Review: MRI pathway most accurate strategy for detecting clinically significant PCa

August 13, 2019

The magnetic resonance imaging pathway is the most accurate diagnostic strategy for detecting clinically significant prostate cancer, according to a recent literature review.

The magnetic resonance imaging (MRI) pathway is the most accurate diagnostic strategy for detecting clinically significant prostate cancer, according to a recent literature review.

Researchers in the Netherlands examined the literature up to July 2018, including 43 studies and a total of 13,805 men at prostate cancer risk. They compared MRI only, MRI-targeted biopsy, MRI pathway (MRI with or without MRI-targeted biopsy), and systematic biopsy to template-guided biopsy as a reference standard. The study was published in the Cochrane Database of Systematic Reviews (2019 Apr 25; 4:CD012663).

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Recommending upfront MRI in all men suspected to have prostate cancer is justified, according to review author I.G. Schoots, MD, PhD, of Erasmus University Medical Center Rotterdam, the Netherlands. He and his coauthors base this on these findings:

  • MRIs that don’t show any suspicious regions reduce the need for biopsies by about one third on tested men.

  • Compared to systematic biopsy, MRI pathway has lower detection rates of insignificant prostate cancer.

  • MRI pathway and systematic biopsy are at least equally accurate for detecting clinically important prostate cancers.

“The attraction to health systems and to patients of omitting systematic biopsy, with its attendant morbidities, is clear,” according to Dr. Schoots. “However, MRI is ‘waterproof’ but not ‘watertight,’ and where there is a high probability of clinically significant prostate cancer, systematic biopsies should remain a very real option even in men with negative MRI scans.”

The review suggests that prostate MRI and MRI-directed biopsy is an evidence-based first strategy and in a significant minority of patients the only test that they will need, with the option of systematic biopsy depending on a patient’s risk, he said.

The approach has taken hold in countries other than the U.S. In the Netherlands, the work-up of men with suspected prostate cancer includes the upfront MRI. Use of MRI early on in these patients is also common practice in the United Kingdom, and the European Association of Urology changed its Prostate Cancer Guidelines in March 2019 to recommend performing multiparametric (mp) MRI before prostate biopsy in biopsy-naïve patients and those with a prior negative biopsy.

Next -Dr. Schoots: Paradigm is changingU.S. urologists have not yet accepted MRI as a first-line diagnostic strategy in suspected prostate cancer. But Dr. Schoots says he and his colleagues are convinced the paradigm is changing towards MRI-directed diagnostic pathways for all men in the U.S. and elsewhere.

Data comparing MRI to template-guided biopsy shows MRI performs well diagnostically, with high sensitivity at 0.91, to rule out clinically significant prostate cancer.

Research looking at the MRI pathway compared to template-guided biopsy shows the diagnostic performance of the MRI pathway-combining MRI with MRI-targeted biopsies-is lower than of MRI alone, as the sensitivity is 0.72, according to Dr. Schoots.

“A contributing factor could be that targeting biopsy procedures miss the identified and suspected lesion on MRI,” he said.

The diagnostic performance of the generally practiced systematic biopsy is lower, at 0.63, than the MRI pathway.

“The ‘agreement analysis’ between both diagnostic tests, the MRI-pathway and systematic biopsy in biopsy-naive men, showed that the MRI pathway has favorable diagnostic accuracy over systematic biopsy in clinically significant prostate cancer detection. Compared to systematic biopsy, it increases the number of significant cancers detected while reducing the number of insignificant cancers diagnosed and biopsies performed,” Dr. Schoots said.

It’s important that U.S. urologists consider the practicalities of the approach as MRI-directed diagnostic pathways become more common. The results of published studies-many done in high-volume expert centers with state-of-the-art equipment, optimized protocols, and high experienced subspecialized radiologists-might not be applicable to general clinical practice, according to Dr. Schoots.

“For MRI-directed pathways to deliver the intended pathway benefits, the quality of the entire diagnostic process must be ensured by having robustly trained technologists, experienced radiologists, and practitioners who conduct MRI-directed biopsy,” he said. “Therefore, quality control and quality assurance procedures must be integrated in diagnostic work-ups.”

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Local clinical urology practices, for example, should have a robust safety net of PSA and imaging monitoring in place for patients with negative MRI scans who are not undergoing systematic biopsy. The care should be in line with the patient’s individual clinical goals and include a multidisciplinary management team with well-defined roles and responsibilities.

Dr. Schoots was among the authors of a recent paper that noted the diagnostic chain of the MRI-directed diagnostic pathway is “as strong as its weakest link” (Eur Urol 2019; 75:889-90).

“Monitoring performance measures of each link in the MRI-directed diagnostic chain needs to be developed, monitored continuously, and critically appraised to ensure quality care,” he said.

Today’s literature falls short of providing clear guidance on which patients may benefit most from MRI, according to Dr. Schoots. Some, as a result, are turning their attention towards using MRI preselection tests, including blood and urine tests. In appropriately chosen patients, multivariate risk prediction tools that include MRI results can support physicians and patients in biopsy decision-making. But more research is needed on the added value of risk prediction models that incorporate MRI information, he said.