Clinicians should consider whole-body MRI to save time, costs when staging cancer patients

Whole-body MRI (WB-MRI) staged colorectal and lung cancer patients with accuracy similar to standard staging pathways, but WB-MRI saved valuable time and costs associated with screening, according to two newly published prospective trials of nearly 500 patients.

WB-MRI, compared to standard imaging, reduced the average time to determine tumor size and metastasis by six days for lung cancer and five days for colorectal cancer (CRC), according to the trials published May 9 in The Lancet Respiratory Medicine and The Lancet Gastroenterology & Hepatology.

Taken together, the results of both trials suggest WB-MRI is on par with the accuracy of CT, PET, site-focused MRI and ultrasound, and may push clinicians to consider WB-MRI in place of standard imaging tests, according to lead author Stuart Taylor, MD, of the Centre for Medical Imaging at University College London, and colleagues.

Our results, obtained in a real-world NHS (National Health Services) setting, suggest that whole body MRI could be more suitable for routine clinical practice than the multiple imaging techniques recommended under current guidelines,” Taylor added, in a news release. “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.”

In the CRC trial—named Streamline C—Taylor and colleagues recruited 370 newly diagnosed CRC patients 18 years or older from across 16 hospitals in England. The patients underwent WB-MRI and results were withheld until they completed standard staging tests. A multidisciplinary team made treatment decisions based on standard investigations, then using WB-MRI staging pathways (WB-MRI plus additional tests) and ultimately using all tests.

The final cohort included 299 patients—96% of cases were staged at T2 or above. In that group, pathway sensitivity was 67% for WB-MRI compared to 63% for standard pathways—a nonsignificant difference, the authors noted. Specificity between both methods was also similar. In WB-MRI that was 95% compared to 93% was standard pathways.

Additionally, agreement with the multidisciplinary team’s final treatment was 96% for WB-MRI and 95% for standard pathway. The mean per-patient staging costs were £216 ($282 USD) for WB-MRI and £285 ($372) for standard pathways. Time to complete staging using WB-MRI was a median of 8 days, down from the 13 days needed for traditional pathways. WB-MRI also required fewer tests than did standard pathways.

Lung cancer trial

In the Streamline L trial, researchers recruited 353 patients with newly diagnosed non-small cell lung cancer (NSCLC) across 16 English hospitals from February 2013 to September 2016. The final group of 187 patients underwent similar imaging and procedures as patients in the CRC trial. A total of 73% of cases were staged at T2 or higher.

Results showed a pathway sensitivity of 50% for WB-MRI, a nonsignificant difference from that seen in standard methods (54%). Both methods achieved a 93% specificity. Agreement with the multidisciplinary teams treatment decisions resulted in a 1% difference between both pathways, with WB-MRI scoring higher at 99%.

Time to complete staging dropped when using WB-MRI, from 19 days down to 13 days. Mean per-patients costs were £317 ($356 USD) for WBI-MRI and £620 ($808) for standard pathways. The number of tests required were similar for each method.

In an editorial accompanying the CRC trial results, Andreas G. Schreyer, of Brandenburg University Hospital’s Department of Radiology in Germany, wrote that MRI has often been overlooked, but the results presented in both trials prove that the medical community should never rule out all options.

“MRI has faced considerable backlash within the medical community due to relatively high costs and the problems involved in finding a timely slot for imaging because of the high demand for this method,” Schreyer added. “This is why it is particularly important to think outside the box and look out for new medical pathways and paradigms and not to be driven by prejudices. It could be more efficient to adapt the known therapeutic concept of hitting hard and early to diagnostic imaging to improve medical outcomes and economic performance.”