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NIHR Signal Whole-body MRI scans are as accurate as standard imaging pathways for lung cancer staging

Published on 23 July 2019

doi: 10.3310/signal-000796

Using whole-body magnetic resonance imaging (MRI) in the initial investigation pathway is as good as standard pathways for detecting metastatic disease in adults with non-small-cell lung cancer. This NIHR-funded study also found that WB-MRI used for diagnosis and staging is quicker, cheaper and requires fewer other investigations than standard pathways.

Although patients reported that having whole-body MRI was a greater burden than standard imaging, they generally preferred whole-body MRI if it reduced staging times. In theory, it may also reduce radiation exposure, as most people would not need to have a positron-emission tomography CT scan.

Current NICE guidance recommends a sequence of investigations for staging – assessing the extent of cancer in order to plan appropriate treatment. MRI of different areas of the body is only recommended after other imaging investigations. This study suggests that whole-body MRI could have a role earlier in the pathway.  

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Why was this study needed?

There are about 47,200 new cases of lung cancer in the UK every year. Most of these are non-small-cell lung cancer, which spreads more slowly than small-cell lung cancer. Staging is the process of determining what ‘stage’ the cancer has reached, based on the extent of any spread. 

Current staging pathways are complex, lengthy and resource-intensive as they use different techniques for various parts of the body, though most patients have a PET-CT scan. They are not yet ideal, as around 20% of people who have curative surgery relapse because of metastases that were not picked up before the operation.

Whole-body MRI is an alternative to current imaging techniques, but it was not known how accurate it is for all lung metastases. Previous research was limited to comparing whole-body MRI against one other technique only, or by looking for metastases in just one part of the body.

This study aimed to compare the diagnostic accuracy and efficiency of a whole-body MRI staging pathway with current staging pathways, including cost analysis.

What did this study do?

This diagnostic accuracy study included 187 adults diagnosed with non-small-cell lung cancer from 16 hospitals in the UK. All had stage IIIb or less according to their initial diagnostic chest CT scan, so were potentially eligible for curative treatment. Participants had whole-body MRI, as well as the standard staging investigations.

Initial treatment decisions were recorded using only standard care investigations. Next, the clinicians recorded their treatment plan just based on the whole-body MRI and any additional tests they felt necessary, arranged if not already performed. Final treatment decisions were based on all the investigations.

The opinion of an expert multidisciplinary review panel on staging, based on all initial investigations and follow-up data at 12 months, was used as the reference diagnostic standard to compare the staging recorded by both pathways.

What did it find?

  • Pathways were similarly poor at correctly finding metastatic disease in people with the disease (sensitivity) which was 50% for whole-body MRI compared to 54% for standard pathways (difference ‑4%, 95% confidence interval [CI] ‑15% to 7%). This reflects how difficult it can be to detect small metastases early on.
  • Both pathways were reasonably good at correctly identifying those who did not have metastases (specificity) which was 93% for whole-body MRI compared to 95% for standard pathways (difference ‑2, 95% CI ‑7% to 2%).
  • Agreement with the multidisciplinary team’s final treatment decision by the consensus expert panel review at 12 months was 98% for whole-body MRI and 99% for standard pathways.
  • Time taken to complete staging investigations was shorter for whole-body MRI than standard pathways: 13 days (95% CI 12 to 14 days) compared with 19 days (95% CI 17 to 21 days). This reduced staging time was important to patients.
  • Mean costs per patient were £317 for whole-body MRI (95% CI £273 to £361), versus £620 for standard pathways (95% CI £574 to £666) as fewer other investigations were required.

What does current guidance say on this issue?

NICE guidance published in March 2019 says that people with known or suspected lung cancer should be offered a contrast-enhanced chest CT scan. Other techniques such as ultrasound should be considered if there is doubt. A positron-emission tomography CT should be offered before any potentially curative treatment. It says that MRI should not be routinely used to assess the stage of the primary tumour in non-small-cell lung cancer. In its recommendations for further staging, it says that the presence of metastases should be confirmed by biopsy or further imaging, for example, MRI.

What are the implications?

This study suggests that using whole-body MRI in the initial pathway has similar accuracy for diagnosis, staging and planning treatment of non-small-cell lung cancer.

As clinicians only wanted the results of the positron-emission tomography CT scan for 14% of the WB-MRI group to inform treatment decisions, this means that most people would not need to be exposed to the radiation that CT uses. Fewer investigations and faster staging would be beneficial for both patients and the NHS.

The approach of the study suggests that it reflects how imaging is carried out and interpreted in UK hospitals. Implementation may need some additional training of staff to cope with the number of people who might need whole-body MRI.

