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Home » EU Health, Health, Prostate Cancer

The role of MRI in prostate cancer expands

Submitted by on 30 Mar 2016 – 15:25

The role of imaging techniques such as multiparametric MRI (mpMRI) in prostate cancer is set to expand in the coming years, particularly in cases where technology is more integrated with treatment. Prof Jelle Barentsz, Professor of Radiology, Radboud ProstateMR-Reference Center discusses the details

barentzThe main disadvantages of the current diagnostic pathway in men with an elevated risk of prostate cancer (PCa) are that: (a) systematic transrectal ultrasound (TRUS) prostate biopsy (PB) misses a substantial proportion (20%) of significant PCa because of inherent systematic sampling errors, especially in the anterior prostate [1,2]; (b) misclassifies pathologic status including Gleason score (GS) and tumour stage [3]; and (c) detects a high proportion of men with disease that is unlikely to be harmful (clinically insignificant), with subsequently overtreatments resulting in unintended harm [4]. The latter was the main reason for the U.S. Preventive Services Task Force recommendation against prostate-specific antigen- based screening for prostate cancer in 2012 [5].

Can multi-parametric MRI solve these problems?

There is increasing evidence, such as two Level 1a systematic reviews [6,7], a Level 1a prospective clinical randomised trial [8], and multiple Level 1b studies [9,10], that multi-parametric magnetic resonance imaging (mpMRI) is the best method of visualising primary significant PCa. It is, therefore, widely accepted that mpMRI has the performance characteristics to help manage men with suspected or proven PCa [11,12]. The clinical utility in terms of the ability to ‘‘rule in’’ and ‘‘rule out’’ the presence of significant disease depends on using the mpMRI approach, image quality, reading system, and reporter expertise [13–16]. The cancer detection ability of mpMRI is dependent on the anatomic location, tumour volume, and aggressiveness (GS) of the underlying cancer [3]. mpMRI detected lesions are not always significant malignant lesions [17]; false positive cancer/non-cancer cases do occur, thus adequate biopsy sampling is mandated for each lesion detected [18].

What type of cancers does mpMRI-TB detect?

Literature indicates an improved ability of mpMRI-PB is to detect clinically significant cancers. A recent systematic review showed that the detection rate of clinical significant cancer is higher (44–87%) than the rates reported for TRUS-PB [7], depending on the definition of clinical significance used for targeted biopsy; this ability applies equally to biopsy naıve and men with prior negative biopsies. Histologic grades on mpMRI-TB show high concordance (88%) with final pathology after prostatectomy, which is a sharp contrast to TRUS-PB (55% concordance rate) [3].

Does mpMRI-PB systematic miss clinically significant disease?

The key questions are: (1) what proportion of men with negative mpMRI harbour cancers that would require radical therapy if detected; and (2) what proportion of patients with significant disease would be detected by an additional backup TRUS-PB? The reported negative predictive value (NPV) of mpMRI-PB for significant disease has been reported to be high: 63-98% [7]. The central issue is the balance between benefits and limitations of mpMRI- targeted biopsy (TB) when used alone compared with the strategy of combined mpMRI-TB with backup TRUS-PB in men with positive mpMRI findings. This was recently addressed in a very large prospective trial [9]. In 1003 men, there were additional cancers detected when mpMRI-TB was combined with TRUS-PB. However, of the 103 additional cancers detected, the majority were low risk (83% low risk; 5% high risk). Importantly, 200 combined biopsies yielded only one additional high-risk cancer, but over-diagnosed 17 low risk cancers. Also, there was no change in risk stratification in the majority of patients (857 patients; 85%), with only 19 men (2%) converting from no-cancer or low risk disease to intermediate or high risk with the combined approach. Taken together, these and other data strongly argue against the strategy of combining mpMRI-PB with systematic TRUS-TB in order to improve biopsy yields.

Is there a performance difference of mpMRI-TB in biopsy naive patients compared with those with previous negative TRUS-PB?

In previous negative biopsy patients, mpMRI-PB greatly increased detection rates (+54%) of significant cancers and markedly reduced (-49% and -18% respectively) insignificant cancers detection, rendering the mpMRI-TB approach clinically effective. Thus both the European Association of Urology 2015 and the UK National Institute of Clinical and Care Excellence 2014 guidelines recommend mpMRI before repeat TRUS biopsy. UK National Institute of Clinical and Care Excellence 2014 additionally recommends against a second biopsy if mpMRI is negative, unless high-risk features are present [11].

