EAU 2019: Discussion: Fast Bi-Parametric MRI vs Multi-Parametric MRI and TRUS-Biopsy for Detecting Clinically Significant Prostate Cancer

Barcelona, Spain (UroToday.com) Dr. Alberto Briganti provided an overview and discussion following Dr. Barentsz presentation of fast bpMRI for detection of prostate cancer. Dr. Briganti notes that there are several clear strengths of this study:

  • There is a clinical need to reduce costs, time, and side effects of prostate MRI while maintaining high NPV for clinically significant prostate cancer
  • Thanks to the fast bpMRI improvements, MRI could be potentially implemented more efficiently into early prostate cancer diagnosis and screening programs
  • This is a prospective, multi-center study in the landscape of many previous retrospective studies
  • Centralized readings of MRI and biopsy specimens
  • Use of high-quality standards
However, according to Dr. Briganti, this study does have limitations.
  • First, this study was not designed to assess comparisons between mpMRI and fast bpMRI, as it was part of the larger 4M study1. As part of this, the decision on biopsy was based on the mpMRI, not bpMRI.
  • Second, there is an increase in PI-RADS 3 lesions, with likely difficult generalizability of these findings. In the mpMRI assessment, the PI-RADS 3 rate was 6.4% and 11.2% in the fast bpMRI assessment. This represents an absolute increase of 4.8%, or 75% relative increase. If this 75% relative increase is extrapolated to PROMIS, PRECISION, and MRI-FIRST, the result would be an absolute increase of PI-RADS 3 lesions by 16-21%. As Dr. Barentsz has mentioned previously, the goal is for a PI-RADS 3 detection rate of <15%.  
  • Third, there is an increase in the number of biopsies and biopsy-related costs. Fast bpMRI resulted in a 2.2% increase in biopsies – if this were extrapolated to PROMIS, PRECISION, and MRI-FIRST, Dr. Briganti notes that this would result in an extra 7.4-10% biopsies.
  • Fourth, Dr. Briganti questions the quality of the imaging/interpretation considering the specificity of bpMRI was 66%. While comparable to mpMRI, it is not great.
  • Finally, Dr. Briganti has general concerns in the MRI literature about the agreement between readers. In the current study, with expert readers, fast bpMRI had 90% reader agreement, which his quite good – however, previous studies have poor reader agreement with kappa levels as low as 0.29.
Posing a rhetorical question, Dr. Briganti asks “Is fast bpMRI ready to replace mpMRI in all patients?”

(Maybe) yes, but only in Nijmegen


Presented by: Alberto Briganti, IRCCS Ospedale San Raffaele, Milan, Italy 

Written by: Zachary Klaassen, MD, MSc – Assistant Professor of Urology, Georgia Cancer Center, Augusta University - Medical College of Georgia Twitter: @zklaassen_md at the 34th European Association of Urology (EAU 2019) #EAU19 conference in Barcelona, Spain, March 15-19, 2019.

References:
  1. van der Leest M, Cornel E, Israel B, et al. Head-to-head comparison of transrectal ultrasound-guided prostate versus multiparametric prostate resonance imaging with subsequent magnetic resonance-guided biopsy in biopsy-naïve men with elevated prostate-specific antigen: A Large Prospective multicenter study. Eur Urol. 2018 Nov 23 [Epub ahead of print].
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