Predictive Factors and Oncologic Outcome of Downgrade to Pathologic Gleason Score 6-7 after Radical Prostatectomy in Patients with Biopsy Gleason Score 8-10

Gleason score (GS) 8-10 is associated with adverse outcomes in prostate cancer (PCa). However, biopsy GS (bGS) may be upgraded or downgraded post-radical prostatectomy (RP). We aimed to investigate predictive factors and oncologic outcomes of downgrade to pathologic GS (pGS) 6-7 after RP in PCa patients with bGSs 8-10. We retrospectively reviewed clinical data of patients with bGS 8 undergoing RP. pGS downgrade was defined as a pGS 7 from bGS 8 post-RP. Univariate and multivariate cox regression analysis, logistic regression analysis, and Kaplan-Meier curves were used to analyze pGS downgrade and biochemical recurrence (BCR). Of 860 patients, 623 and 237 had bGS 8 and bGS 9, respectively. Post-RP, 332 patients were downgraded to pGS 7; of these, 284 and 48 had bGS 8 and bGS 9, respectively. Prostate-specific antigen (PSA) levels; clinical stage; and adverse pathologic features such as extracapsular extension, seminal vesicle invasion and positive surgical margin were significantly different between patients with pGS 7 and pGS 8. Furthermore, bGS 8 (odds ratio (OR): 0.349, p < 0.001), PSA level < 10 ng/mL (OR: 0.634, p = 0.004), and cT3a (OR: 0.400, p < 0.001) were identified as significant predictors of pGS downgrade. pGS downgrade was a significant positive predictor of BCR following RP in patients with high bGS (vs. pGS 8, hazard radio (HR): 1.699, p < 0.001; vs. pGS 9, HR: 1.765, p < 0.001). In addition, the 5-year BCR-free survival rate in patients with pGS downgrade significantly differed from that in patients with bGS 8 and 9 (52.9% vs. 40.7%, p < 0.001). Among patients with bGS 8, those with bGS 8, PSA level < 10 ng/mL, and cT3a may achieve pGS downgrade after RP. These patients may have fewer adverse pathologic features and show a favorable prognosis; thus we suggest that active treatment is needed in these patients. In addition, patients with high-grade bGS should be managed aggressively, even if they show pGS downgrade.