prostatectomy (RP) specimens has been described as associated with adverse pathology and a higher biochemical recurrence (BCR) rate after RP. ObjectiveTo assess the prevalence of a TGG in a contemporary, consecutive, single-centre RP series and its association with adverse pathology. Design, setting, and participantsFrom January to August 2007, 800 eligible patients (no prior neoadjuvant hormonal therapy) underwent RP for clinically localised prostate cancer (pCA) in our institution. The presence of the third most prevalent Gleason pattern was documented, regardless of whether it was better or worse than the two predominant Gleason grades. MeasurementsThe overall prevalence of a TGG was described. Uni- and multivariate logistic regression analyses tested the association between the presence of a TGG <5% versus ≥5% of the whole tumour volume and extracapsular extension (ECE), seminal vesicle invasion (SVI), positive surgical margins (PSM), and lymph node invasion (LNI). Subanalyses were performed to assess the impact of different TGGs at various Gleason scores. Results and limitationsA TGG was reported in 180 RP specimens (22.5%). In univariate analysis, the presence of a TGG ≥5% was significantly associated with ECE, SVI, PSM, and LNI (p<0.001). In multivariate analysis, a TGG ≥5% showed an independent association with ECE and PSM (p<0.05). Accordingly, in subanalyses, a significant association with adverse pathology was only documented if the amount of a TGG was at least 5% of the tumour volume. Our study is limited by the relatively low overall frequency of a TGG, thereby reducing the statistical expressiveness, especially for subanalyses. ConclusionsOur findings confirm the association of the presence of a TGG with adverse pathologic features. Further follow-up is needed to assess the prognostic impact of a TGG on the risk of BCR and overall survival following RP.