Introduction

Accurate prediction of Gleason score (GS) after radical prostatectomy (RP) is important to determine treatment plans. However, 20-60% of patients with biopsy GS 6 are upgraded to GS 7 or more postoperatively. In this study, we evaluated whether Prostate Imaging Report and Data System version 2 (PI-RADSv2) has a role to predict upgrading after RP for patients with biopsy GS 6

Methods

We retrospectively reviewed 443 patients who underwent magnetic resonance imaging (MRI) and RP for prostate cancer with biopsy GS 6 between January 2011 and December 2013. Preoperative clinical parameters (prostate specific antigen [PSA], prostate volume, PSA density, number of positive core and maximum percentage of cancer per core), PI-RADS v2 score and pathologic GS were examined. Multivariate logistic regression was used to analyze predictive factors of upgrading after RP. Receiver operating characteristic (ROC) curves were used to analyze the predictive accuracies of multivariate logistic regression models and areas under the curves (AUCs) of ROC curves were compared.

Results

Of 443 patients with biopsy GS 6, GS upgrading was identified in 297 (67.0%) patients (GS7, n=273 and GS8-10, n=24) following RP. PI-RADS v2 score 1-3, and 4-5 were identified in 157 (25.4%) and 286 (64.6%) patients, and upgrading rate after RP were 54.1% and 74.1%, respectively (p < 0.001). On multivariate analysis, PSA density > 0.16 ng/ml2, number of positive core ? 2, maximum % cancer/core >20% and PI-RADS v2 score 4-5 were predictive factors of upgrading following RP (all p < 0.05). When predictive accuracies of multivariate models were compared using AUC from ROC curves, model 2 (PI-RADS v2 score 4-5 along with model 1) was found to have significantly higher accuracy then model 1(PSA density > 0.16 ng/ml2, number of positive core ? 2 and maximum % cancer/core >20%) (0.729 vs 0.703, p = 0.041)

Conclusions

PSA density > 0.16 ng/ml2 , number of positive core ? 2 and maximum percentage of tumor length in a core > 20% are independent predictors of GS upgrading as preoperative variables. PI-RADSv2 4-5 confer an increased risk for GS upgrading that it may be used as a preoperative image tool to establish treatment decision.

Funding

none