Skip to main content

Main menu

  • Home
  • Content
    • Current issue
    • Past issues
    • Early releases
    • Collections
    • Sections
    • Blog
    • Infographics & illustrations
    • Podcasts
    • COVID-19 articles
    • Obituary notices
  • Authors & Reviewers
    • Overview for authors
    • Submission guidelines
    • Submit a manuscript
    • Forms
    • Editorial process
    • Editorial policies
    • Peer review process
    • Publication fees
    • Reprint requests
    • Open access
    • Patient engagement
  • Physicians & Subscribers
    • Benefits for Canadian physicians
    • CPD Credits for CMA Members
    • Subscribe to CMAJ Print
    • Subscription prices
    • Obituary notices
  • Alerts
    • Email alerts
    • RSS
  • JAMC
    • À propos
    • Numéro en cours
    • Archives
    • Sections
    • Abonnement
    • Alertes
    • Trousse média 2023
    • Avis de décès
  • CMAJ JOURNALS
    • CMAJ Open
    • CJS
    • JAMC
    • JPN

User menu

Search

  • Advanced search
CMAJ
  • CMAJ JOURNALS
    • CMAJ Open
    • CJS
    • JAMC
    • JPN
CMAJ

Advanced Search

  • Home
  • Content
    • Current issue
    • Past issues
    • Early releases
    • Collections
    • Sections
    • Blog
    • Infographics & illustrations
    • Podcasts
    • COVID-19 articles
    • Obituary notices
  • Authors & Reviewers
    • Overview for authors
    • Submission guidelines
    • Submit a manuscript
    • Forms
    • Editorial process
    • Editorial policies
    • Peer review process
    • Publication fees
    • Reprint requests
    • Open access
    • Patient engagement
  • Physicians & Subscribers
    • Benefits for Canadian physicians
    • CPD Credits for CMA Members
    • Subscribe to CMAJ Print
    • Subscription prices
    • Obituary notices
  • Alerts
    • Email alerts
    • RSS
  • JAMC
    • À propos
    • Numéro en cours
    • Archives
    • Sections
    • Abonnement
    • Alertes
    • Trousse média 2023
    • Avis de décès
  • Visit CMAJ on Facebook
  • Follow CMAJ on Twitter
  • Follow CMAJ on Pinterest
  • Follow CMAJ on Youtube
  • Follow CMAJ on Instagram
Commentary

Magnetic resonance imaging diagnosis of prostate cancer: promise and caution

Douglas C. Cheung and Antonio Finelli
CMAJ October 28, 2019 191 (43) E1177-E1178; DOI: https://doi.org/10.1503/cmaj.190568
Douglas C. Cheung
Division of Urology (Cheung), Department of Surgery and Surgeon Scientist Training Program (Cheung), University of Toronto; Division of Urology (Finelli), Department of Surgery, University Health Network, Toronto, Ont.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Antonio Finelli
Division of Urology (Cheung), Department of Surgery and Surgeon Scientist Training Program (Cheung), University of Toronto; Division of Urology (Finelli), Department of Surgery, University Health Network, Toronto, Ont.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Tables
  • Related Content
  • Responses
  • Metrics
  • PDF
Loading
KEY POINTS
  • Randomized controlled trial evidence supports the introduction of magnetic resonance imaging (MRI) for biopsy-naive men with suspected prostate cancer to improve detection of clinically important cancer, decrease the overdiagnosis and treatment of clinically unimportant cancer, and avoid biopsy for men at low risk.

  • However, poor interobserver reliability and reproducibility, unknown long-term follow-up and natural history of MRI-detected lesions, and current capacity limitations in the Canadian context suggest that caution is warranted in implementing services.

  • Implementation would be challenging within the universally funded Canadian health care system; initially, rollout at high-volume cancer centres would be prudent to ensure appropriate patient selection, image interpretation and accuracy of targeted biopsy, while a robust knowledge translation strategy for primary care and specialist physicians would minimize confusion.

Among solid-organ tumours, prostate cancer is alone in being diagnosed via a nontargeted biopsy approach. Systematic transrectal ultrasonography-guided biopsy has been the standard of care to detect clinically important prostate cancer since 1989.1 Yet modern image acquisition and quantification with magnetic resonance imaging (MRI) has recently been shown to delineate prostatic disease accurately, reproducibly and noninvasively.2,3 Is it now time to proceed to widespread use of MRI to diagnose and stage prostate cancer in Canada?