Citation and Funding

Taylor S, Mallett S, Ball S et al. Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed non-small-cell lung cancer: the prospective Streamline L trial. Lancet Respir Med. 2019;7:523-32.

This project was funded by the NIHR Health Technology Assessment Programme (project number 10/68/01).

Bibliography

Cancer Research UK. Lung cancer statistics. London: Cancer Research UK; accessed 23 July 2019.

NHS website. Lung cancer. London: Department of Health and Social Care; 2015.

NICE. Lung cancer: diagnosis and management. NG122. London: National Institute for Health and Care Excellence; 2019.

Why was this study needed?

There are about 47,200 new cases of lung cancer in the UK every year. Most of these are non-small-cell lung cancer, which spreads more slowly than small-cell lung cancer. Staging is the process of determining what ‘stage’ the cancer has reached, based on the extent of any spread. 

Current staging pathways are complex, lengthy and resource-intensive as they use different techniques for various parts of the body, though most patients have a PET-CT scan. They are not yet ideal, as around 20% of people who have curative surgery relapse because of metastases that were not picked up before the operation.

Whole-body MRI is an alternative to current imaging techniques, but it was not known how accurate it is for all lung metastases. Previous research was limited to comparing whole-body MRI against one other technique only, or by looking for metastases in just one part of the body.

This study aimed to compare the diagnostic accuracy and efficiency of a whole-body MRI staging pathway with current staging pathways, including cost analysis.

What did this study do?

This diagnostic accuracy study included 187 adults diagnosed with non-small-cell lung cancer from 16 hospitals in the UK. All had stage IIIb or less according to their initial diagnostic chest CT scan, so were potentially eligible for curative treatment. Participants had whole-body MRI, as well as the standard staging investigations.

Initial treatment decisions were recorded using only standard care investigations. Next, the clinicians recorded their treatment plan just based on the whole-body MRI and any additional tests they felt necessary, arranged if not already performed. Final treatment decisions were based on all the investigations.

The opinion of an expert multidisciplinary review panel on staging, based on all initial investigations and follow-up data at 12 months, was used as the reference diagnostic standard to compare the staging recorded by both pathways.

What did it find?

  • Pathways were similarly poor at correctly finding metastatic disease in people with the disease (sensitivity) which was 50% for whole-body MRI compared to 54% for standard pathways (difference ‑4%, 95% confidence interval [CI] ‑15% to 7%). This reflects how difficult it can be to detect small metastases early on.
  • Both pathways were reasonably good at correctly identifying those who did not have metastases (specificity) which was 93% for whole-body MRI compared to 95% for standard pathways (difference ‑2, 95% CI ‑7% to 2%).
  • Agreement with the multidisciplinary team’s final treatment decision by the consensus expert panel review at 12 months was 98% for whole-body MRI and 99% for standard pathways.
  • Time taken to complete staging investigations was shorter for whole-body MRI than standard pathways: 13 days (95% CI 12 to 14 days) compared with 19 days (95% CI 17 to 21 days). This reduced staging time was important to patients.
  • Mean costs per patient were £317 for whole-body MRI (95% CI £273 to £361), versus £620 for standard pathways (95% CI £574 to £666) as fewer other investigations were required.

What does current guidance say on this issue?

NICE guidance published in March 2019 says that people with known or suspected lung cancer should be offered a contrast-enhanced chest CT scan. Other techniques such as ultrasound should be considered if there is doubt. A positron-emission tomography CT should be offered before any potentially curative treatment. It says that MRI should not be routinely used to assess the stage of the primary tumour in non-small-cell lung cancer. In its recommendations for further staging, it says that the presence of metastases should be confirmed by biopsy or further imaging, for example, MRI.

What are the implications?

This study suggests that using whole-body MRI in the initial pathway has similar accuracy for diagnosis, staging and planning treatment of non-small-cell lung cancer.

As clinicians only wanted the results of the positron-emission tomography CT scan for 14% of the WB-MRI group to inform treatment decisions, this means that most people would not need to be exposed to the radiation that CT uses. Fewer investigations and faster staging would be beneficial for both patients and the NHS.

The approach of the study suggests that it reflects how imaging is carried out and interpreted in UK hospitals. Implementation may need some additional training of staff to cope with the number of people who might need whole-body MRI.

Citation and Funding

Taylor S, Mallett S, Ball S et al. Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed non-small-cell lung cancer: the prospective Streamline L trial. Lancet Respir Med. 2019;7:523-32.

This project was funded by the NIHR Health Technology Assessment Programme (project number 10/68/01).

