Asbestos, asbestosis, and lung cancer: a critical assessment of the epidemiological evidence

Our plain-English summary of Asbestos, asbestosis, and lung cancer: a critical assessment of the epidemiological evidence, by P.A. Hessel, J.F. Gamble, J.C. McDonald (Thorax, 2005).

The study

• Authors: P.A. Hessel, J.F. Gamble, J.C. McDonald
• Journal: Thorax
• Published: 2005;60(5):433-6
• Type of article: Review
• Cited by: 42 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The question of whether lung cancer can be attributed to asbestos exposure in the absence of asbestosis remains controversial. Nine key epidemiological papers are reviewed in a point/counterpoint format, giving the main strengths and limitations of the evidence presented. Of the nine papers, two concluded that asbestosis was necessary and seven that it was not. However, the study design, nature and circumstances of exposure and method of analysis of the studies differed considerably, and none was considered definitive. It is concluded that, because of the relative insensitivity of chest radiography and the uncertain specificity of findings from histological examinations or computed tomography, it is unlikely that epidemiology alone can put either the strict scientific or practical medicolegal questions beyond doubt. It is probable that the issue may depend critically on asbestos fibre type, an aspect not so far addressed.

In plain English

This article was a review, not a new study. The authors examined whether lung cancer can be attributed to asbestos exposure when there is no X-ray evidence of asbestosis, a form of lung fibrosis. They chose nine frequently cited epidemiological papers by agreement among themselves. One author believed X-ray evidence is necessary, one did not, and one was undecided. The papers covered South African amphibole miners, chrysotile miners and millers, Australian crocidolite miners, asbestos cement workers, and hospital patients with lung cancer. For each paper the authors listed strengths and limitations. Two papers concluded that asbestosis was necessary and seven that it was not. However, the studies differed considerably in design, exposure and analysis, and the authors considered none of them definitive. They noted that microscopic examination detects asbestosis far more sensitively than chest X-rays. The authors concluded that epidemiology alone was unlikely to settle either the scientific or the medicolegal question. They also concluded that the answer may depend on asbestos fibre type, which had not so far been addressed. The authors continued to disagree among themselves.

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: review: a point/counterpoint critical assessment of nine published epidemiological papers
• Who was studied: nine frequently cited epidemiological papers, selected by consensus of the three authors, who held differing views on the question
• Exposure: occupational asbestos exposure in the reviewed studies, including South African amphibole miners, chrysotile miners and millers, Australian crocidolite miners, asbestos cement workers, and hospital patients with lung cancer
• Main results:
  • Of the nine papers reviewed, two concluded that asbestosis was necessary for lung cancer to be attributed to asbestos
  • The other seven papers concluded that asbestosis was not necessary
  • The studies differed considerably in design, nature and circumstances of exposure, and method of analysis, and the authors considered none of them definitive
  • The authors noted that microscopic evidence of fibrosis is far more sensitive in detecting asbestosis than chest radiography
  • The authors judged it probable that the issue may depend critically on asbestos fibre type, an aspect not yet addressed
• The authors' conclusion: The authors concluded that, because chest radiography is relatively insensitive and the specificity of findings from histology or CT is uncertain, epidemiology alone is unlikely to put either the strict scientific question or the practical medicolegal question beyond doubt
• Limitations the authors state:
  • For brevity, the descriptions of the reviewed studies were kept minimal
  • Studies of exposure-response between lung cancer and asbestos that did not consider asbestosis were not included
  • Studies in molecular carcinogenesis were not considered, though they may eventually be relevant
  • The approach was meant to inform rather than reach a verdict, and the authors themselves continued to disagree

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, Asbestos Exposure, Epidemiology.

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