MRI in North America vs Europe
Although prostate cancer is one of the most common cancers worldwide, it is very treatable when caught early. For patients with local to regional prostate cancer (PCa), the 5 year survival rate is nearly 100%, but drops to 30% once the cancer begins to spread to other organs.1 Established organizations like the American Urology Association (AUA), European Association of Urology (EAU) and National Health Service (NHS) have made it their mission to encourage better clinical practice with evidence and expert-based guidelines.2 It is generally accepted that compared to ultrasound, MRI improves the detection of clinically significant prostate cancer, reduces the detection of clinically insignificant cancer and can prevent unnecessary biopsies, yet its recommended use varies between continents. For the most part, all agree MRI should be used for men with an elevated risk of prostate cancer with a prior negative biopsy or biopsy naive men. Swedish and NICE (UK) guidelines extend beyond special cases, offering MRI as the first line of investigation for men with suspected prostate cancer and for those on active surveillance.3,4,5,6 Despite the mounting evidence and recommendations, the actual use of prostate MRI differs vastly between North America and Europe. Based on national surveys, it seems the usefulness of MRI is still out for debate amongst American urologists. Less than half practice pre-biopsy MRI, with the majority of its use limited to special cases like elevated risk and previous negative biopsy. As AUA recommends MRIs be performed at high quality centers, usually academic centers, the cost effectiveness of the MRI pathway and insurance coverage issues remain the primary barriers to implementing pre-biopsy MRI.7 In response, studies like the PROMIS and PRECISION trials intentionally involved academic and nonacademic centres using different MRI systems to evaluate the feasibility of an MRI first pathway. Compared to the Americans, European urologists face similar barriers related to radiological resources, but agree that the value of MRI, and reduction of unnecessary biopsies, outweighs the increased cost of scans. As such, prostate MRI is practiced more often and in many different settings, with widespread use specifically across the UK.2,12
MRI in the UK
In 2016, Prostate Cancer UK and the British Society of Urogenital Radiology submitted a Freedom of Information (FOI) request to health regions to assess the use of pre-biopsy MRI for initial diagnosis and identify barriers to its implementation. Two years later, the UK was the first country in the world to formally recommend MRI scans for prostate cancer.8 The National Health Service of England (NHS) now recommends that all men with suspected prostate cancer should be diagnosed within 28 days, with MRI performed before biopsy.2 Surprising or not, many trusts have risen to the challenge and transformed their diagnostic pathway with fast-track service, some even performing same day MRI with or without biopsy.12
Each year, a quarter of a million men in Europe will avoid biopsy.12 Although the number of hospitals providing multiparametric MRI (mpMRI) has risen to nearly 99%, only half are capable of delivering high-quality MRIs. This is due to outdated equipment, not enough experienced radiologists and a lack of detailed guidance on how to use MRI reports in clinical decision making. National efforts have been made to address these issues. In support of radiologists and clinicians, the UK held a consensus meeting that set criteria, identifying the quality, setting and role of mpMRI in the diagnostic pathway.9,10,11 More recently, resources have gone into educating radiologists on scanner setup and PI-RADS. Without a pre-installed prostate tissue setting, each MRI machine must be fine tuned individually. An online community forum has helped hospitals share knowledge on optimizing MRI sequences/ scanners. In a joint effort, hospitals, Prostate Cancer UK and the Royal College of Radiologists have organized training courses, mentoring and site visits to help radiologists gain experience reading prostate MRI scans. They are also working on a way to remotely help hospitals set up their scanners.10,12
The Future Role of MRI in the UK
After leading the TRexit 2020 movement, the UK continues to pave the way towards better prostate cancer care with the IP7-PACIFIC (Imperial Prostate 7- Prostate Assessment using Comparative Interventions for Cancer) trial. Awarded £1 million by Cancer Research UK, the team from Imperial College London and Imperial College Healthcare NHS Trust will investigate if bi-parametric MRI (bpMRI) is an efficient, cost-effective alternative to multi-parametric MRI (mpMRI). With prostate cancer cases on the rise, it is predicted that 63,000 men will be diagnosed every year by 2030. That means about a quarter of a million scans will need to be eventually carried out annually. Existing evidence shows comparable accuracy in diagnosing cancer, but the studies have not been of high quality or large enough to change NHS practice.13,14
IP7-PACIFIC Trial
