Magnetic resonance imaging (MRI) is better than systematic biopsies for diagnosing prostate cancer; thereby reducing redundant biopsies, a Cochrane review and meta-analysis revealed. However, the findings are practice-changing, coauthor Dr. Ivo Schoots of Erasmus University Medical Center Rotterdam told Reuters Health by email.
“Therfore recommending upfront MRI in all men suspected to have prostate cancer is justified,” he added, “based on 1) the potential reduction of biopsies of approximately one-third of tested men whose prostate MRI does not show any suspicious regions; 2) the lower detection rates of insignificant prostate cancer by the MRI pathway in comparison to systematic biopsy; and 3) at least an equal detection of clinically important prostate cancers by the MRI pathway and systematic biopsy.”
Significant prostate cancer
“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,” he said. But for the review, published by The Cochrane Library in April and in European Urology; Dr. Schoots and colleagues searched the literature for studies that investigated one or more index tests verified by the reference standard (template-guided biopsy) and paired testing of the MRI pathway with systemic biopsy.
However, ultimately, 43 studies included. However, using a baseline cancer prevalence of 30%; so the MRI pathway (sensitivity 0.72; specificity 0.96; based on eight studies) may result in 216 true positives; 28 false positives, 672 true negatives, and 84 false negatives per 1,000 men, the team found. By contrast, systematic biopsy (sensitivity 0.63; specificity 1.00; four studies) may result in 189 true positives, 0 false positives, 700 true negatives; also 111 false negatives per 1,000 men.
However, comparisons of the MRI pathway with systematic biopsy for significant disease; yielded pooled detection ratios of 1.05 (20 studies) in biopsy-naive men and 1.44 (10 studies) in men with a prior negative biopsy. But, detection ratios were 0.63 and 0.62, respectively, for insignificant disease.
Dr. Schoots said, “But for MRI-directed pathways to deliver the intended benefits; the quality of the entire diagnostic process must be ensured by having robustly trained technologists, experienced radiologists; and (experienced) practitioners conducting MRI-directed biopsy. Therefore, quality control and quality assurance procedures must be integrated into diagnostic work‐ups.”
“Hence for those patients not undergoing systematic biopsy after negative MRI scans; a robust safety net of PSA and imaging monitoring must be in place, as per local clinical practice and consistent with clinical goals for individual patients, with roles and responsibilities defined by multidisciplinary management teams,” he stressed.
Dr. Alexander Kutikov, Chief, Division of Urology and Urologic Oncology at Fox Chase Cancer Center in Philadelphia said he “absolutely” agrees with the study findings and uses the MRI approach in his practice. “However, these data yet again underscore the deliverables of a high-quality multiparametric MRI (mpMRI) of the prostate: 1) Significant number of patients are able to avoid prostate biopsy and 2) those who require biopsy are able to receive one that is much more accurate by targeting the lesions seen on MRI,” he told Reuters Health by email.
Patients can be diagnosed
“Concerns about costs must account for the fact that some patients are able to avoid a biopsy; and its complications, and the fact that some patients can be diagnosed with an aggressive prostate cancer; in a more timely fashion via ultrasound/MRI fusion techniques that harnesses the MRI imaging,” he said.
“But the main challenge is the fact that quality of mpMRI and its interpretation vary widely,” he noted. “But a quality fusion biopsy program requires close cooperation between radiologists; and urologists to assure high fidelity imaging, interpretation, and fusion targeting.”
“However, insurers have been extremely slow to respond to these data,” he added. “Obtaining an mpMRI historically has been extremely challenging with (some payers). In my opinion, patients receive a lower level of care when a high quality mpMRI; is denied by these payers.”