Multiple cores of Gleason score 6 correlate with favourable findings at radical prostatectomy

Abstract

Objective: To establish whether the good prognosis of Gleason score 6 (GS6) is maintained in the setting of multiple involved cores.

Patients and methods: In total, 6156 men (from 1 April 2000 to 30 April 2007) with GS6 on biopsy underwent radical prostatectomy (RP) at our institution. The number of positive cores was correlated with the outcome at RP.

Results: More positive cores correlated with less organ-confined disease (P < 0.001), positive margins (P < 0.012), increasing RP grade (P < 0.001) and increased seminal vesicles/lymph node involvement (P = 0.012). For men with data available, the actuarial risk of being biochemically free of disease at 5 years was 93.2% when ≤6 cores were positive (812 men followed to 5 years) vs 89.1% if >6 cores were positive (41 men followed to 2 years) (P = 0.6). Although the predicted 'cure rate' of >75% probability of a tumour showing no evidence of biochemical recurrence at 10 years after RP was statistically different between cases with ≤6 vs >6 positive cores (P < 0.0001), the outcome in both groups was still favourable (90.5% vs 84%). Partin-like tables were generated factoring in the number of positive cores to predict organ-confined disease as a guide for urologists to perform nerve-sparing surgery. For example, with T1c disease, there was a ≥75% probability of organ-confined disease with one to three positive cores regardless of prostate-specific antigen (PSA) level, and the same probability was present with four to six positive cores and a PSA level of 0-4 ng/mL.

Conclusion: A low Gleason score on biopsy is a powerful prognostic finding, such that this favourable outcome is maintained even in the setting of multiple positive cores with GS6.