Bibliography

Cancer Research UK. Lung cancer statistics. London: Cancer Research UK; accessed 23 July 2019.

NHS website. Lung cancer. London: Department of Health and Social Care; 2015.

NICE. Lung cancer: diagnosis and management. NG122. London: National Institute for Health and Care Excellence; 2019.

Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed non-small-cell lung cancer: the prospective Streamline L trial

Published on 9 May 2019

S Taylor, S Mallett, S Ball, S Beare, G Bhatnagar, A Bhowmik, P Boavida, J Bridgewater, C Clarke, M Duggan, S Ellis, R Glynne-Jones, V Goh, A Groves, A Hameeduddin, S Janes, E Johnston, D Koh, S Lock, A Miles, S Morris, A Morton, N Navani, A Oliver, T O'Shaughnessy, A Padhani, D Prezzi, S Punwani, L Quinn, H Rafiee, K Reczko, A Rockall, P Russell, H Sidhu, N Strickland, K Tarver, J Teague, S Halligan

The Lancet Respiratory Medicine , 2019

Background Whole-body magnetic resonance imaging (WB-MRI) could be an alternative to multi-modality staging of non-small-cell lung cancer (NSCLC), but its diagnostic accuracy, effect on staging times, number of tests needed, cost, and effect on treatment decisions are unknown. We aimed to prospectively compare the diagnostic accuracy and efficiency of WB-MRI-based staging pathways with standard pathways in NSCLC. Methods The Streamline L trial was a prospective, multicentre trial done in 16 hospitals in England. Eligible patients were 18 years or older, with newly diagnosed NSCLC that was potentially radically treatable on diagnostic chest CT (defined as stage IIIb or less). Exclusion criteria were severe systemic disease, pregnancy, contraindications to MRI, or histologies other than NSCLC. Patients underwent WB-MRI, the result of which was withheld until standard staging investigations were complete and the first treatment decision made. The multidisciplinary team recorded its treatment decision based on standard investigations, then on the WB-MRI staging pathway (WB-MRI plus additional tests generated), and finally on all tests. The primary outcome was difference in per-patient sensitivity for metastases between standard and WB-MRI staging pathways against a consensus reference standard at 12 months, in the per-protocol population. Secondary outcomes were difference in per-patient specificity for metastatic disease detection between standard and WB-MRI staging pathways, differences in treatment decisions, staging efficiency (time taken, test number, and costs) and per-organ sensitivity and specificity for metastases and per-patient agreement for local T and N stage. This trial is registered with the International Standard Randomised Controlled Trial registry, number ISRCTN50436483, and is complete. Findings Between Feb 26, 2013, and Sept 5, 2016, 976 patients were screened for eligibility. 353 patients were recruited, 187 of whom completed the trial; 52 (28%) had metastasis at baseline. Pathway sensitivity was 50% (95% CI 37–63) for WB-MRI and 54% (41–67) for standard pathways, a difference of 4% (−7 to 15, p=0·73). No adverse events related to imaging were reported. Specificity did not differ between WB-MRI (93% [88–96]) and standard pathways (95% [91–98], p=0·45). Agreement with the multidisciplinary team's final treatment decision was 98% for WB-MRI and 99% for the standard pathway. Time to complete staging was shorter for WB-MRI (13 days [12–14]) than for the standard pathway (19 days [17–21]); a 6-day (4–8) difference. The number of tests required was similar WB-MRI (one [1–1]) and standard pathways (one [1–2]). Mean per-patient costs were £317 (273–361) for WBI-MRI and £620 (574–666) for standard pathways. Interpretation WB-MRI staging pathways have similar accuracy to standard pathways, and reduce the staging time and costs. Funding UK National Institute for Health Research.

The majority of people, 97% in the standard pathway of care, had a positron-emission tomography CT scan. Additionally, 13% had a head CT and 9% had a head MRI. Eighteen types of investigations - scans of other areas or biopsies were each conducted in 1% to 6% of patients.

Investigations needed to inform decisions based on whole-body MRI were positron-emission tomography CT in 14% and seven other types of scans or biopsies were each needed in 1% to 3% of patients.

Author commentary

Staging lung cancer using whole-body MRI works just as well as having multiple scans but is quicker, cheaper, preferred by patients and reduces exposure to radiation.

Importantly the research was conducted in a typical NHS setting, so we can be confident that first line whole-body MRI staging would work in the NHS. The next steps are for hospitals to start a whole-body MRI service to build up their experience and to train NHS radiologists to report the scans.

We must ensure patients are aware of the study results so that they can discuss them with their cancer doctors.

Professor Stuart Taylor, Centre for Medical Imaging, University College London