Challenges

To enhance interdisciplinary communications between radiologists and referring clinicians, it is essential that uniform, understandable terminology and content of radiology reports be used. Reports should include assessment categories of suspicion for clinically significant disease to facilitate the use of targeted biopsy. The Prostate Imaging Reporting and Data System (PI-RADS) of the European Society of Urogenital Radiology (ESUR) has been widely accepted and validated [19]. A new PI-RADS version 2 was recently adopted by the AmericanCollege of Radiology and ESUR, but has yet to be validated [20,21]. To incorporate mpMRI findings using the PI-RADS system with biopsy strategies new pathways should be developed [22].

Training and quality controls

Furthermore, to achieve and maintain good mpMRI diagnostic performance, adequate training, supervision, and quality-control of the acquisition of the images, the PI-RADS assessment, and the targeted biopsy procedure are needed. This is particularly true when complex image registration procedures are needed to enable small lesions to be sampled. Importantly, histology feedback is required with continuous audit checks within the multi disciplinary care teams. An important consideration for these teams is, what to do when a negative biopsy is obtained from a highly suspicious region on imaging.

Extensive training programs by Specialised Prostate MRI Centres must be developed in order to fulfil the rapidly increasing demand of mpMRI. These Specialised Centres will train and certify multiple Diagnostic Centres of Excellence throughout Europe, where diagnosis of prostate cancer is optimized. To ensure continuous high quality, the training and certification should be followed by a quality control program. In this way, a European prostate diagnostic network of Specialised Prostate MRI Centres (for training and QC) and Diagnostic Centres of Excellence (to provide best quality care) will be created. The potential advantages of such a prostate network are: a) better quality through double reading and inter-collegial consultation, b) faster implementation of newly validated techniques, c) will allow sharing knowledge, and d) create large scientific databases to speed up the validation process. For double reading of prostate mpMRI already tools are available and in some places implemented, being internet connected PI-RADS workstations.

Costs

The upfront cost per cancer diagnosed is greater using mpMRI-PB methods, in part because of the need for capacity building and tooling up. This may be counterbalanced by changes in the risk stratification of diagnosed patients towards those requiring radical treatments. Modelling studies in the Netherlands and the United Kingdom suggested that an mpMRI-PB strategy can be cost-effective while maintaining the benefits of reduced overdiagnosis and overtreatment together, with improvements in quality of life [23,24]. To get health service provider buy-in, the therapeutic consequences of mpMRI-PB also need to be considered [25].

Conclusions

mpMRI-PB changes the risk stratification of men diagnosed with prostate cancer towards improved detection of men with cancers requiring radical treatments. To realise the clinical benefits of mpMRI-PB without overwhelming current resources, appropriate patient selection and investments in diagnostic and communication tools are needed. Imaging interpretation should be aligned with clinical management plans. Effective communication of imaging findings and improved urologic understanding of imaging uncertainties will improve the outcomes for men with suspected prostate cancer.

To meet the increasing demand of mpMRI a prostate network of Specialised Prostate MR Centers for training and QC, and Diagnostic Centers of Excellence to provide optimal care should be established as soon as possible

* This paper is based on Barentsz et al [26] and Padhani et al [22].

References: 

[1] Djavan B, Ravery V, Zlott A, et al. Prospective evaluation of prostate cancer detected on biopsies 1, 2, 3 and 4: when should we stop? J Urol 2001;166:1679–83.

[2] Guichard G, Larre´ S, Gallina A, et al. Extended 21-sample needle biopsy protocol for diagnosis of prostate cancer in 1000 consecutive patients. Eur Urol 2007;52:430–5.

[3] Hambrock T, Hoeks C, Hulsbergen-van de Kaa C, et al. Prospective assessment of prostate cancer aggressiveness using 3-T diffusion-weighted magnetic resonance imaging-guided biopsies versus a systematic 10-core transrectal ultrasound prostate biopsy cohort. Eur Urol 2012;61:177–84.

[4] Bul M, van den Bergh RC, Zhu X, et al. Outcomes of initially expec- tantly manged patients with low or intermediate risk screen- detected localized prostate cancer. BJU Int 2012;110:1672–7.

[5] Moyer V. Screening for prostate cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2012;157: 120–34.

[6] Schoots IG, Roobol MJ, Nieboer D, et al. Magnetic resonance imaging– targeted biopsy may enhance the diagnostic accuracy of significant prostate cancer detection compared to standard transrectal ultra- sound-guided biopsy: A systematic review and meta-analysis. Eur Urol 2015. http://dx.doi.org/10.1016/j.eururo.2014.11.037

[7] Futterer JJ, Briganti A, De Visschere P, et al. Can clinically significant prostate cancer be detected with multiparametric magnetic reso-nance imaging?. A systematic review of the literature. Eur Urol 2015. http://dx.doi.org/10.1016/j.eururo.2015.01.013

[8] Panebianco V, Barchetti F, Sciarra A, et al. Multiparametric MRI vs. standard care in men being evaluated for prostate cancer: A ran-domised study. Urol Oncol 2015;33, 17.e1–7.

