Pathological concordance between prostate biopsies and radical prostatectomy using transperineal sector mapping biopsies: Validation and comparison with transrectal biopsies

Background/Aims/Objectives: Our aim was to evaluate the accuracy of systematic transperineal sector mapping biopsy (TPSMB) in predicting Gleason score (GS) at radical prostatectomy (RP), to compare its accuracy with standard transrectal ultrasound-guided biopsies (TRUS) and to establish the clinical impact of discordance between biopsies and RP on subsequent surgical management. Methods: Two hundred fifty-five patients from 2008 to 2013 who underwent RP following TPSMB (n = 204) or TRUS (n = 51), were included in this retrospective multi-institutional study. Concordance between biopsies and RPs GS was assessed both as percentages and with Cohen's Kappa coefficient. All mismatches between biopsies and RP were assessed for significance by 3 urologists using the Delphi method. Results: No differences were present among the groups. Concordance between biopsy and RP GS was 75.49% for TPSMB and 64.70% for TRUS. Kappa coefficient was 0.42 and 0.39 respectively. The Delphi method showed lower clinical impact of GS discordances for TPSMB with 7.8% of patients having significant change, thus being potentially more suitable for other treatment modalities, compared to TRUS (13.7%). Conclusions: TPSMB had a higher accuracy for predicting the GS grade at RP showing superior GS concordance compared with standard TRUS. TPSMB provides an effective technique for systematic prostate biopsy to evaluate overall prostate cancer GS.