Asbestos-related cancer risk in patients with asbestosis or pleural plaques

Our plain-English summary of Asbestos-related cancer risk in patients with asbestosis or pleural plaques, by J. Ameille, P. Brochard, M. Letourneux, et al (Revue des Maladies Respiratoires, 2011).

The study

• Authors: J. Ameille, P. Brochard, M. Letourneux, C. Paris, J.C. Pairon
• Journal: Revue des Maladies Respiratoires
• Published: 2011;28(6):e11-7
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: The relationships between benign asbestos-related diseases (asbestosis and pleural plaques) and thoracic cancers are still debated. The aim of this paper was to review the epidemiological data relevant to this issue.

Current Knowledge: Published studies show a significant relationship between occupational exposure to asbestos and lung cancer risk, even in the absence of abnormalities consistent with asbestosis on the postero-anterior chest x-ray. For a given cumulative asbestos exposure, the presence of radiographic evidence of asbestosis is associated with an increased risk of lung cancer. Among asbestos-exposed individuals, those having radiographic evidence of pleural plaques are at increased risk for lung cancer and pleural mesothelioma, compared to the general population. However, there is no evidence that pleural plaque confers an increased risk of lung cancer or pleural mesothelioma within a population of individuals having the same cumulative asbestos exposure.

Perspectives: The studies identified for this review relied only on chest radiograph data. Studies involving accurate evaluations of asbestos exposure and computed tomography of the chest are needed.

Conclusion: Currently available data indicate that patient follow-up modalities should be dictated solely by the estimated cumulative asbestos exposure and not by the existence of pleural plaques.

Copyright © 2011 SPLF. Published by Elsevier Masson SAS. All rights reserved.

In plain English

This was a review of studies on whether X-ray asbestosis or pleural plaques are linked to lung cancer or pleural mesothelioma. Canadian asbestos-cement workers without X-ray asbestosis had 12 lung cancer deaths versus 2.17 expected. A study of former crocidolite miners and residents of Wittenoom, Australia, linked X-ray asbestosis to higher lung cancer risk (RR 1.96; 95% CI 1.09 to 3.46) after adjusting for smoking, age and exposure. People with plaques had more lung cancer and mesothelioma than the general population. Only two studies addressed whether plaques add lung cancer risk at similar exposure; one matched on exposure duration, the other adjusted for duration without reporting cumulative dose. In the Wittenoom data, pleural thickening was not significantly linked to pleural mesothelioma after adjusting for cumulative exposure. The authors concluded there is no proof that, at a given cumulative exposure, plaques are associated with higher lung cancer or pleural mesothelioma risk. In their view, the evidence did not support monitoring people with isolated plaques beyond what their cumulative exposure warrants. They noted the studies used X-rays, not CT, and research was insufficient.

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 of published epidemiological studies (no search method described)
• Who was studied: Published cohort, case-control and autopsy studies of asbestos-exposed groups, which relied on chest radiographs. The total number of studies reviewed is not stated.
• Exposure: Mainly occupational asbestos exposure (in some reviewed studies, residence near mines). Radiographic asbestosis and pleural plaques were examined as markers. Reviewed groups included asbestos-cement, shipyard and construction workers, and crocidolite miners and residents of Wittenoom, Australia.
• Main results:
  • In a reviewed Canadian study of 123 asbestos-cement workers with no radiographic fibrosis, 12 died of lung cancer versus 2.17 expected (SMR 5.5; 95% CI 2.9 to 9.7).
  • In a reviewed 2005 Wittenoom study, after adjustment for smoking, age and asbestos exposure, radiographic asbestosis was associated with increased lung cancer risk (RR 1.96; 95% CI 1.09 to 3.46).
  • An Inserm expert panel pooled six cohort studies. Among individuals with radiographic pleural plaques, 83 died of lung cancer versus 53.9 expected (reported in the text as SMR 1.5; 95% CI 1.2 to 1.9).
  • The authors found only two studies addressing whether pleural plaques raise lung cancer risk among people with similar asbestos exposure. One was a case-control study with cases and controls matched on exposure duration, and it had only 13 cases. The other was CARET. In CARET, plaques or pleural thickening were linked to RR 1.91 (95% CI 1.25 to 2.92) after adjustment for exposure duration, but cumulative asbestos dose was not reported.
  • In a reviewed Swedish cohort of people with pleural plaques, mesothelioma occurred in nine individuals versus 0.8 expected (observed/expected 11.25; 95% CI 5.13 to 21.35).
  • In a reviewed Wittenoom study, after adjustment for time since exposure onset, cumulative exposure and age, radiographic pleural thickening was not significantly associated with pleural mesothelioma. However, pleural plaques were associated with an unexplained increase in peritoneal mesothelioma risk.
• The authors' conclusion: The authors concluded that, for a given cumulative asbestos exposure, there is no proof that pleural plaques are associated with an increased risk of lung or pleural malignancies. They also concluded that the evidence does not support monitoring people with isolated pleural plaques more intensively than the level appropriate to their cumulative asbestos exposure.
• Limitations the authors state:
  • The reviewed studies used chest radiographs instead of CT to detect pleural plaques.
  • The authors stated that the evidence comes from an insufficient amount of research.
  • The available data did not allow evaluation of cancer risk in people with isolated diffuse pleural thickening.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Plaques, Occupational Exposure, Lung Cancer, Chest X-Ray, Asbestos Exposure, Pleural Mesothelioma.

Related studies

• Inter-reader agreement in HRCT detection of pleural plaques and asbestosis in participants with previous occupational exposure to asbestos — F. Laurent, C. Paris, et al. (2014)
• Pleural plaques and the risk of pleural mesothelioma — J.C. Pairon, F. Laurent, et al. (2013)
• Pleural plaques and asbestosis: dose- and time-response relationships based on HRCT data — C. Paris, S. Thierry, et al. (2009)
• Asbestos exposure, pleural plaques, and the risk of death from lung cancer — J.C. Pairon, P. Andujar, et al. (2014)
• Pleural plaques and asbestos: further observations on endemic and other nonoccupational asbestosis — R. Kiviluoto (1965)
• Do asbestos-related pleural plaques on HRCT scans cause restrictive impairment in the absence of pulmonary fibrosis? — B. Clin, C. Paris, et al. (2011)

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