Gleason score concordance on biopsy-confirmed prostate cancer : is pathological re-evaluation necessary prior to radical prostatectomy?

Level of Evidence 4 What's known on the subject? and What does the study add? Following the updated Gleason grading system in 2005 by the International Society of Urological Pathologists (ISUP), studies demonstrated improved prediction of biochemical (PSA) progression-free outcome by needle core biopsy specimens. To our knowledge, no studies have investigated the impact of the modified grading system on inter-laboratory agreement of biopsy Gleason score (bGS) and the effect of re-evaluation on accuracy in predicting the true underlying histopathology. We report that when biopsy re-evaluation resulted in a change in bGS, there was a marked improvement in the prediction of underlying pathology as determined by prostatectomy Gleason score suggesting that when outside referral of bGS results in an equivocal clinical decision, biopsy re-evaluation can provide clarity on the true underlying tumour architecture. OBJECTIVES center dot Gleason sum from prostate biopsy (bGS) is an important tool in classifying severity of disease, ultimately influencing clinical management. center dot Commonly, pathology specimens are re-evaluated internally prior to surgery. center dot We evaluate agreement of bGS with prostatectomy Gleason sum (pGS) and the impact of re-grading on prediction of true underlying tumor architecture. MATERIALS AND METHODS center dot Retrospective analysis of men who underwent robotic-assisted radical prostatectomy (RARP) by two surgeons from 2005-2009. Initial transrectal ultrasound (TRUS) biopsy demonstrated carcinoma at an outside lab. Specimens were re-evaluated by our GU pathologists prior to surgery. Biopsy data were correlated with pGS. center dot Kappa (kappa) statistics for agreement and linear regression analyses were used for categorical variables. Coefficient of concordance was used for continuous variables. RESULTS center dot 100 patients had 331 positive biopsies. Agreement (kappa) for bGS between outside labs and our pathologists was 0.55 (p < 0.001). center dot Internal read was twice as likely to upgrade vs. downgrade outside bGS (23% vs. 11%). center dot When re-evaluation resulted in a change in bGS, agreement with pGS was kappa = 0.29, vs. kappa = -0.04 for agreement of initial (outside) bGS with pGS. center dot When no change was made to bGS, agreement with pGS was kappa = 0.40 (p < 0.001). CONCLUSION center dot Good reproducibility seen between outside labs and our institution on bGS. Internal pathology re-reads correlated better with pGS than original community bGS. When re-reads result in a change in bGS, there is a marked improvement in prediction of underlying tumor architecture confirming the value of re-evaluating all external biopsies prior to definitive surgery.