[9] Siddiqui MM, Rais-Bahrami S, Baris Turkbey B, et al. Comparison of MR/Ultrasound Fusion–Guided Biopsy With Ultrasound-Guided Biopsy for the Diagnosis of Prostate Cancer. JAMA 2015;313: 390–7.

[10] Pokorny MR, de Rooij M, Duncan E, et al. Prospective study of diagnostic accuracy comparing prostate cancer detection by trans-rectal ultrasound-guided biopsy versus magnetic resonance (MR) imaging with subsequent MR-guided biopsy in men without pre-vious prostate biopsies. Eur Urol 2014;66:22–9.

[11] National Institute for Health and Care Excellence 2014 recom- mendations. http://www.nice.org.uk/guidance/cg175/chapter/ 1-recommendations

[12] European Association of Urology 2015 Guidelines for prostate cancer. http://uroweb.org/wp-content/uploads/09-Prostate-Cancer_ LR.pdf

[13] Vache T, Bratan F, Mege-Lechevallier F, et al. Characterization of prostate lesions as benign or malignant at multiparametric MR imaging: comparison of three scoring systems in patients treated with radical prostatectomy. Radiology 2014;272:446–55.

[14] Gaziev G, Wadhwa K, Barret T, et al. Defining the learning curve for mutliparametric MRI of the prostate using MRI-TRUS fusion-guided transperineal prostate biopsies as a validation tool. BJU Int 2015. http://dx.doi.org/10.1111/bju.12892,

[15] Muller BG, Shih JH, Sankineni S, et al. Prostate cancer: interobserver agreement and accuracy with the revised prostate imaging report-ing and data system at mp MRI. Radiology 2015. http://dx.doi.org/ 10.1148/radiol.2015142818, In press.

[16] De Rooij M, Hamoen EHJ, Futterer JJ, et al. AJR. Accuracy of multi-parametric MRI for prostate cancer detection: a Meta-Analysis. AJR 2014;202:343–51.

[17] Bour L, Schull A, DelongchampsNB, et al. Multiparametric MRI. features of granulomatous prostatitis and tubercular prostate ab-scess. Diagn Interv Imaging 2013;94:84–90.

[18] Willis SR, Ahmed HU, Moore CM, et al. Multiparametric MRI followed by targeted prostate biopsy for men with suspected prostate cancer: a clinical decision analysis. BMJ Open 2015. http://dx.doi.org/10.1136/bmjopen-2014-004895, In press.

[19] Barentsz JO, Richenberg J, Clements R, et al. ESUR prostate MR guidelines 2012. Eur Radiol 2012;22:746–57.

[21] Barentsz JO, Weinreb, Verma S, et al. Synopsis of the PI-RADS v2 Guidelines for Multiparametric Prostate Magnetic Resonance Imaging and Recommendations for Use. European Urology 2016;69:41-9.

[22] Weinreb J, Barentsz JO, Choyke PL. PI-RADS Prostate Imaging- Reporting and Data System: 2015 version 2. European Urology 2016;69:16-40.

[22] Padhani AW, Petralia G, Sanguedolce F. Magnetic Resonance Imaging Before Prostate Biopsy: Time to Talk. European Urology 2016;69:1-3.

[23] De Rooij M, Crienen SJ, Witjes JA, et al. Cost-effectiveness of magnetic resonance (MR) imaging and MR-guided targeted biopsy versus systematic transrectal ultrasound–guided biopsy in diag-nosing prostate cancer: A modelling study from a health care perspective. Eur Urol 2014;66:430–6.

[24] Mowatt G, Scotland G, Boachie C, et al. The diagnostic accuracy and cost-effectiveness of magnetic resonance spectroscopy and enhanced magnetic resonance imaging techniques in aiding the localisation of prostate abnormalities for biopsy: a systematic review and economic evaluation. Health Technol Assess 2013; 17:vii–xix, 1–281.

[25] Willis SR, Ahmed HU, Moore CM, et al. Multiparametric MRI followed by targeted prostate biopsy for men with suspected prostate cancer: a clinical decision analysis. BMJ Open 2014;4: e004895.

[26] Barentsz JO, Futterer JJ, Padhani AR. Will MRI-guided biopsy replace sytematic biops? European Urology Focus 2015;1:152-155.