PD30-05 THE IMPACT OF DOWNGRADING FROM BIOPSY GLEASON SCORE 7 TO RADICAL PROSTATECTOMY GLEASON SCORE 6 ON BIOCHEMICAL RECURRENCE

INTRODUCTION AND OBJECTIVES: Downgrading from biopsy Gleason score (Bx GS) 7 to radical prostatectomy (RP) GS 6 could occur if tangentially-sectioned small glands of Gleason 3 on Bx are overgraded as pattern 4, or alternatively if small foci of pattern 4 in the RP specimen are not recorded or unsampled deeper within the paraffin block. In the later scenario, downgraded men might have a worse prognosis than those with Bx and RP GS 6. We investigated whether there was a difference in biochemical recurrence-free survival (BCRFS) rates based on downgrading status. METHODS: Among 24,536 men with RP between 1984 and 2015, we reviewed 15,586 men (group I [Bx GS 6 to RP GS 6]1⁄4 10,538 [67.6%], group II [Bx GS 7 to RP GS 6]1⁄4 941 [6.0%], and group III [Bx GS 7 to RP GS 7]1⁄4 4,107 [26.4%]). For men with complete follow-up, the log-rank test was used to compare BCRFS between the groups. Cox regression analyses were used to determine the impact of downgrading on BCR. RESULTS: At a median follow-up of 5 years (IQR 2-12), 1,025 men experienced BCR. There were significant differences in age, preoperative prostate-specific antigen (PSA), year of surgery, clinicopathological stage, and positive surgical margin (PSM) between groups (all p