Asbestos and the pleura: a review

Our plain-English summary of Asbestos and the pleura: a review, by D.W. Cugell, D.W. Kamp (Chest, 2004).

The study

• Authors: D.W. Cugell, D.W. Kamp
• Journal: Chest
• Published: 2004;125(3):1103-17
• Type of article: Review
• Cited by: 113 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This review surveyed asbestos-related pleural disease: history and mineralogy, exposure and latency, benign pleural effusions, circumscribed plaques, diffuse pleural thickening, rounded atelectasis, mesothelioma, disease mechanisms and US public policy. The authors noted that US exposure limits fell from 5 fibers per cubic centimeter in 1971 to 0.1 in 1994, and that US asbestos use fell from 803,000 metric tons in 1973 to 16,000 tons in 1998. Even so, pleural abnormalities attributable to asbestos had been increasing. They described the radiologic features of plaques and the pitfalls in detecting them. They summarized conflicting studies on whether plaques impair lung function or raise cancer risk, and stated that the preponderance of the evidence indicated plaques do not increase cancer risk, though this was far from a universal view. They reported general agreement that diffuse pleural thickening can cause significant restrictive ventilatory impairment. For mesothelioma, they reviewed incidence, the greater likelihood of amphibole than chrysotile fibers producing the tumor, the controversial role of simian virus-40, diagnosis, histologic types and poor survival. Mechanisms discussed included reactive oxygen and nitrogen species, DNA damage and p53. The authors stated that low-level exposure in public buildings probably poses no hazard beyond that of breathing outdoor air. They said asbestos-containing materials in buildings should be left in place, covered or sealed, and examined periodically. They also described renewed efforts to base settlement of nonmalignant claims on objective disability assessment.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This article was a narrative review, not an original study. The authors surveyed the history of asbestos, fiber types, clinical and radiologic findings in pleural disease, laboratory research on how asbestos damages cells, and United States public policy. They described four benign pleural reactions (effusions, circumscribed plaques, diffuse pleural thickening and rounded atelectasis) as well as mesothelioma. Citing other studies, they reported that diffuse pleural thickening can cause significant restrictive breathing impairment, that studies of plaques and lung function conflicted, and that most evidence indicated plaques do not increase cancer risk, though this was far from a universal view. They cited mesothelioma rates as high as 366/100,000 person-years in heavily exposed workers versus 67/100,000 in low-to-moderately exposed workers. They also stated that amphibole fibers are much more likely than chrysotile to produce mesothelioma. The authors judged that low-level exposure in public buildings probably adds no hazard beyond breathing outdoor air. They wrote that asbestos materials in buildings should be left in place, covered or sealed, and checked periodically. They noted that a safe exposure level remains controversial.

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 covering history, mineralogy, clinical and radiologic findings, pathogenic mechanisms, and public policy relating to asbestos and the pleura
• Who was studied: No study population of its own. The authors reviewed published literature on asbestos-related pleural disease, drawn mainly from the United States and Europe.
• Exposure: Asbestos in general. The review covers chrysotile (the serpentine form) and the amphiboles: commercial amosite, crocidolite and anthophyllite, and noncommercial tremolite and actinolite. It also covers erionite, a fibrous zeolite. Exposure is grouped as primary (occupational), household, bystander and environmental.
• Main results:
  • The authors described four types of benign pleural reaction to asbestos (effusions, plaques, diffuse pleural fibrosis, rounded atelectasis), in addition to mesothelioma.
  • The authors stated that a pleural effusion can be attributed to asbestos only when there is a history of exposure and other causes, especially malignancy, have been excluded.
  • On circumscribed plaques and lung function, findings conflicted. The cited review by Jones et al concluded that such plaques have no clinically significant effect on lung function; a later review by Rockoff and others reached the opposite conclusion.
  • The authors wrote that most evidence indicates plaques do not increase cancer risk, but that this view is not universal.
  • The authors stated there is general agreement that diffuse pleural thickening, unlike circumscribed plaques, can cause significant restrictive ventilatory impairment.
  • Cited mesothelioma rates were as high as 366/100,000 person-years among heavily exposed workers and 67/100,000 person-years among low-to-moderately exposed workers.
  • The authors stated that exposure to amphibole fibers is much more likely to produce mesothelioma than exposure to chrysotile. They added that mesotheliomas after exposure thought to be limited to chrysotile have been attributed to tremolite contamination.
  • From 10 to 20% of all mesotheliomas are primary in the peritoneum.
  • The causal role of simian virus-40 (SV-40) in mesothelioma was described as controversial.
  • A cited series (Hillerdal) reported survival of 27% of 284 unselected mesothelioma patients at 12 months.
  • The authors stated that low-level exposure in public buildings probably adds no health hazard beyond breathing outdoor air.
• The authors' conclusion: On public policy, the authors' view was that asbestos-containing materials in public buildings and private homes should be left in place, covered or sealed, and examined periodically. They also described renewed efforts to base settlement of nonmalignant asbestos claims on objective criteria such as disability assessment.
• Limitations the authors state:
  • The authors noted that whether a 'safe' exposure level exists remains controversial. They attributed this to difficulty quantifying exposure, variable fiber persistence, differing latency and individual susceptibility.
  • The authors noted that standard chest radiographs miss a substantial proportion of plaques later found at autopsy or by CT, which affects survey results.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Pleura, Asbestos-Related Pleural Disease, Mineralogy, Latency, Pleural Effusion, Diffuse Pleural Thickening, Rounded Atelectasis, Mesothelioma.

Related studies

• Asbestos: when the dust settles an imaging review of asbestos-related disease — H.D. Roach, G.J. Davies, et al. (2002)
• Imaging of the pleura — N.L. Müller (1993)
• Asbestos-induced pleural fibrosis and impaired lung function — D.A. Schwartz, L.J. Fuortes, et al. (1990)
• Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: relationships to interstitial fibrosis (ILO profusion score) and pleural thickening — A. Miller, R. Warshaw, et al. (2013)
• Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type arising in the pleura with pleural fibrous plaques in a lathe worker — S. Nakatsuka, T. Nagano, et al. (2012)
• Asbestos-related diseases of lung and pleura: clinical picture and illustrative cases — B. Varkey, U.N. Kumar (1978)

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