Abstract
The 2005 International Society of Urological Pathology (ISUP) modified Gleason grading system was further amended in 2014 with the establishment of grade groupings (ISUP grading). This study examined the predictive value of ISUP grading, comparing results with recognised prognostic parameters. Of 3700 men undergoing radical prostatectomy (RP) reported at Aquesta Pathology between 2008 and 2013, 2079 also had a positive needle biopsy available for review. We examined the association between needle biopsy 2014 ISUP grade and 2005 modified Gleason score, tumour volume, pathological stage of the subsequent RP tumour, as well as biochemical recurrence-free survival (BRFS). The median age was 62 (range 32-79 years). Median serum prostate specific antigen was 5.9 (range 0.4-69 ng/mL). For needle biopsies, 280 (13.5%), 1031 (49.6%), 366 (17.6%), 77 (3.7%) and 325 (15.6%) were 2014 ISUP grades 1-5, respectively. Needle biopsy 2014 ISUP grade showed a significant association with RP tumour volume (p < 0.001), TNM pT and N stage (p < 0.001) and BRFS (p < 0.001). Multivariate analysis using Cox proportional hazards regression model showed serum prostate specific antigen (PSA) at the time of diagnosis and ISUP grade >2 to be significantly associated with BRFS. This study provides evidence of the prognostic significance of ISUP grading for thin core needle biopsy of prostate.