The lung cancers: staging and response, CT, 18F-FDG PET/CT, MRI, DWI: review and new perspectives

Our plain-English summary of The lung cancers: staging and response, CT, 18F-FDG PET/CT, MRI, DWI: review and new perspectives, by C. Owens, S. Hindocha, R. Lee, et al (The British Journal of Radiology, 2023).

The study

• Authors: C. Owens, S. Hindocha, R. Lee, T. Millard, B. Sharma
• Journal: The British Journal of Radiology
• Published: 2023;96(1148):20220339
• Type of article: Review
• Cited by: 63 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer deaths in both sexes combined. Recent years have seen major advances in the diagnostic and treatment options for patients with non-small-cell lung cancer (NSCLC), including the routine use of 2-deoxy-2[18F]-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in staging and response evaluation, minimally invasive endoscopic biopsy, targeted radiotherapy, minimally invasive surgery, and molecular and immunotherapies. In this review, the central roles of CT and 18F-FDG PET/CT in staging and response in both NSCLC and malignant pleural mesothelioma (MPM) are critically assessed. The Tumour Node Metastases (TNM-8) staging systems for NSCLC and MPM are presented with critical appraisal of the strengths and pitfalls of imaging. Overviews of the Response Evaluation Criteria in Solid Tumours (RECIST 1.1) for NSCLC and the modified RECIST criteria for MPM are provided, together with discussion of the benefits and limitations of these anatomical-based tools. Metabolic response assessment (not evaluated by RECIST 1.1) will be explored. We introduce the Positron Emission Tomography Response Criteria in Solid Tumours (PERCIST 1.0) to include its advantages and challenges. The limitations of both anatomical and metabolic assessment criteria when applied to NSCLC treated with immunotherapy and the important concept of pseudoprogression are addressed with reference to immune RECIST (iRECIST). Separate consideration is given to the diagnosis and follow up of solitary pulmonary nodules with reference to the British Thoracic Society guidelines and Fleischner guidelines and use of the Brock (CT-based) and Herder (addition of 18F-FDG PET/CT) models for assessing malignant potential. We discuss how these models inform decisions by the multidisciplinary team, including referral of suspicious nodules for non-surgical management in patients unsuitable for surgery. We briefly outline current lung screening systems being used in the UK, Europe and North America. Emerging roles for MRI in lung cancer imaging are reviewed. The use of whole-body MRI in diagnosing and staging NSCLC is discussed with reference to the recent multicentre Streamline L trial. The potential use of diffusion-weighted MRI to distinguish tumour from radiotherapy-induced lung toxicity is discussed. We briefly summarise the new PET-CT radiotracers being developed to evaluate specific aspects of cancer biology, other than glucose uptake. Finally, we describe how CT, MRI and 18F-FDG PET/CT are moving from primarily diagnostic tools for lung cancer towards having utility in prognostication and personalised medicine with the agency of artificial intelligence.

In plain English

This was a review, not an original study; it reported no new study results, and its patient images were illustrative examples. The authors reviewed how CT, 18F-FDG PET/CT and MRI are used to stage lung cancer and to judge response to treatment, in non-small cell lung cancer (NSCLC) and in malignant pleural mesothelioma (MPM). They also covered pulmonary nodule guidelines, lung screening and emerging techniques. Asbestos was mentioned only in passing: citing another source, the review stated that MPM is associated with asbestos exposure in 80% of patients. For MPM, the review cited a study reporting that CT had 68% sensitivity and 78% specificity for pleural malignancy but could not reliably tell MPM apart from pleural metastases. It noted that PET/CT can give false-positive results in tuberculous pleurisy or after prior pleurodesis, and stated that thoracoscopic biopsy is required for definitive diagnosis and staging of MPM. It described the modified RECIST method for MPM, which sums six pleural thickness measurements. The authors concluded that the role of imaging will become ever more vital as care moves toward tailored precision medicine.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: narrative review article
• Who was studied: There was no study population. The review covered published work and guidelines on imaging in non-small cell lung cancer and malignant pleural mesothelioma. Individual patients appear only as illustrative image examples in the figures.
• Exposure: Asbestos exposure was not studied. The review was about imaging methods (CT, 18F-FDG PET/CT, MRI, diffusion-weighted MRI). Citing another source, it stated that MPM is associated with asbestos exposure in 80% of patients.
• Main results:
  • Citing another study, the review stated that CT has 68% sensitivity and 78% specificity for pleural malignancy but cannot reliably distinguish MPM from pleural metastatic disease.
  • The review stated that PET/CT cannot distinguish MPM from pleural metastases, and that inflammatory conditions such as tuberculous pleurisy and prior pleurodesis can give false-positive results.
  • The review stated that, whatever imaging is used, thoracoscopic biopsy is required for definitive diagnosis and staging of MPM.
  • The review described the modified RECIST criteria for MPM. Tumour thickness is measured at two positions on three levels of axial CT, and the sum of these six measurements gives a pleural unidimensional measurement.
  • Citing a meta-analysis of 8699 NSCLC patients, the review reported pooled PET/CT sensitivity and specificity of 0.72 and 0.91 for mediastinal nodal staging.
  • Citing the Streamline L trial in newly diagnosed NSCLC, the review reported that whole-body MRI pathways had similar accuracy to standard pathways for T-staging but reduced sensitivity for nodal staging.
• The authors' conclusion: The authors concluded that, as care moves toward tailored precision medicine based on individual tumour and patient characteristics, the role of imaging will become ever more vital.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Staging, Biopsy, Pleural Mesothelioma, Modified RECIST (mRECIST), Immunotherapy, Multidisciplinary Team, Diffusion-Weighted MRI.

Related studies

• Whole-Body MRI: Comparison of Its Capability for TNM Staging of Malignant Pleural Mesothelioma With That of Coregistered PET/MRI, Integrated FDG PET/CT, and Conventional Imaging — Y. Ohno, M. Yui, et al. (2019)
• Loco-regional staging of malignant pleural mesothelioma by integrated 18F-FDG PET/MRI — D.J. Murphy, S.M. Mak, et al. (2019)
• Diagnostic accuracy of sequential co-registered PET+MR in comparison to PET/CT in local thoracic staging of malignant pleural mesothelioma — K. Martini, A. Meier, et al. (2016)
• Positron Emission Tomography/Computed Tomography for the Pleural Staging of Malignant Pleural Mesothelioma: How Accurate Is It? — V. Pinelli, E. Roca, et al. (2015)
• Prognostic value of 18F-FDG standard uptake value by integrated PET/CT in the staging of malignant pleural mesothelioma — G. Genestreti, A. Moretti, et al. (2012)
• High performance of F-fluorodeoxyglucose positron emission tomography and contrast-enhanced CT in a rapid outpatient diagnostic program for patients with suspected lung cancer — P. Brocken, H.F. van der Heijden, et al. (2014)

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