To assess the negative predictive value (NPV) of multi-parametric MRI (mpMRI) for detection of prostate cancer (PCa) in routine clinical practice, and to identify characteristics of patients for whom mpMRI fails to detect high-grade (Gleason ≥7) disease.
We reviewed our prospectively maintained database of consecutive men who received prostate mpMRI at our institution, interpreted by a clinical practice of academic radiologists. Between January 2012 and December 2015, 84 men without any MR suspicious regions (MSRs) according to prior institutional classification, or with PI-RADS 1-2 lesions according to the PI-RADS system, underwent standard template transrectal ultrasound-guided (TRUS) prostate biopsy. Using these biopsy results, we calculated the NPV of mpMRI for detection of PCa, and identified patient risk factors for having Gleason ≥7 PCa on biopsy.
High-grade (Gleason ≥7) PCa was found on TRUS biopsy in 10.3% of biopsy-naïve patients (NPV=89.7%), 16.7% of patients with previous negative biopsy (NPV=83.3%), and 13.3% of patients on active surveillance (NPV=86.6%). On multivariate analysis, the Prostate Cancer Prevention Trial Risk Calculator (PCPTRC) estimated risk for high grade PCa (as a continuous variable) was a significant independent predictor for high grade PCa on biopsy (OR 1.01, p<0.01).
Men with negative mpMRIs interpreted in a routine clinical setting have a significant risk of harboring Gleason ≥7 PCa on standard 12-region template biopsy, independent of indication. Standard template TRUS prostate biopsy should still be recommended for patients with negative mpMRI, particularly those with elevated PCPTRC estimated risk of high grade PCa.
Urology. 2016 Nov 11 [Epub ahead of print]
Robert S Wang, Eric H Kim, Joel M Vetter, Kathryn J Fowler, Anup S Shetty, Aaron J Mintz, Niraj G Badhiwala, Robert L Grubb, Gerald L Andriole
Division of Urologic Surgery, Washington University School of Medicine, St. Louis, MO, USA., Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA.