Should MRI Be Standard in Men Without a Previous Prostate Biopsy?

Gerald Chodak, MD


April 27, 2018

Hello. I'm Dr Gerald Chodak for Medscape. Today's topic is multiparametric MRI for diagnosing prostate cancer in men who have not had a previous prostate biopsy.

The New England Journal of Medicine[1] recently reported a study on 500 men randomized to undergo multiparametric MRI [with or without targeted biopsy] or [transrectal] ultrasound-guided biopsy. Biopsies were only performed in the MRI group if the Prostate Imaging-Reporting and Data System (PI-RADS) score was ≥ 3. Ultimately, 28% of the men did not undergo a biopsy in the MRI group.

The results were significant in the following ways. More men were diagnosed with clinically significant cancer in the MRI group (defined as having a Gleason score of ≥ 7). Fewer men with Gleason 6 cancer were diagnosed in the MRI group. This resulted in significant differences, both in finding more high-risk cancers and fewer low-risk cancers. High-risk cancers were detected in 38% of patients in the MRI group versus 26% in the standard group. Gleason 6 cancers were detected in 9% of patients in the MRI-targeted biopsy group compared with 22% in the ultrasound-guided biopsy group.

What does this tell us? Should multiparametric MRI become a standard for men who have not had a previous prostate biopsy? There are a couple of unresolved questions. First, 28% of the men did not undergo a biopsy in the MRI group, so it is unclear what percentage of the men with a high-risk cancer might have been missed. To find that information out would have required doing both methods of biopsy on the entire group. Another issue has to do with the outcome or the impact, because the same percentage of men underwent both active surveillance and aggressive therapy with radical prostatectomy in the two study groups. It will be hard to determine whether there is a long-term impact in terms of affecting survival or resulting in unnecessary therapy.

Nevertheless, this is an excellent study and it moves the dial along for MRI, which is becoming increasingly evident as a potential way to evaluate men. It looks like it's the best way to proceed if a man has had one negative ultrasound-guided biopsy. These data are providing support for doing multiparametric MRI in a man who has not had a previous prostate biopsy.

I look forward to your comments. Thank you.


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