AUA 2019: Negative Multi-Parametric MRI Accurately Predicts the Absence of Clinically Significant Prostate Cancer

Chicago, IL (UroToday.com) Multiparametric magnetic resonance imaging (mpMRI) has gained an increasingly large role in the evaluation of patients undergoing evaluation for prostate cancer. While its role in men with a previous negative prostate biopsy is well accepted, the PRECISION trial clearly established that mpMRI provides valuable information in the management of men suspected of having prostate cancer, prior to the initial prostate biopsy. One of the remaining concerns is the negative predictive value of prostate mpMRI – that is, how confident can we be that a patient does not have clinically significant prostate cancer if they have a negative mpMRI?

The authors performed a retrospective analysis of patients who underwent mpMRI followed by targeted and template biopsy between January 2015 and July 2018 at their institution. The authors utilized the Pi-RADs v2 approach to interpret mpMRIs and performed targeted biopsy of all lesions with Pi-RADs score greater than 3 (on a 5 point scale). The authors defined clinically significant prostate cancer as Gleason score 7 or greater (GGG ≥2) and utilized standard 12-core template biopsy as the “gold standard” to assess the negative predictive value of mpMRI.

The authors identified 592 men who underwent mpMRI with targeted and systematic biopsies. Utilizing 12-core template biopsy as the “gold standard”, mpMRI demonstrated a high negative predictive value (92.3%, 95% CI 898-94.8%). Further, the authors found that mpMRI was more likely to detect clinically significant prostate cancer than 12-core template biopsy (27.5% vs 22.3%, p=0.002).

Additionally, there was relatively high agreement in histological grading between the two approaches, with only 5.7% of patients found to have clinically significant disease on systematic biopsy with insignificant disease on fusion biopsy. Nearly twice as many (9.3%) had significant disease on fusion biopsy but only insignificant disease diagnosed on standard systematic biopsy.

This abstract provides valuable data which may reassure physicians that patients with negative mpMRI are unlikely to harbour clinically significant prostate cancer. It should be noted that, despite the apparent objectivity of the Pi-RADs scoring system, there remains significant variation in the interpretation of prostate mpMRI. Thus, findings from one center or group of radiologists may not necessarily be generalizable to other institutions or settings.

Presented by: Spencer Hart, MD, Loyola University Medical Center

Co-authors: Chirag Doshi, Thomson Tai, Ryan Dornbier, Cara Joyce, Alex Gorbonos, Michael Woods,Marcus Quek, Robert Flanigan, Gopal Gupta

Written by: Christopher J.D. Wallis, Urology Resident, University of Toronto @WallisCJD at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois

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