Improved accuracy of biopsy Gleason score obtained by extended needle biopsy

：Objective To determinewhether an increased number of transrectal biopsy cores improves the accuracy of biopsyGleason score. Methods This study reviewed a total of 86 patients who were diagnosed asprostate cancer by transrectal needle biopsy and subsequently underwent radicalprostatectomy (RP) without neoadjuvant therapy.The rate of grading concordance betweenbiopsy and RP specimens was analyzed by dividing these patients into 2 groups according tothe biopsy cores:group A,46 patients who underwent transrectai biopsy sampling of 6cores,and group B,40 patients who underwent biopsy sampling of 13 cores. Results Theconcordance between prostate biopsy and radical prostatectomy Gleason score was 65.0%and34.8% for 13 core and 6 core biopsy,respectirely (P＜0.05).Furthermore,these findings tended to be moreprominent as the biopsy Gleason score was lower.Multivariate analysis identified thenumber of biopsy cores and percent of positive biopsy cores as independent predictors ofaccurate Gleason grading regardless of other parameters examined in this study. ConclusionExtended needle biopsy may increases the accuracy of biopsy Gleason score for assessingfinal prostate cancer grade. Key words: Prostatic neoplasms; Carcinoma; Biopsy,needle; Gleason score