Login to Access Video or Poster Abstract: MP38-03
Sources of Funding: None

Introduction

Many urooncology centers currently precede prostate biopsy with a multiparametric MRI (mp-MRI) scan. However, there is a paucity of information on the exact predictive value of the mp-MRI in determining final histology based on the outcome of 12-core transrectal ultrasound (TRUS) guided prostate biopsy. Herein, we aim to decipher the predictive value of mp-MRI in detection and exclusion of prostate cancer using TRUS prostate biopsy.

Methods

UK multicentre study. Data from 592 patients scheduled to undergo mp-MRI and/or 12-core TRUS-guided prostate biopsy from January till September 2016 was reviewed retrospectively from a prospective database. Mp-MRIs were reported using the Prostate Imaging Reporting and Data System (PI-RADS). Only patients who had pre biopsy mp-MRIs followed by prostate biopsy were included in the study. 108 patient were excluded as they did not have mp-MRI or biopsy due to contraindications.

Results

Prebiopsy mp-MRIs followed by a 12-core TRUS-guided prostate biopsy were completed in 484 patients. The sensitivity and specificity of mp-MRI for prostate cancer detected on prostate biopsy were 92.6% and 74.4%, respectively. The negative predictive and positive predictive values of mp-MRI for prostate cancer detected on biopsy were 89.7% and 80.8%, respectively. 129 patients had a PI-RADS score of 5 on mp-MRI, with prostate cancer detected in 92%(n=119) of patients on biopsy. The incidence of Gleason scores 6,7,8 and 9 in patients with PI-RADS 5 were 15.9%(n=19), 51.2%(n=61), 6.7%(n=8) and 26%(n=31), respectively. 117 patients had a PI-RADS score of 4 on mp-MRI, with prostate cancer detected in 53.8%(n=63) of patients on biopsy. The incidence of Gleason scores 6,7,8 and 9 in patients with PI-RADS 4 were 60%(n=36), 33.3% (n=21), 4.7% (n=3) and 1.5% (n=1), respectively. 153 patients had a PI-RADS score of 3 on mp-MRI, with prostate cancer detected in 29% (n=45) of patients on biopsy. The incidence of Gleason scores 6,7 and 9 cancers in patients with PI-RADS score of 3 were 68% (n=31), 26.6% (n=12) and 4.4% (n=2), respectively. Overall there was a statistically significant association between patients with PIRADS scores ≥3 and cancer positive biopsies (p=0.001)

Conclusions

Mp-MRI has a high predictive value for both diagnosing and excluding prostate cancer. Patients with PI-RADS scores ≥3 had a significant association with detection of prostate cancer on biopsy. These findings could aid in guiding follow-up protocols in men suspected of prostate cancer.

Funding

None