TOPLINE:

In a cohort of US veterans with prostate cancer who were on active surveillance, negative multiparametric MRI had a 75% negative predictive value for ruling out disease of grade group 2 or higher at confirmatory biopsy and a corresponding value of 77% at surveillance biopsy, indicating that MRI alone missed a substantial portion of clinically significant cancers.

METHODOLOGY:

• Active surveillance for favorable‑risk prostate cancer commonly includes a confirmatory biopsy to detect under-sampled disease of a higher grade. Recent guidelines have proposed that multiparametric MRI might replace confirmatory biopsy, but data supporting its accuracy are limited.
• Researchers analyzed data from 1901 US veterans diagnosed with grade group 1 or 2 prostate cancer between 2013 and 2023 who underwent MRI within 180 days prior to confirmatory and/or surveillance biopsy. They extracted clinical variables from the MRI and biopsy reports using natural language processing.
• The primary outcome was prostate cancer of grade group 2 or higher on confirmatory or surveillance biopsy. A Prostate Imaging-Reporting and Data System (PI-RADS) score of 3 or higher on MRI was considered positive.

TAKEAWAY:

• MRI showed negative predictive values of 75% at confirmatory biopsy and 77% at surveillance biopsy for detecting prostate cancer of grade group 2 or higher, indicating that MRI alone missed about one quarter of clinically significant cancers.
• For patients with grade group 1 prostate cancer at diagnostic biopsy, the negative predictive value increased to 79% at both confirmatory and surveillance biopsies, whereas for those with grade group 2 prostate cancer at diagnostic biopsy, the negative predictive value was substantially lower.
• Patients with a prostate-specific antigen density below 0.15 ng/mL² had higher negative predictive values (confirmatory biopsy, 78%; surveillance biopsy, 83%); overall, negative predictive values were lower for Black patients than those for White patients.
• MRI demonstrated better performance in ruling out prostate cancer of grade group 3 or higher, with negative predictive values exceeding 95% across multiple subgroups when PI-RADS scores of 3-5 were considered positive.

IN PRACTICE:

“While quality multiparametric MRI clearly can help guide prostate biopsies and improve diagnosis, our data confirm that relying on MRI as a surrogate for biopsy in AS [active surveillance] would result in underdiagnosis of clinically significant cancers — though we acknowledge few of these would likely be imminently life-threatening,” the study authors wrote. They noted that improvements over PI-RADS scores are in the pipeline — but until then, “routine confirmatory testing for active surveillance should still include biopsy.”

SOURCE:

The study, led by Matthew Cooperberg, MD, MPH, of the San Francisco Veterans Affairs Medical Center in San Francisco, was published online in JAMA Oncology.

LIMITATIONS:

MRI and biopsy decisions were made through routine clinical decision-making, potentially leading to selection bias as patients with negative MRI results may not have received a biopsy. Additionally, the researchers could not account for MRI quality or inter-reader variability in PI-RADS assignment.

DISCLOSURES:

The study was supported by the VA Office of Research Development, Cooperative Studies Program. Several authors reported receiving grants or personal fees and having other ties with various sources. Full disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.