Originally published 5/25/2016
We are happy to report that an extensive body of literature on multiparametric MRI (mpMRI) of the prostate has mushroomed since the 2014 article[i] cited in the original blog below. During the intervening years, more attention has been paid to mpMRI’s ability to distinguish between clinically insignificant prostate cancer (CISPCa) vs. clinically significant prostate cancer (CSPCa). This is crucial, since it helps avoid overtreatment of insignificant disease, and tailored treatment planning for significant disease that can become deadly.
For purposes of updating the earlier blog, we chose a review article published online in August, 2021 by Haider, et al.[ii] They selected 36 published randomized, controlled trials (RCTs) of accurate detection and diagnosis of mpMRI and MRI-guided biopsy. In all studies, patients were enrolled due to elevated risk for CSPCa, though some had not yet been biopsied, while others had a previous negative TRUS-guided biopsy. The authors found the range of sensitivities and specificities as follows:
|No previous biopsy||Previous negative TRUS biopsy|
|Sensitivity for CSPCa (range)||87-96%||78-100%|
|Specificity for CSPCa (range)||29-45%||30-100%|
As for biopsy comparison, increased detection and diagnosis favored MRI-guided targeted biopsy over systematic TRUS biopsy. The authors concluded, “The growing acceptance of MPMRI utilisation internationally and the recent publication of several RCTs regarding MPMRI in reducing CISPCa detection rates, particularly in biopsy-naïve men, without loss of sensitivity for CSPCa necessitates the synthesis of updated evidence examining MPMRI in the diagnosis of CSPCa.” In other words, mpMRI rules out the need for treating insignificant disease while maintaining high accuracy in detecting significant disease.
There is a saying that a single tree does not make a forest. In the same way, a single published clinical study does not make a scientific proof. In fact, good scientists must be skeptics of their own results, asking hard questions and holding the results up to high standards. One of those standards concerns repeatability—if a second study, or the same study design done by someone else doesn’t produce the same results, it’s a problem.
One type of research involves searching through published studies exploring the same phenomenon. This is called a review or survey of the literature. A researcher who embarks on this type of study needs a library, not a laboratory, but the study design criteria and statistical analysis must still meet high research standards. If their scientific peers agree that this is the case, their article merits publication as much as clinical research with patients does, because it pools and compares data from numerous other researchers exploring the same thing. Were the results repeatable across several studies? If so, skepticism relaxes and acceptance grows.
A group of researchers from Radboud University Nijmegen Medical Center in The Netherlands has long been involved in publishing their own data on multiparametric MRI of the prostate. Their own work provides evidence that mpMRI offers great promise for various applications: detecting and diagnosing prostate cancer, monitoring during active surveillance, confirming treatment effectiveness, etc. But, like all good scientists, they ask if the work of others bears out their results. Are they repeatable?
They conducted a review and analysis of the diagnostic accuracy of T2-weighted MRI combined with two functional parameters: diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI (DCE-MRI). The searched electronic databases of published articles up to February 3, 2012. The articles they chose to include in their analysis were diagnostic accuracy studies using T2-weighted MRI, DWI and DEC-MRI to detect prostate cancer AND actual tissue samples (either biopsy or prostatectomy) from the same patients as a reference standard for imaging accuracy. Two independent reviewers evaluated the methodologic quality of each study, and seven papers ultimately met their inclusion criterion. The seven studies represented a total of 526 patients, which is a sizable population for assessing how accurate the imaging was compared to the tissue sample analysis (called histopathology). The team then performed statistical calculations on the assembled data. The results for MRI prostate cancer detection are shown in this table:
MRI specificity (correctly identified presence of significant disease) 88%
MRI sensitivity (correctly identified lack of significant disease) 74%
Negative predictive value Range from 0.65 – 0.94 (probability that those who did not have significant disease truly did not have it)
The authors concluded that the high NPVs and sensitivities imply a potential role for mpMRI in detecting prostate cancer. In other words, the consistent (repeatable) performance of mpMRI is more trustworthy when it is reported in numerous peer-reviewed published studies.
NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.
[i] de Rooij M, Hamoen EH, Fütterer JJ, Barentsz JO, Rovers MM. Accuracy of multiparametric MRI for prostate cancer detection: a meta-analysis. AJR Am J Roentgenol. 2014 Feb;202(2):343-51.
[ii] Haider MA, Brown J, Yao X, Chin J, Perlis N, Schieda N, Loblaw A. Multiparametric Magnetic Resonance Imaging in the Diagnosis of Clinically Significant Prostate Cancer: an Updated Systematic Review. Clin Oncol (R Coll Radiol). 2021 Dec;33(12):e599-e612.