Whole-body MRI may detect spread of cancers more quickly

Whole-body MRI could reduce the time it takes to diagnose the stage of colorectal and non-small cell lung cancer in new patients, according to two prospective trials with nearly 500 patients across 16 UK hospitals.

Appropriate treatment cannot be decided upon until the size of a tumour and the extent to which it has spread to nearby lymph nodes and other parts of the body has been determined. Standard NHS pathways often involve different imaging techniques — such as CT, PET-CT or focused MRI scans — which vary in accuracy in different organs. Several appointments and follow-up examinations can therefore be necessary.

Now, UK researchers have compared the diagnostic accuracy and efficiency of whole-body MRI with the standard NHS pathways, which use a range of imaging techniques for assessing colorectal and lung cancers. The results were published in the journals The Lancet Gastroenterology & Hepatology and The Lancet Respiratory Medicine.

The standard imaging tests recommended by The National Institute for Health and Care Excellence (NICE) were undertaken and the usual multidisciplinary panel made a first treatment decision based on their results. Once this decision had been recorded, they considered images and reports from whole-body MRI. If the latter highlighted a need for further tests, these were carried out. The panel were then able to say whether their first treatment decision would have been different based on the whole-body MRI result. In the interests of patient care, the final decision was made based on results from all tests.

Patients were also followed up after 12 months to better evaluate the accuracy of whole-body MRI compared with standard tests; for example, whether one approach was more sensitive than the other in detecting spread of the primary tumour to other parts of the body. Based on this data, the panel were able to retrospectively evaluate what the optimal treatment decision should have been.

The use of whole-body MRI reduced the time it took to complete diagnostic tests, from an average of 13 days to an average of eight days in the colorectal cancer trial and from 19 days to 13 days in the lung cancer trial. Costs were reduced from an average of £285 to £216 in the colorectal cancer trial and from an average of £620 to £317 in the lung cancer trial.

Sensitivity and specificity of diagnosis for whole-body MRI did not differ from standard tests for both cancers. In the colorectal cancer trial, agreement with the final multidisciplinary panel treatment decision based on standard investigations and whole-body MRI was similar and high (95% and 96%, respectively), as were results for the lung cancer trial (99% for standard investigations and 98% for whole-body MRI).

“Our results, obtained in a real-world NHS setting, suggest that whole-body MRI could be more suitable for routine clinical practice than the multiple imaging techniques recommended under current guidelines,” said lead author Professor Stuart Taylor, from University College London. “While demands on NHS MRI scanners is currently high, MRI can image the whole body in one hour or less. Adopting whole-body MRI more widely could save rather than increase costs, as well as reducing the time before a patient’s treatment can begin.”

The authors note that their findings are specific to colorectal and non-small cell lung cancer and might not be relevant to tumours arising in other parts of the body. In addition, waiting times might not be representative of other UK hospitals or of hospitals in other countries; in fact, many of the hospitals were not able to find time on their MRI scanners, meaning that patients were examined in nearby hospitals.

A further limitation of the lung cancer trial is that sensitivity in detecting the spread of cancers — including the development of secondary tumours and the spread to lymph nodes — was low using both current standard imaging techniques and whole-body MRI. Further research is thus needed to improve the performance of non-invasive imaging.

Image credit: ©iStockphoto.com/Mark Kostich

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