Improved Accuracy for Predicting the Gleason Score of Prostate Cancer by Increasing the Number of Transrectal Biopsy Cores

Abstract

Introduction: The objective of this study was to determine whether an increased number of transrectal biopsy cores improves the accuracy of the biopsy Gleason score. Materials and Methods: This study included a total of 225 patients who were diagnosed as having prostate cancer by transrectal needle biopsy and subsequently underwent radical prostatectomy (RP) without neoadjuvant therapy. The rate of grading concordance between biopsy and RP specimens was analyzed by dividing these patients into 2 groups as follows: group A, 107 patients who underwent transrectal biopsy sampling of 9 cores or less (median 8 cores), and group B, 118 patients who underwent biopsy sampling of 10 cores or more (median 12 cores). Results: Concordance between the biopsy and RP Gleason scores in group A (53.3%) was significantly lower than that in group B (69.5%). Upgrading of the biopsy Gleason score in group A (38.3%) was significantly more frequent than that in group B (21.2%). Furthermore, these findings tended to be more prominent as the biopsy Gleason score was lower. Multivariate analysis identified the number of biopsy cores and percent of positive biopsy cores as independent predictors of accurate Gleason grading regardless of other parameters examined in this study. Conclusion: These findings suggest that obtaining a greater number of biopsy cores contributes to improving the accuracy of the biopsy Gleason score for predicting the RP Gleason score; therefore, extended sampling of biopsy cores could provide optimal guidance to determine the therapeutic options in patients with prostate cancer.