Recently, the PRECISION (PRostate Evaluation for Clinically Important Disease: Sampling Using Image-guidance Or Not?) randomized controlled trial2 and the PROMIS (PROstate Magnetic resonance Imaging Study) prospective paired validation study3 investigated MRI imaging as the first step in evaluating suspected prostate cancer. In the PRECISION trial, 500 men with clinically suspected prostate cancer were randomly allocated across academic and community sites to undergo MRI (with or without targeted biopsy, depending on the MRI findings) or systematic biopsy.2 Magnetic resonance imaging was found to be noninferior to traditional biopsy in the detection of clinically important prostate cancer (38% v. 26%, 95% confidence interval 4%–20%), with the confidence interval indicating superiority of the MRI strategy. Overdiagnosis of clinically unimportant prostate cancer was reduced (9% v. 22%), and biopsy was avoided in 28% of those in the MRI group. In PROMIS, MRI outperformed systematic biopsy in sensitivity (93% v. 48%), negative predictive value (89% v. 74%) and biopsy avoidance for men at low risk (27%), and showed probable cost-effectiveness.3 These findings have prompted consideration of funding for MRI diagnosis in biopsy-naive men with suspected prostate cancer, as well as revision of clinical guidelines, in Canada and beyond.4

However, caution is warranted before considering changing guidelines and health care services. The aforementioned studies included men with higher prostate-specific antigen (PSA) levels (6.8–7.1 ng/mL), and therefore higher pretest probability of cancer, than those in men in contemporary Canadian biopsy cohorts,5 which impairs generalizability of the findings. This effect is evident when reviewing the higher rates of detection of clinically important cancer observed in the PRECISION trial versus those at a tertiary Canadian centre (12%/60%/83% v. 6%/33%/64% for stage 3 [intermediate risk], 4 [high risk] and 5 [very high risk] lesions, respectively, using Prostate Imaging-Reporting and Data System [PI-RADS] version 2).6

Furthermore, poor interobserver reliability and reproducibility are concerning. In the PRECISION trial’s quality-control group, 24/64 men (38%) had discordant classification in MRI grading between local and central review; of the 24 cases, 14 (58%) would have changed management.2 Low interrater agreement may impede clinical decision-making, and patients’ experience of uncertainty and anxiety may erode their confidence in the health care service.7 Until the risk of misclassification (particularly the failure to identify high-risk lesions) decreases, we should be cautious in adopting MRI as the standard of diagnosis. Centralized subspecialist review may be necessary.

Longer-term prognosis and natural history of disease following MRI diagnosis and staging are unknown. Strategies and risk calculators are under development. Questions remain regarding the conversion rate over time from negative to positive MRI findings, the evolutionary potential of PI-RADS stage 1 or 2 (“negative”) lesions and the necessity of repeat or confirmatory testing following negative findings on MRI. Small retrospective studies show wide variability in the progression or regression of lesions and the appearance or disappearance of new lesions on repeat MRI.8 Similarly, for patients with positive MRI findings, consensus on the threshold to biopsy has not been reached: many lesions at PI-RADS stage 3 are indeterminate, with low biopsy yields.2,3

In 2018, the Canadian Agency for Drugs and Technologies in Health reviewed the cost-effectiveness of MRI diagnosis in men with suspected prostate cancer.9 Data heterogeneity and uncertain capacity requirements prevented a clear decision.

Prostate cancer is prevalent, and recommendations for widespread adoption of MRI diagnosis would need to take into account variability in access to MRI services. Magnetic resonance imaging is an investment-, time- and skill-intensive resource. Waiting times in Ontario for nonurgent MRI currently average 2 months, and MRI is completed within provincial targets less than 29% of the time (Appendix 1, available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.190568/-/DC1). Introducing MRI as the standard for prostate cancer diagnosis would likely increase wait times for all, and delays in prostate cancer diagnosis could affect treatment outcomes, especially for patients at high risk.10 If the system is unable to bear an increased demand for MRI diagnosis, core tenets of the Canada Health Act — timely care delivery and accessibility — would be compromised. Uptake of breast MRI has been hampered by similar concerns of high cost, availability and burden to the system, despite evidence of excellent diagnostic accuracy.11

However, thoughtful integration of MRI into the diagnostic algorithm may be possible using a multipillar framework comprising patient risk stratification, MRI order stratification, high-volume centres, efficient protocols and careful knowledge translation. Judicious consideration of patient appropriateness for MRI would help ease demand for testing and ensure that those who could benefit are given priority. Patients at very high risk (PSA level > 20 ng/mL, palpable extraprostatic extension or cT3+) could proceed straight to biopsy and treatment, as MRI will likely not alter management. Similarly, patients with several comorbidities or life expectancy less than 10 years would be unlikely to benefit.

