Platinum Priority – Prostate CancerEditorial by Axel Heidenreich on pp. 495–497 of this issueMagnetic Resonance Imaging for the Detection, Localisation, and Characterisation of Prostate Cancer: Recommendations from a European Consensus Meeting
Introduction
Magnetic resonance imaging (MRI) has considerable potential to improve the prostate cancer diagnostic pathway. Until fairly recently, the accuracy of morphologic MRI to detect, localise, and characterise prostate cancers was limited, and as a result, MRI has not been routinely incorporated into clinical care. However, evidence is accumulating that suggests an improved performance of MRI, provided that modern sequences are used and their outputs combined in so-called multiparametric MRI (mpMRI). Currently these include T1- and T2-weighted images, dynamic contrast, diffusion weighting, and proton spectroscopy [1], [2].
Although experts in the field generally regard the performance characteristics of mpMRI of the prostate as promising [3], there exists professional disagreement on its accuracy and usefulness in clinical practice [4], limiting wider adoption. These concerns relate in part to the variable quality and methodology of studies that have resulted in marked variation in indication, conduct, interpretation, and reporting [5], [6], [7], [8], [9], [10], [11]. These issues have made it difficult to summarise the literature in any meaningful way [1].
This problem is not a new one. Over the last 2 decades, breast cancer experts have had to manage similar issues in relation to x-ray mammography and, more recently, breast MRI [12], [13]. The solution to this problem was formal attempts to establish agreement among experts on areas of uncertainty. As a result, a series of recommendations emerged on the minimum standards acceptable for mammography [14], [15], [16], [17] and breast MRI [18], [19]. The principal innovation proved to be the incorporation of scoring systems to communicate the likelihood of malignancy in women with suspected breast cancer. These recommendations conferred at least two benefits: reduced interobserver variability [20], [21] and improved positive predictive value for obtaining pathology from breast biopsy [21].
Based on the breast cancer experience, it seemed timely and necessary to see if experts in the field of prostate cancer and prostate MRI could achieve similar consensus. This paper reports the recommendations of a panel of uroradiology experts who participated in a formal consensus process aimed at defining when prostate MRI should be applied and how it should be conducted and reported.
Section snippets
The consensus method
A number of formal consensus methods have been used in health care settings [22], [23]. The RAND-UCLA Appropriateness Method (RAM) was chosen as the most appropriate for our objectives [24]. RAM includes a combination of postal and face-to-face consensus rounds. It is most suited to topic areas where there is little or poor quality evidence to enable a gold standard recommendation. Appropriateness levels are used to communicate the perceived balance between risks and benefits of each item under
Results
The premeeting questionnaire included 537 items, reduced to 520 items during the meeting. Nineteen items were added and 36 items omitted. Wording changes were made to 20 items.
Summary of results
The use of the RAM method produced consensus in 61% of the items (315 of 520). Consensus was achieved in several key areas where inconsistency between studies had previously been a problem. In particular, the panel recommended that all sequences (T2-weighted, diffusion-weighted, and dynamic contrast enhanced sequences) except proton spectroscopy should comprise the minimum standard. Recent evidence from a large prospective multicentre study showing no benefit of spectroscopy for prostate cancer
Conclusions
MpMRI is undergoing a period of development with a number of reports demonstrating its potential as a tool in the diagnostic pathway for prostate cancer. Consistency in conduct and reporting is required before more widespread dissemination of this imaging modality. Through formal consensus methods, we have agreed on a number of standards required for imaging and reporting mpMRI of the prostate. Before these recommendations can be developed into protocols, they must be validated in prospective
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