Prostate cancer upgrading or downgrading of biopsy Gleason scores at radical prostatectomy: prediction of “regression to the mean” using routine clinical features with correlating biochemical relapse rates

Abstract

Recommendations for managing clinically localized prostate cancer are structured around clinical risk criteria, with prostate biopsy (PB) Gleason score (GS) being the most important factor. Biopsy to radical prostatectomy (RP) specimen upgrading/downgrading is well described, and is often the rationale for costly imaging or genomic studies. We present simple, no-cost analyses of clinical parameters to predict which GS 6 and GS 8 patients will change to GS 7 at prostatectomy. From May 2006 to December 2012, 1590 patients underwent robot-assisted radical prostatectomy (RARP). After exclusions, we identified a GS 6 cohort of 374 patients and a GS 8 cohort of 91 patients. During this era, >1000 additional patients were enrolled in an active surveillance (AS) program. For GS 6, 265 (70.9%) of 374 patients were upgraded, and the cohort included 183 (48.9%) patients eligible for AS by the Prostate Cancer Research International Active Surveillance Study (PRIAS) standards, of which 57.9% were upgraded. PB features that predicted a >90% chance of upgrading included ≥ 7 cores positive, maximum foci length ≥ 8 mm in any core, and total tumor involvement ≥ 30%. For GS 8, downgrading occurred in 46 (50.5%), which was significantly higher for single core versus multiple cores (80.4% vs 19.6%, P = 0.011). Biochemical recurrence (BCR) occurred in 3.4% of GS 6 upgraded versus 0% nonupgraded, and in GS 8, 19.6% downgraded versus 42.2% nondowngraded. In counseling men with clinically localized prostate cancer, the odds of GS change should be presented, and certain men with high-volume GS 6 or low-volume GS 8 can be counseled with GS 7-based recommendations.

Keywords

• biopsy; downgrade; gleason score; prostate cancer; upgrade