The impact of downgrading from biopsy Gleason 7 to prostatectomy Gleason 6 on biochemical recurrence and prostate cancer-specific mortality.

Gleason score (GS) is one of the most important prognostic indicators for prostate cancer (PC). Downgrading from biopsy (Bx) GS 7 to radical prostatectomy (RP) GS 6 occurs commonly, yet the impact on survival outcomes is unknown. We examined biochemical recurrence (BCR) and prostate cancer-specific mortality (PCSM) risk in a large cohort evaluated by a single group of expert urologic pathologists.

Of 23,918 men who underwent RP at our institution between 1984-2014, 10,236 with Bx and RP GS 6 or 7 without upgrading were included. The cohort was divided into three groups: group I (Bx and RP GS 6), N=6,923 (67.6%); group II (Bx GS 7 downgraded to RP GS 6), N=648 (6.3%); and group III (Bx and RP GS 7), N=2,665 (26.0%). BCR and PCSM risk were compared using Cox regression and competing-risk analyses adjusting for clinico-pathological variables.

At a median follow-up of 5 years (range:1-29), 992 men experienced BCR, and 95 died due to PC. BCR-free survival for downgraded men (group II) was better than for those with GS 7 on Bx and RP (group III, p <0.001), but worse than those with GS 6 on Bx and RP (group I, p <0.001). Downgrading was independently associated with BCR (AHR 1.87, p<0.0001), but not PCSM (AHR 1.65, p=0.636).

Downgrading from Bx GS 7 to RP GS 6 was an independent predictor of BCR, but not PCSM, and is likely due to the presence of minor amounts of Gleason pattern 4.

The Journal of urology. 2016 Nov 12 [Epub ahead of print]

Won Sik Ham, Heather J Chalfin, Zhaoyong Feng, Bruce J Trock, Jonathan I Epstein, Carling Cheung, Elizabeth Humphreys, Alan W Partin, Misop Han

Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Present address: Departments of Urology and Urological Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea., Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA., Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA; Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.