Up to 30 NHS hospitals will participate in the IP7-PACIFIC trial, drawing in an expected 3,600 participants. The first arm of the study will compare bpMRI to mpMRI for the detection of clinically significant cancer. Long MRI, or mpMRI, usually takes 30-40 minutes and uses gadolinium (dye) that helps visualize organs more clearly. Due to the risk of allergy, the injection of dye requires additional medical supervision, leading to longer procedural times. On the flip side, short MRI, or bpMRI only takes 15-20 minutes, doesn’t use dye and is about half the cost (£200 vs £350- £450). The secondary arm will compare 2 methods of targeted biopsy: visual registration and image fusion. During visual or cognitive registration, the urologist is guided by live ultrasound on one screen, while looking at the MRI displayed on a separate screen. Using their best judgment, they visually guesstimate where the regions of interest are (from the MRI), relative to the probe (shown on ultrasound). The accuracy relies heavily on the experience of the physician. Additional samples may be taken from other healthy looking areas of the prostate to ensure cancer is not missed. Alternatively, targeted biopsy may be performed using a fusion system, like the Fusion Bx, where the urologist is guided by software, rather than best judgement. On a single screen, the software shows a 3D model of the prostate, the regions of interest, and where the probe and needle are pointing. To achieve this, the fusion software overlays MRI scans with live ultrasound to create a 3D reconstruction of the prostate, while a stepper device spatially tracks the probe in real-time. In essence, the software does the same thing as the urologist in visual registration, but uses landmarks and algorithms to accurately account for any prostate deformation or movement. This lowers the barrier for less experienced physicians and helps make procedures more consistent across the board. Device setup and image registration process means the procedure usually takes a few minutes longer to perform. Studies over the past 5 years have shown mixed results; most say both methods are comparable, whilst few others suggest image fusion makes a significant difference in detecting clinically significant prostate cancer. 13,14
The Outcome
The UK has shown optimizing the diagnostic pathway is a joint effort, but most importantly starts with the right attitude. Initiatives like training programs, mentoring, streamlined clinical service and funded research are key to better prostate cancer care. If bpMRI can detect cancer just as effectively as mpMRI, it could save up to £15 million per year. Not only does this save the NHS money, but it will also allow for more men to be scanned. A faster, cheaper and more accessible MRI means easier adoption and better access to targeted biopsies. Whether or not the NHS adopts image fusion in all hospitals doing prostate biopsies will depend on the results of the trial.13,14
1 Panzone, J., Byler, T., Bratslavsky, G., Goldberg, H. (2022). Transrectal Ultrasound in Prostate Cancer: Current Utilization, Integration with mpMRI, HIFU and Other Emerging Applications. Cancer Management and Research, 2022(14), 1209- 1228. https://doi.org/10.2147/CMAR.S265058
2 Giganti, F., Rosenkrantz, A. B., Villeirs, G., Panebianco, V., Stabile, A., Emberton, M., & Moore, C. M. (2019). The evolution of MRI of the prostate: The past, the present, and the future. American Journal of Roentgenology, 213(2), 384–396. https://doi.org/10.2214/ajr.18.20796
3 EAU. (2022). EAU guidelines on prostate cancer – diagnostic evaluation. Uroweb. https://uroweb.org/guidelines/prostate-cancer/chapter/diagnostic-evaluation
4 Bjurlin, M. A., Carroll, P. R., Eggener, S., Fulgham, P. F., Margolis, D. J., Pinto, P. A., Rosenkrantz, A. B., Rubenstein, J. N., Rukstalis, D. B., Taneja, S. S., & Turkbey, B. (2020). Update of the standard operating procedure on the use of multiparametric magnetic resonance imaging for the diagnosis, staging and management of prostate cancer. Journal of Urology, 203(4), 706–712. https://doi.org/10.1097/ju.0000000000000617
5 Overview: Prostate cancer: Diagnosis and management: Guidance. NICE. (2019, May 9). https://www.nice.org.uk/guidance/ng131
6 Bratt, O., Carlsson, S., Fransson, P., Thellenberg Karlsson, C., Stranne, J., & Kindblom, J. (2022). The Swedish national guidelines on Prostate cancer, part 1: Early detection, diagnostics, staging, patient support and primary management of non-metastatic disease. Scandinavian Journal of Urology, 56(4), 265–273. https://doi.org/10.1080/21681805.2022.2094462
7 Tooker, G. M., Truong, H., Pinto, P. A., & Siddiqui, M. M. (2019). National survey of patterns employing targeted MRI/US guided prostate biopsy in the diagnosis and staging of prostate cancer. Current Urology, 12(2), 97–103. https://doi.org/10.1159/000489426
8 Davies, C., Castle, J. T., Stalbow, K., & Haslam, P. J. (2019). Prostate mpmri in the UK: The State of the Nation. Clinical Radiology, 74(11). https://doi.org/10.1016/j.crad.2019.09.129
9 Brizmohun Appayya, M., Adshead, J., Ahmed, H. U., Allen, C., Bainbridge, A., Barrett, T., Giganti, F., Graham, J., Haslam, P., Johnston, E. W., Kastner, C., Kirkham, A. P. S., Lipton, A., McNeill, A., Moniz, L., Moore, C. M., Nabi, G., Padhani, A. R., Parker, C., … Punwani, S. (2018). National implementation of multi-parametric Magnetic Resonance Imaging for Prostate Cancer Detection – recommendations from a UK consensus meeting. BJU International, 122(1), 13–25. https://doi.org/10.1111/bju.14361
10 Roberts, K. (2021, April 12). Prostate cancer MRI scans: Is the NHS ready? Cancer Research UK . https://news.cancerresearchuk.org/2019/05/09/prostate-cancer-mri-scans-is-the-nhs-ready/
11 Stroman, L., Cathcart, P., Lamb, A., Challacombe, B., & Popert, R. (2021). A cross‐section of UK prostate cancer diagnostics during the coronavirus disease 2019 (Covid‐19) era – a shifting paradigm? BJU International, 127(1), 30–34. https://doi.org/10.1111/bju.15259
12 Prostate MPMRI before biopsy – case studies from 5 NHS trusts. Prostate Cancer UK. (n.d.). https://prostatecanceruk.org/for-health-professionals/best-practice-and-innovation/mpmri-case-studies
13 Myers, M. (2022, January 13). Researchers awarded £1m to trial quicker diagnostic tools for prostate cancer. Imperial College London. https://www.imperial.ac.uk/news/233114/researchers-awarded-1m-trial-quicker-diagnostic/
14 Imperial College London. (2022, October 10). Imperial Prostate 7 – Prostate Assessment Using Comparative Interventions – Fast Mri and Image-fusion for Cancer (IP7-PACIFIC). https://clinicaltrials.gov/ct2/show/NCT05574647