Gleason score 6 prostate cancer is not always harmless

Concordance Between Biopsy and Radical Prostatectomy Gleason Scores: Evaluation of Determinants in a Large-Scale Study of Patients Undergoing RARP in Belgium

To determine whether Gleason scores were concordant between prostate biopsies (bGS) and the definitive resection specimen (pGS) excised with robot-assisted radical prostatectomy (RARP); to identify clinical and pathological factors that might predict upgrading; and to evaluate how upgrading affected outcome. Between 2009 and 2016, 25 Belgian centers participated in collecting prospective data for patients that underwent RARP. We analyzed the concordance rate between the bGS and the pGS in 8021 patients with kappa statistics, and we compared concordance rates from different centers. We assessed the effect of several clinical and pathological factors on the concordance rate with logistic regression analysis. The concordance rate for the entire population was 62.9%. Upgrading from bGS to pGS occurred in 27.3% of patients. The number of biopsies was significantly associated with concordance. Older age (>60 y), a higher clinical T stage (≥cT2), a higher PSA value at the time of biopsy (>10 ng/ml), and more time between the biopsy and the radical prostatectomy were significantly associated with a higher risk of upgrading. Positive margins and PSA relapse occurred more frequently in upgraded patients. Center size did not significantly affect the concordance rate (p = 0.40).This prospective, nationwide analysis demonstrated a Gleason score concordance rate of 62.9%. Upgrading was most frequently observed in the non-concordant group. We identified clinical and pathological factors associated with (non)-concordance. Upgrading was associated with a worse oncological outcome. Center volume was not associated with pathological accuracy.