Whole-body MRI spots metastatic disease in newly diagnosed lung, colorectal cancer

Last Updated: 2019-06-10

By Will Boggs MD

NEW YORK (Reuters Health) - Compared with standard diagnostic pathways, whole-body MRI detects metastatic disease in newly diagnosed non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC) faster, more cheaply and with similar accuracy, according to findings from the Streamline L and Streamline C trials.

"For the first time in a prospective-multicenter-study setting, whole-body (WB)-MRI has been shown to be a viable and desirable replacement to standard staging in colorectal and non-small-cell cancer, reducing staging times, test number, and costs while achieving the same diagnostic accuracy and treatment decisions as current standard multi-modality staging pathways," said Dr. Stuart A. Taylor from University College London's Center for Medical Imaging.

"As such, we need to invest in MRI capacity and radiologist expertise to accommodate expanding use of WB-MRI," he told Reuters Health by email.

Identification of metastatic disease is an important objective during staging for NSCLC for CRC, because this typically dictates the therapeutic strategy.

Dr. Taylor and colleagues compared the diagnostic accuracy and efficiency of WB-MRI-based staging pathways with standard staging in 187 patients with newly diagnosed NSCLC (Streamline L) and in 299 patients with newly diagnosed CRC (Streamline C).

The primary outcome in both studies was the per-patient sensitivity for metastatic disease detection between standard and WB-MRI staging pathways, compared against the consensus reference standard. The result of WB-MRI was withheld until standard staging investigations were complete and the first treatment decision made.

In Streamline L, staging sensitivity was 50% for WB-MRI and 54% for standard pathways (P=0.73), and specificity was 93% for the WB-MRI pathway and 95% for the standard pathway (P=0.45), the researchers report in The Lancet Respiratory Medicine, online May 9.

Median time to staging of NSCLC was significantly shorter for WB-MRI pathways than for standard pathways (13 days vs. 19 days), and mean per-patient costs were significantly lower ( 317 vs. 620).

"Although WB-MRI might be the imaging modality we have been hoping for in NSCLC staging, occult metastases and lymph node staging remain challenging by non-invasive imaging," an accompanying editorial notes.

"Further research is needed to improve the diagnostic performance of non-invasive imaging, preferably a one-stop-shop approach, which allows time-efficient and accurate treatment decisions," write Dr. Mathias Meyer of Duke University Medical Center, in Durham, North Carolina, and Dr. Johannes Budjan of Heidelberg University in Mannheim, Germany.

In Streamline C, online May 9 in The Lancet Gastroenterology and Hepatology, sensitivity and specificity of staging for patients with metastatic disease did not differ significantly between WB-MRI (67% and 95%, respectively) and standard pathways (63% and 93%, respectively).

Median time to staging of CRC was significantly shorter for WB-MRI pathways (eight days) than for standard pathways (13 days), and mean per-patient costs were significantly lower for the WB-MRI pathway ( 216) than for the standard staging pathway ( 287).

"It is generally assumed that WB-MRI is an expensive test," Dr. Taylor said. "It was, therefore, interesting that for both cancers the WB-MRI staging pathway came out cheaper than the standard pathway."

"We know patients prefer tests that do not expose them to ionizing radiation," he said. "By reducing radiation exposure, WB-MRI is an attractive first-line option in younger patients diagnosed with cancer, and such an approach would allow a service to build up its infrastructure before extending its WB-MRI staging service."

Dr. Taylor added, "An important consideration for any new technology is patient acceptability. Our data suggests that most patients prefer WB-MRI to standard staging pathways if they reduce the time to staging and test number. The Streamline trials showed WB-MRI does exactly this."

Dr. Andreas G. Schreyer from Brandenburg Medical School, in Germany, who wrote an editorial accompanying the Streamline C report, told Reuters Health by email, "Based on the data published, WB-MRI should replace the conventional standard pathways immediately for patients with colorectal carcinoma. But there are practical problems, which occurred even within the study setting: a lot of hospitals did not have sufficient MRI equipment or radiological personal to cope with the demand. This will be the real problem: not enough radiologists for reading and not enough MRI scanners for acquiring the examinations."

"Physicians should not have prejudices towards new, advanced, and on the first sight expensive examinations - it is important to walk new pathways and evaluate the new, undiscovered paths in diagnosis," he said. "I consider this 'real world study' extremely important to improve further diagnostic pathways; (it's) open minded regarding a better and at the same time economically more efficient diagnosis and treatment."

Dr. Kim Sivesgaard from Aarhus University Hospital, in Denmark, who was not involved in the studies, has compared the accuracy of contrast-enhanced CT, MRI, and FDG PET/CT for detecting colorectal-cancer liver metastases He told Reuters Health by email, "If the findings can be confirmed in other studies and availability issues with respect to MRI capacity are resolved, WB-MRI as the first-line staging tool could be used for all newly diagnosed colorectal-cancer patients."

"In a more general perspective, the most important message is that new imaging techniques should not necessarily just be added to existing work pathways but should be considered as possible replacements when relevant," he said.

Dr. Sivesgaard added, "Less than one-third of eligible patients were included. Part of this was due to no available MRI scan slots within 3 weeks. This emphasizes the need to consider the availability of WB-MRI, i.e., that the number of MRI scanners must be increased if this relatively time consuming use of MRI capacity is expanded to all newly diagnosed colorectal cancer patients."

SOURCE: https://bit.ly/2K9yY8b and https://bit.ly/2M9hiMj

Lancet Respir Med 2019.

https://bit.ly/2Wa63Ig and https://bit.ly/30QCUQY

Lancet Gastroenterol Hepatol 2019.