Is mpMRI ready for prostate Ca screening?

August 1, 2016

"Avoiding unnecessary biopsies should be a high-priority goal for us all," writes J. Brantley Thrasher, MD.

J. Brantley Thrasher, MDDr. Thrasher,

 

Ahmed et al recently presented results of a trial examining the use of multiparametric MRI (mpMRI) as a triage test to avoid biopsy in men with an elevated PSA. Men from 11 centers in the United Kingdom underwent mpMRI using a 1.5 Tesla magnet with no endorectal surface coil, followed by both TRUS biopsy and template mapping biopsy. The authors found that mpMRI had a high sensitivity and high negative predictive value and performed much better than TRUS biopsy in identifying clinically significant cancers.

They concluded that mpMRI could be used as a screening test to identify men who might avoid a primary biopsy.

This abstract piqued my interest, and I am sure I’m not alone. I would love to have a cost-effective, sensitive, and specific screening test to help avoid unnecessary biopsies. The rate of post-biopsy infections due to resistant Escherichia coli has ranged from 13%-52% in various series (J Urol 2012; 187:1275-9; Eur Urol 2012; 62:453-9; Urology 2011; 78:1235-9). Studies such as this one will hopefully help us shift to a more focused way of identifying men who truly need to undergo a targeted biopsy.

However, many questions remain. Presently, third-party payers balk at reimbursing for mpMRI-directed biopsies prior to an initial TRUS biopsy. If these results can be reproduced in a large North American multi-institutional trial, might that change? Would the use of a 3 Tesla magnet change the positive predictive value of mpMRI? If the definition of clinically significant cancer were changed to Gleason ≥3+4, would the results have been different? A recent report of the MURIELLE study group (using slightly different selection criteria and definitions of clinically significant cancer) found no difference in the identification of clinically significant cancer between targeted and systematic biopsies (J Urol April 12, 2016 [Epub ahead of print]).

I certainly applaud the authors for their study and look forward to further research in this area. Avoiding unnecessary biopsies should be a high-priority goal for us all. If these results can be reproduced by others and the remaining questions clarified, we may be on track to meet that goal.

More on Prostate Cancer:

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Low concordance with NCCN surveillance guide seen

Adjuvant chemo well tolerated in high-risk PCa patients

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