Trials with people with newly diagnosed colorectal and non-small cell lung cancer suggest that whole-body MRI could reduce the time it takes to diagnose the stage of cancers. The results are from two prospective trials, with nearly 500 patients across 16 UK hospitals.
Whole-body MRI scans reduced the average time to determine the size of tumors and how much they had spread by five days for colorectal cancer patients and six days for lung cancer patients. The treatments decided upon were similar, since results from MRI were as accurate as from standard investigations, but the costs per patient were reduced by nearly one-quarter in the case of colorectal cancer and were almost halved for lung cancer.
Despite their accuracy and efficiency, the authors note that MRI scanners are not as widely available as other imaging technologies and are in high demand. In the trials, many of the hospitals were not able to find time on their MRI scanners, meaning that patients were examined in nearby hospitals.
For the first time, however, the two new trials are comparing the diagnostic accuracy and efficiency of whole-body MRI with the standard NHS England pathways, which use a range of imaging techniques for assessing colorectal and lung cancers. The standard imaging tests recommended by the National Institute for Health and Care Excellence were undertaken as usual 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, such tests were executed. The panel were then able to say whether their first treatment decision would have 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 instance, whether one approach was more sensitive than the other in detecting the spread of the primary tumor to other parts of the body. Based on this data, the panel could retrospectively evaluate what the optimal treatment decision should have been.
Moreover, sensitivity and specificity of diagnosis for whole-body MRI did not differ from standard tests for both cancers. Also, 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.
In the colorectal cancer trial, agreement with the final multi-disciplinary 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).
Eight of the 16 hospitals in the colorectal cancer trial and 11 of the 16 hospitals in the lung cancer trial did not have the infrastructure to perform whole-body MRI.
The authors note that their findings are specific to colorectal and non-small cell lung cancer and might not be relevant to tumors 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. A further limitation of the lung cancer trial is that sensitivity in detecting the spread of cancers—including the development of secondary tumors and the spread to lymph nodes—was low using both current standard imaging techniques and whole-body MRI. Further research is needed to improve the performance of non-invasive imaging.