Initially, owing to low availability, MRI diagnosis may be better offered by specialized clinicians and cancer centres to appropriately triage patients who would benefit most from MRI and targeted biopsy (PI-RADS stage 4–5). Performing tests at high-volume centres would accelerate learning and optimize reliability of test interpretation. A randomized trial of active surveillance of prostate cancer showed that the positive predictive value for MRI was 8%–10% at 2 Canadian sites versus 33% at a third, most experienced site.12 Variability in outcomes depends on both MRI interpretation and targeted biopsy performance: if a lesion is identified from specialized radiologic review, adequate communication of MRI series or image number and lesion location to the biopsy performer must follow. Delivery is optimized at high-volume centres, through use of efficient protocols to reduce cost and scanning time, and quality-assurance programs to ensure acceptable aggregate rates. Finally, given that much confusion already exists around screening using PSA, any introduction of MRI as a diagnostic service will require careful knowledge translation and communication across primary care and specialist physicians. Processes should not be needlessly complex or nuanced.

Magnetic resonance imaging has the potential to revolutionize the way we diagnose and manage prostate cancer. Evidence suggests that we can identify and target lesions with increasing accuracy, spare patients unnecessary biopsy, decrease the overdiagnosis and treatment of clinically unimportant cancer, and improve the detection of clinically important cancer. Prebiopsy MRI for suspected prostate cancer is currently under consideration for approval in Canada. However, the long-term impact of this approach remains unknown, and it is not clear that large service changes are currently possible in the Canadian setting. Responsible and practical implementation of MRI diagnosis for prostate cancer in Canada will require patient and MRI order stratification, rollout at high-volume centres and clear knowledge-translation efforts.

Footnotes

  • Competing interests: Antonio Finelli sits on the advisory board for AbbVie, Astellas Pharma, Amgen, Bayer, Janssen Pharmaceutica and TerSera Therapeutics. No other competing interests were declared.

  • This article has been peer reviewed.

  • Contributors: Both authors wrote the commentary, gave final approval of the version to be published and agreed to be accountable for all aspects of the work.

References

  1. ↵
    1. Hodge KK,
    2. McNeal JE,
    3. Terris MK,
    4. et al
    . Random systematic versus directed ultrasound guided transrectal core biopsies of the prostate. J Urol 1989;142: 71–4, discussion 4–5.
    OpenUrlPubMed
  2. ↵
    1. Kasivisvanathan V,
    2. Rannikko AS,
    3. Borghi M,
    4. et al.
    PRECISION Study Group Collaborators. MRI-targeted or standard biopsy for prostate-cancer diagnosis. N Engl J Med 2018;378:1767–77.
    OpenUrl
  3. ↵
    1. Brown LC,
    2. Ahmed HU,
    3. Faria R,
    4. et al
    . Multiparametric MRI to improve detection of prostate cancer compared with transrectal ultrasound-guided prostate biopsy alone: the PROMIS study. Health Technol Assess 2018;22:1–176.
    OpenUrl
  4. ↵
    Prostate cancer: diagnosis and management. NICE guideline [NG131]. London (UK): National Institute for Health and Care Excellence; 2019. Available: https://www.nice.org.uk/guidance/ng131 (accessed 2019 Sept. 27).
  5. ↵
    1. Gorday W,
    2. Sadrzadeh H,
    3. de Koning L,
    4. et al
    . Prostate-specific antigen velocity is not better than total prostate-specific antigen in predicting prostate biopsy diagnosis. Clin Biochem 2015;48:1230–4.
    OpenUrl
  6. ↵
    1. Mathur S,
    2. O’Malley ME,
    3. Ghai S,
    4. et al
    . Correlation of 3T multiparametric prostate MRI using prostate imaging reporting and data system (PIRADS) version 2 with biopsy as reference standard. Abdom Radiol (NY) 2019;44:252–8.
    OpenUrl
  7. ↵
    1. Hansen NL,
    2. Koo BC,
    3. Gallagher FA,
    4. et al
    . Comparison of initial and tertiary centre second opinion reads of multiparametric magnetic resonance imaging of the prostate prior to repeat biopsy. Eur Radiol 2017;27:2259–66.
    OpenUrl
  8. ↵
    1. Ghavimi S,
    2. Abdi H,
    3. Waterhouse J,
    4. et al
    . Natural history of prostatic lesions on serial multiparametric magnetic resonance imaging. Can Urol Assoc J 2018;12: 270–5.
    OpenUrl
  9. ↵
    Magnetic resonance for prostate assessment: a review of clinical and cost-effectiveness. Ottawa: Canadian Agency for Drugs and Technologies in Health; 2018. Available: https://cadth.ca/sites/default/files/pdf/htis/2018/RC1012%20Magnetic%20Resonance%20Imaging%20for%20Prostate%20Assessment%20Final.pdf (accessed 2019 Aug. 1).
  10. ↵
    1. van den Bergh RC,
    2. Albertsen PC,
    3. Bangma CH,
    4. et al
    . Timing of curative treatment for prostate cancer: a systematic review. Eur Urol 2013;64:204–15.
    OpenUrl
  11. ↵
    1. Mango VL,
    2. Goel A,
    3. Mema E,
    4. et al
    . Breast MRI screening for average-risk women: a Monte Carlo simulation cost–benefit analysis. J Magn Reson Imaging 2019;49: e216–21.
    OpenUrl
  12. ↵
    1. Klotz L,
    2. Loblaw A,
    3. Sugar L,
    4. et al
    . Active Surveillance Magnetic Resonance Imaging Study (ASIST): results of a randomized multicenter prospective trial. Eur Urol 2019;75:300–9.
    OpenUrl
PreviousNext
Back to top

