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Whole-body MRI may facilitate lung cancer staging

Using whole-body magnetic resonance imaging for staging in non-small-cell lung cancer reduced staging time, cut costs and had similar diagnostic accuracy when compared with current standard cancer staging pathways, according to a study published in The Lancet Respiratory Medicine.

In the Streamline L trial, pathway sensitivity for whole-body MRI (50%; 95% CI, 37-63) and standard pathways (54%; 95% CI, 41-67) differed by 4% (P = .73). Specificity was also comparable between whole-body MRI (93%; 95% CI, 88-96) and standard pathways (95%; 95% CI, 91-98; P = .45).

A multidisciplinary team first determined treatment based on standard pathways and then on whole-body MRI scans. The final treatment decision was made after considering all evidence. For whole-body MRI, agreement with the final treatment decision was 98% and for standard pathways agreement was 99%.

Time to complete staging was also reduced from an average of 19 days with standard pathways to 13 days with whole-body MRI. The mean per-patient cost with whole-body MRI was nearly half that of standard pathways (£317 vs. £620).

No adverse events related to imaging were reported during the trial.

“Our results, obtained in a real-world NHS (UK National Health Service) setting, suggest that whole-body MRI could be more suitable for routine clinical practice than the multiple imaging techniques recommended under current guidelines,” Stuart Taylor, MD, FRCR, professor of medical imaging at University College London in the United Kingdom, said in a press release. “While demands on NHS MRI scanners is currently high, MRI can image the whole body in 1 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.”

Additional findings

The study enrolled adults with newly diagnosed non-small-cell lung cancer that was stage IIIb or less at 16 hospitals in England. The final study cohort included 187 patients with a median age of 67 years, of whom 37% were women. Nearly three-quarters (73%) were stage T2 or above, 41% were node-positive and 28% had metastatic disease at the time of staging. Follow-up occurred after 12 months.

In addition to the main findings on sensitivity and specificity, results also showed that whole-body MRI staging had 82% sensitivity for patients whose largest metastasis was at least 1 cm, which was not significantly different from the 75% seen with standard pathways, but only 9% for smaller metastasis, the researchers noted. When used as a standalone investigation, whole-body MRI had similar sensitivity but lower specificity than the standard pathways.

There was a significant 10% difference in agreement for N stage between whole-body MRI and standard pathways (65% vs. 75%), which persisted in the 109 of 187 patients with histological proof of N stage. Pathways did differ significantly in agreement for T stage.

Standard staging pathways involved 302 individual investigations and whole-body MRI involved 232 individual investigations, but the median number of additional tests did not differ between whole-body MRI and standard pathways.

Unanswered resolved issues

Despite the positive findings, Taylor and colleagues emphasized that these data are not yet generalizable to every population.

“Further research is needed to define the potential use of [whole-body MRI] in the assessment of treatment response and post-therapy surveillance for recurrent disease,” the researchers wrote. “Our findings are specific for [non-small-cell lung cancer] and might not be relevant to other primary tumor sites.”

In a linked comment, Mathias Meyer, MD, and Johannes Budjan, MD, both from the Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim and Heidelberg University, Germany, agreed that the study represents a step forward. However, there are other issues to consider.

For instance, occult metastatic disease at baseline is still a problem, particularly in light of the low sensitivity of both pathways for metastatic staging; current imaging modalities are insufficient for lymph node staging; contraindications to whole-body MRI would restrict its usage; and there remains controversy over use of gadolinium-based agents, they noted.

“Although [whole-body] MRI might be the imaging modality we have been hoping for in [non-small-cell lung cancer] staging remains challenging by non-invasive imaging,” they wrote. “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.”– by Melissa Foster

Disclosures: Taylor reports he has received consultancy fees from Robarts Plc. Please see the study for a list of all other authors’ relevant financial disclosures. Meyer reports he has received speaking fees from Siemens Healthineers and he has received grants to his institution from Bracco Imaging and Siemens Healthineers. Budjan reports he has received speaking fees from Ferring Pharmaceuticals and Siemens Healthineers.