MRI-targeted Bx found superior to standard approach

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Practicing urologists should consider the potential value of performing a multiparametric MRI for a biopsy in men with suspected prostate cancer based on results from the PRECISION trial, says Veeru Kasivisvanathan, MRCS.

For men at clinical risk of prostate cancer, a diagnostic pathway including multiparametric magnetic resonance imaging (MRI) risk assessment and MRI-targeted biopsy is superior to a standard biopsy protocol, results of the PRECISION trial suggest.

By performing MRI-targeted biopsy only when multiparametric MRI results suggested an abnormal lesion, fewer men received a diagnosis of clinically insignificant prostate cancer versus transrectal ultrasound (TRUS)-guided biopsy, results show.

Conversely, the MRI-targeted biopsy group had more diagnoses of clinically significant prostate cancers versus the group that underwent TRUS-guided biopsy, according to results of the large, multinational, randomized study, recently presented at the European Association of Urology annual congress in Copenhagen, Denmark and published in the New England Journal of Medicine(March 18, 2018 [Epub ahead of print]).

Practicing urologists should consider the potential value of performing a multiparametric MRI for a biopsy in men with suspected prostate cancer based on these results, said first author Veeru Kasivisvanathan, MRCS, of University College London.

“It may improve their ability to diagnose clinically significant cancer, and may allow a proportion of men to avoid a biopsy altogether,” Dr. Kasivisvanathan said in an interview with Urology Times. “It will also reduce the early detection of clinically unimportant cancer, which will reduce the likelihood that men get over-treated.”

The findings follow publication of results from the PROMIS study in TheLancet showing that multiparametric MRI had significantly better sensitivity and negative predictive value compared to TRUS biopsy (Lancet 2017; 389:815-22).

Those results suggested MRI could be used to triage men with high serum PSA and potentially avoid about one-quarter of biopsies, PROMIS investigators wrote in their report.

“I think there are now two level 1 evidence trials, which provides enough evidence for us to say that we should be able to change clinical practice,” Dr. Kasivisvanathan said.

In the PRECISION study, Dr. Kasivisvanathan and colleagues randomized 500 men with elevated PSA or abnormal digital rectal exam to receive standard TRUS biopsy, or to receive multiparametric MRI with or without MRI-targeted biopsy.

Among the 252 men randomized to the MRI group, 71 (28%) did not have MRI findings suggestive of prostate cancer, and so did not undergo biopsy, according to the report on the study.

Despite fewer men undergoing biopsy in the MRI group, clinically significant cancers were detected in 38%, compared to just 28% in the TRUS biopsy group (p=.005), the report said.

Fewer men in the MRI-targeted biopsy group had a diagnosis of clinically insignificant cancer, with an adjusted difference of −13 percentage points (p<.001), investigators further reported.

Next: Dr. Loeb discusses findings

These findings provide compelling evidence supporting MRI prior to prostate biopsy, according to Stacy Loeb, MD, MSc, of NYU Langone Health.

“I hope that U.S. insurance companies will cover these tests from now on, which has been a major barrier in the past,” Dr. Loeb said in an interview.

The study randomized patients at 25 different sites in 11 countries, including a few centers within the United States, Dr. Loeb noted.

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“This was a pragmatic trial, so it was specifically designed to incorporate patients managed in a variety of settings including different MRI machines, registration techniques, and levels of clinician experience,” she said.

While the findings are encouraging, central review of some MRIs in the study showed only moderate agreement with the site radiologist’s biopsy decision (50 of 64 cases, 78%), suggesting that there is still room for improvement in the standardization of MRI reporting, Dr. Loeb said.

Another important consideration is that men with a negative MRI did not undergo biopsy, and therefore, further follow-up is important to examine outcomes in this group, she added.