MRI-Fusion Biopsy Benefits PCa Active Surveillance Patients

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Targeting PI-RADS 4 and 5 lesions for confirmatory biopsy improves detection of clinically significant cancer.
Targeting PI-RADS 4 and 5 lesions for confirmatory biopsy improves detection of clinically significant cancer.
The following article is part of conference coverage from the 2017 American Urological Association meeting in Boston. Renal and Urology News' staff will be reporting live on medical studies conducted by urologists and other specialists who are tops in their field in kidney stones, prostate cancer, kidney cancer, bladder cancer, enlarged prostate, and more. Check back for the latest news from AUA 2017. 

BOSTON—Selective targeted biopsy of PI-RADS 4 and 5 prostate lesions improves detection of clinically significant tumors among prostate cancer patienton active surveillance (AS) undergoing confirmatory biopsy, researchers reported at the American Urological Association 2017 annual meeting.

In a study of 356 AS patients, Zachary Hamilton, MD, and colleagues at the University of California San Diego compared with magnetic resonance imaging (MRI)-fusion guided targeted biopsy (TB) to standard ultrasound-guided systematic biopsy (SB). The MRI-fusion biopsy group underwent a standard 12-core systematic biopsy with an additional 2 to 3 cores of the targeted lesion. The primary outcome was upgrading, defined as detection of Gleason sum 3+4=7 cancer or higher.

Of the 356 patients, 195 (58%) underwent prostate MRI after the initial diagnostic biopsy. Of these, 138 (71%) had MRI-detectable lesions. After implantation of TB in May 2014, 42 AS patients underwent confirmatory MRI-fusion TB: 9 (21.4%), 19 (45.2%), 7 (16.7%) and 7 (16.7%) with PI-RADS 2, 3, 4, and 5 lesions, respectively. Stratification by PI-RADS revealed Gleason sum of 3+4=7 or higher diagnosis in 0 (0%), 4(21%), 6(86%), and 6 (86%) of PI-RADS 2, 3, 4, and 5 lesions, respectively.

Compared with SB, TB of PI-RADS 4 and 5 lesions detected 58% more Gleason 3+4=7 or higher cancers (86% vs 28%), and was associated with increased odds of upgrading in multivariable analysis. The positive predictive value of PI-RADS 4 and 5 lesions for Gleason 3+4=7 or higher cancer was 86%, according to the researchers.

“In the United States, the vast majority of men with low-risk prostate cancer are being counseled regarding active surveillance protocols,” Dr Hamilton told Renal & Urology News. “So we're looking for ways to enhance those protocols to determine who best fits into it and who is at risk for upstaging. And MRI is becoming a big part of that. In our study, using MRI for patients on active surveillance, we were able to detect that those who had MRI PI-RADS 4 and 5 lesions had a significant risk of upstaging at repeat biopsy, and that those patients who were upstaged had a higher chance of changing to a definitive treatment, whether that be radiation or surgery. So use of MRI biopsy for patients on active surveillance can impact their clinical care decision.”

Visit Renal and Urology News' conference section for continuous coverage from AUA 2017.

Reference

Hamilton Z, Nseyo U, Cotta B, et al. Clinical  utility of MRI/fusion biopsy in prostate cancer patients on active surveillance. [abstract] J Urol 2017;197(4S):e556. Poster presented at the American Urological Association 2017 annual meeting in Boston on May 13, 2017. Poster MP43-07.

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