Diagnostic Value of Computed Tomography Imaging Features in Malignant Pleural Mesothelioma

Our plain-English summary of Diagnostic Value of Computed Tomography Imaging Features in Malignant Pleural Mesothelioma, by M. Fortin, E. Cabon, J. Berbis, et al (Respiration; International Review of Thoracic Diseases, 2020).

The study

• Authors: M. Fortin, E. Cabon, J. Berbis, S. Laroumagne, J. Guinde, X. Elharrar, H. Dutau, P. Astoul
• Journal: Respiration; International Review of Thoracic Diseases
• Published: 2020;99(1):28-34
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Medical history, thoracentesis, and imaging features are usually the first steps in the investigation of a possible malignant pleural effusion (MPE). Unfortunately, the diagnostic yield of thoracentesis in this situation is suboptimal even if the procedure is repeated, especially in the context of malignant pleural mesothelioma (MPM). The next step for confirming the diagnosis, if clinically appropriate, is thoracoscopy, but not all patients are fit to undergo this procedure, so the diagnosis is then based on the medical history and imaging features only.

Objectives: Our objective was to evaluate the diagnostic value of the medical history and imaging features in MPM.

Methods: We reviewed the imaging and medical charts of 92 patients with a final diagnosis of MPE included in our prospective medical thoracoscopy database. The clinical characteristics and imaging features of patients with primary MPE were compared with those of patients with secondary MPE.

Results: Male sex (82 vs. 59%, p = 0.02), asbestos exposure (58 vs. 10%, p < 0.001), and mediastinal (68 vs. 33%, p = 0.04), diaphragmatic (75 vs. 31%, p = 0.001) and circumferential pleural thickening (55 vs. 19% p = 0.001) were significantly more frequent in MPM patients. In a multivariate linear regression model, only asbestos exposure (OR 11.2; 95% CI 3.4-36.9) and circumferential pleural thickening (OR 4.7; 95% CI 1.6-13.9) were significantly associated with a diagnosis of MPM.

Conclusion: In situations where it is impossible to obtain adequate pleural samples to differentiate MPM from a secondary pleural malignancy, the combination of circumferential pleural thickening and a history of asbestos exposure may be sufficient to make a clinical diagnosis.

© 2019 S. Karger AG, Basel.

In plain English

This retrospective study from Marseille, France, asked whether patient history and chest CT features could distinguish malignant pleural mesothelioma from cancer spread to the pleura from another organ (secondary malignant pleural effusion). The authors reviewed records of 92 patients whose pleural cancer was confirmed by biopsy during thoracoscopy between 2012 and 2014. Of these, 40 had mesothelioma and 52 had secondary disease, most often from lung cancer (33) or breast cancer (8). A history of asbestos exposure was recorded in 58% of mesothelioma patients versus 10% of secondary cases. Mediastinal, diaphragmatic and circumferential pleural thickening were more frequent in the mesothelioma group. In a combined model, only asbestos exposure (odds ratio 11.2; 95% confidence interval 3.4 to 36.9) and circumferential pleural thickening (odds ratio 4.7; 95% confidence interval 1.6 to 13.9) were significantly associated with mesothelioma. The authors concluded that when adequate pleural samples cannot be obtained, these two together may be sufficient to make a clinical diagnosis. They noted the small cohort and the CT review by nonradiologists. They also noted that the results may not apply where mesothelioma is less common.

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: Retrospective diagnostic study comparing clinical and chest CT features of malignant pleural mesothelioma with those of secondary (metastatic) malignant pleural effusion, using biopsy diagnosis as the reference standard
• Who was studied: 92 patients with biopsy-confirmed pleural malignancy from a medical thoracoscopy database at North Hospital, Marseille, France, from 2012 to 2014. Of 116 cases identified, 24 were excluded for incomplete data. 40 patients had malignant pleural mesothelioma and 52 had secondary malignant pleural effusion (lung cancer 33, breast cancer 8, other cancers 11).
• Exposure: History of significant occupational asbestos exposure, recorded for 28 of 92 patients (30%). The article does not name fiber types or describe how exposure was assessed. The study also examined chest CT features: costal, mediastinal, diaphragmatic and circumferential pleural thickening, interlobar fissure involvement, pericardial involvement and pleural plaques.
• Main results:
  • Mesothelioma patients were more often male (82% vs 59%, p = 0.02) and more often had asbestos exposure (58% vs 10%, p < 0.001) than patients with secondary malignant pleural effusion.
  • Mediastinal (68% vs 33%), diaphragmatic (75% vs 31%) and circumferential (55% vs 19%) pleural thickening were significantly more frequent in mesothelioma patients than in secondary cases.
  • Costal pleural thickening (67% vs 46%), interlobar fissure thickening (37% vs 23%), pericardial involvement (5% vs 17%) and pleural plaques (15% vs 4%) did not differ significantly between the mesothelioma and secondary groups.
  • In the multivariate model, only asbestos exposure (OR 11.2; 95% CI 3.4 to 36.9) and circumferential pleural thickening (OR 4.7; 95% CI 1.6 to 13.9) were significantly associated with a diagnosis of mesothelioma.
  • The positive likelihood ratio for mesothelioma rose from 2.9 to 7.9 when a patient with circumferential pleural thickening also had a history of asbestos exposure.
  • Circumferential pleural thickening had a sensitivity of 55% (95% CI 38 to 70%) and a specificity of 80% (95% CI 67 to 89%) for mesothelioma.
  • Agreement between the two CT reviewers was rated excellent (kappa 0.83, range 0.70 to 0.96).
• The authors' conclusion: The authors concluded that when adequate pleural samples cannot be obtained to tell mesothelioma from a secondary pleural malignancy, circumferential pleural thickening combined with a history of asbestos exposure may suffice to make a clinical diagnosis.
• Limitations the authors state:
  • CT findings were reviewed retrospectively by nonradiologists, and the cohort was small.
  • The small cohort and the low prevalence of pleural plaques and interlobar fissure involvement may partly explain why those features were not significantly associated with mesothelioma.
  • Mesothelioma made up 43% of the study population, so the results may not apply to populations where mesothelioma is much less common.
  • Lung lesions suspicious for lung cancer or metastasis were not studied, because such patients were sent for biopsy of the lesion rather than for thoracoscopy.
  • The negative predictive values of the imaging features were low, so the absence of these features does not help rule out mesothelioma.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Thoracentesis, Pleural Effusion, Thoracoscopy, Medical Thoracoscopy, Asbestos Exposure, Pleural Thickening.

Related studies

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• Computed tomography features in malignant pleural mesothelioma and other commonly seen pleural diseases — M. Metintas, I. Ucgun, et al. (2002)
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