Multiparametric Magnetic Resonance Imaging Should Be Preferred Over Digital Rectal Examination for Prostate Cancer Local Staging and Disease Risk Classification

Abstract

Objective: To assess the impact of multiparametric magnetic resonance imaging (mp-MRI) local tumor staging on prostate cancer risk stratification and choice of treatment.

Materials and methods: Prostate cancer patients, newly diagnosed from 2017 to 2018 at 7 Dutch teaching hospitals were included. Risk group classification was done twice, using either digital rectal examination (DRE) or mp-MRI information. Risk group migration and rates of treatment intensification associated with mp-MRI upstaging were established. Diagnostic accuracy measures for the detection of nonorgan-confined disease (stage ≥T3a), for both DRE and mp-MRI, were assessed in patients undergoing robot-assisted radical prostatectomy.

Results: A total of 1683 patients were included. Upstaging due to mp-MRI staging occurred in 493 of 1683 (29%) patients and downstaging in 43 of 1683 (3%) patients. Upstaging was associated with significant higher odds for treatment intensification (odds ratio [OR]: 3.5 95% confidence interval [CI] 1.9-6.5). Stage ≥T3a on mp-MRI was the most common reason for risk group upstaging (77%). Sensitivity for the detection of stage ≥T3a was higher for mp-MRI compared to DRE (51% vs 12%, P <.001), whereas specificity was lower (82% vs 97%, P <.001). Mp-MRI resulted in a significantly higher cumulative rate of true positive and true negative stage ≥T3a predictions compared with DRE (67% vs 58%, P <.001).

Conclusion: Use of mp-MRI tumor stage for prostate cancer risk classification leads to upstaging in 1 of 3 patients. Mp-MRI enables superior detection of nonorgan-confined disease compared with DRE, and should be the preferred tool for determining clinical tumor stage.