What can whole-body MR mean for staging cancer more efficiently?
November 08, 2019
by Gus Iversen
, Editor in Chief
A group of researchers in the U.K. have found that whole-body MR (WB-MR) imaging may reduce the time required for staging and planning cancer treatment, based on two prospective trials.
We spoke with Stuart Taylor, researcher and professor of medical imaging at University College London, to learn more about whole-body MR and the benefits it could bring to healthcare.
HCB News: How is WB-MR distinguished from conventional MR?
Stuart Taylor: WB-MR uses standard MR machines and sequences, so can be implemented on most modern MR machines widely available in many healthcare systems. The scan covers most of the body, usually from head to mid-thigh so it is typically used in diseases which can affect any part of the body, with cancer staging being the most common indication.
Due to the pressures on scanner capacity and to improve patient experience, WB-MR scans are usually designed to take a maximum of an hour to acquire, although it is possible to scan using much shorter times. The concept is that the scan is good enough to detect important abnormalities without the high level of detail provided by scans tailored to one individual organ.
HCB News: What types of patients are best suited for whole-body MR scans?
ST: WB-MR has been used for staging many cancer types including myeloma, breast cancer and prostate cancer. Although the evidence behind its use in these tumours is very promising, studies are usually relatively small, limited to single hospitals with scans interpreted by very experienced radiologists.
The Streamline trials were the first large prospective multicenter studies of WB-MR where scans were performed and interpreted exactly as they would be in routine clinical practice. WB-MR was performed to stage colorectal cancer and lung cancer. The trials found that WB-MR was just as good as conventional scans (such as CT and PET/CT), but staging pathways were quicker and less scans were needed.
HCB News: Your research found that the whole-body MR pathways were quicker and cheaper in the NHS setting than conventional approaches. Are there specific characteristics of the NHS setting that may factor into those findings?
ST: This finding was based on standard tariff costs used in the English NHS, and on typical waiting times in NHS hospitals. It does assume that WB-MR can be performed within a reasonable time, usually within two weeks of request. Thus, hospitals need to have capacity on MR machines to achieve this. The costs of scans differ across healthcare systems so the cost savings my not necessarily hold true in other countries.
HCB News: Based on your research, was there a significant learning curve for radiologists to become comfortable and competent using whole-body MR?
ST: Like any complex imaging technique, there is a learning curve in interpretation, and performance improves with experience. We wanted to test how WB-MR would work if disseminated in the NHS. We, therefore, did not restrict our reporting radiologists to a handful of experts. Instead we used radiologists who were trained as they would be if they were starting up a WB-MR service at their hospital.
They therefore had access to a database of images which they had to review, and then, when they started reporting they initially had their reports checked by a more experienced radiologist, until they were deemed competent to report alone.
HCB News: Aside from establishing the evidence, what needs to take place for whole-body MR to become a viable option for patients?
ST: Perhaps the biggest logical barrier to wider dissemination of WB-MR is space on MR scanners, which are usually already running at near capacity. However, given the potential cost savings of using first line WB-MR staging, it should be possible to provide a compelling business case to increase MR capacity in the NHS.
HCB News: Are there other indications where whole body MR might prove more efficient than conventional staging pathways?
ST: The National Institute for Health and Care Excellence now recommends WB-MR as an alternative to CT and PET/CT for staging myeloma. In other cancers such as prostate cancer, consensus guidelines recommend including WB-MR in trial designs of new therapeutics so its clinical utility can be fully assessed.