In this issue

Canadian Medical Association Journal: 191 (43)
CMAJ
Vol. 191, Issue 43
28 Oct 2019
  • Table of Contents
  • Index by author

Article tools

Respond to this article
Print
Download PDF
Article Alerts
To sign up for email alerts or to access your current email alerts, enter your email address below:
Email Article

Thank you for your interest in spreading the word on CMAJ.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Magnetic resonance imaging diagnosis of prostate cancer: promise and caution
(Your Name) has sent you a message from CMAJ
(Your Name) thought you would like to see the CMAJ web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Magnetic resonance imaging diagnosis of prostate cancer: promise and caution
Douglas C. Cheung, Antonio Finelli
CMAJ Oct 2019, 191 (43) E1177-E1178; DOI: 10.1503/cmaj.190568

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
‍ Request Permissions
Share
Magnetic resonance imaging diagnosis of prostate cancer: promise and caution
Douglas C. Cheung, Antonio Finelli
CMAJ Oct 2019, 191 (43) E1177-E1178; DOI: 10.1503/cmaj.190568
Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like

Jump to section

  • Article
    • Footnotes
    • References
  • Figures & Tables
  • Related Content
  • Responses
  • Metrics
  • PDF

Related Articles

  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Google Scholar

More in this TOC Section

  • Ensuring timely genetic diagnosis in adults
  • The case for improving the detection and treatment of obstructive sleep apnea following stroke
  • Laser devices for vaginal rejuvenation: effectiveness, regulation and marketing
Show more Commentary

Similar Articles

Collections

  • Topics
    • Cancer: prostate
    • Health services
    • Screening & diagnostic tests

 

View Latest Classified Ads

Content

  • Current issue
  • Past issues
  • Collections
  • Sections
  • Blog
  • Podcasts
  • Alerts
  • RSS
  • Early releases

Information for

  • Advertisers
  • Authors
  • Reviewers
  • CMA Members
  • CPD credits
  • Media
  • Reprint requests
  • Subscribers

About

  • General Information
  • Journal staff
  • Editorial Board
  • Advisory Panels
  • Governance Council
  • Journal Oversight
  • Careers
  • Contact
  • Copyright and Permissions
CMAJ Group

Copyright 2023, CMA Impact Inc. or its licensors. All rights reserved. ISSN 1488-2329 (e) 0820-3946 (p)

All editorial matter in CMAJ represents the opinions of the authors and not necessarily those of the Canadian Medical Association or its subsidiaries.

To receive any of these resources in an accessible format, please contact us at CMAJ Group, 500-1410 Blair Towers Place, Ottawa ON, K1J 9B9; p: 1-888-855-2555; e: cmajgroup@cmaj.ca

CMA Civility, Accessibility, Privacy

 

Powered by HighWire