Lung cancer cell type and asbestos exposure

Our plain-English summary of Lung cancer cell type and asbestos exposure, by A. Churg (JAMA, 1985).

The study

• Author: A. Churg
• Journal: JAMA
• Published: 1985;253(20):2984-5
• Cited by: 36 articles, as counted by NIH iCite
• Read it: PubMed
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000466).

Abstract

It is often claimed that adenocarcinoma is the most frequent type of lung cancer seen in workers exposed to asbestos. Careful review of the published data, however, fails to support this claim. Rather, it seems that all types of lung cancers occur in asbestos workers, and the presence or absence of a specific cell type cannot be used to prove or disprove an association of carcinoma and asbestos exposure.

In plain English

This report was not a new study: the author reviewed published data to test the often-repeated claim that adenocarcinoma is the most common lung cancer type in people exposed to asbestos. Eight reports covered 471 asbestos-exposed patients; three dealt specifically with asbestosis patients. Compared with a Veterans Administration series used as controls, the exposed group overall had fewer adenocarcinomas and more small-cell and squamous carcinomas. In the most-cited report, adenocarcinomas were 35% of lung cancers, but its own comparison data showed no statistical difference from controls. In five series with internal controls, the 410 tumors in exposed workers were 43% squamous, 28% small-cell, 19% adenocarcinoma and 10% large-cell. Adenocarcinoma and large-cell rates did not differ significantly; squamous carcinomas were statistically less frequent and small-cell carcinomas statistically more frequent in the exposed group. The author concluded that all types of lung cancer occur in these workers and that cell type cannot be used to argue for or against asbestos involvement. The author cautioned that pathologists subclassify lung cancers arbitrarily, most series were small, and surgical and autopsy cases were mixed.

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: Brief report reviewing and pooling previously published case series on lung cancer cell type in asbestos-exposed patients (not a new study)
• Who was studied: 471 patients with asbestos exposure from eight published reports; the first three reports dealt specifically with patients with asbestosis, and the others seemed to include some patients with asbestosis. A Veterans Administration lung cancer series served as controls, and a second comparison used five series with internal controls (410 exposed tumors, 1,060 controls).
• Exposure: Asbestos exposure in general, with some or all patients in the series having asbestosis; fiber types are not given
• Main results:
  • Compared with the Veterans Administration control series, the asbestos-exposed group across the eight reports had fewer adenocarcinomas and more small-cell and squamous carcinomas, by the author's observation
  • In the report by Whitwell et al, the one most often cited for a preponderance of adenocarcinoma, adenocarcinomas made up 35% of lung carcinomas in the exposed patients, but using that article's own comparison data there was no statistical difference between exposed and control patients
  • The series of Martischnig et al and of Blot (cited in Ives et al) were heavily skewed toward squamous carcinomas
  • In the five series with internal controls, squamous carcinomas accounted for 43% of the 410 tumors in asbestos-exposed patients
  • In the same 410 exposed tumors, small-cell carcinomas were 28%, adenocarcinomas 19% and large-cell carcinomas 10%
  • There was no significant difference between asbestos-exposed and control patients for adenocarcinomas or large-cell carcinomas
  • Squamous carcinomas were statistically less frequent, and small-cell carcinomas statistically more frequent, in the asbestos-exposed group than in controls
• The authors' conclusion: The author concluded that there is no real evidence for a preponderance of adenocarcinomas in people with asbestos exposure, that all histological types of lung cancer occur in these workers, and that cell type cannot be used as an argument for or against asbestos involvement in a given case
• Limitations the authors state:
  • Uncertainty arises from the arbitrary way pathologists subclassify lung cancers
  • Most of the series are small, so a few changed diagnoses could alter the proportions of tumor types
  • The series mix surgical and autopsy cases, which influences the apparent proportion of cell types
  • The Veterans Administration control group might not be an appropriate match, which is why the author also analyzed series with internal controls

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, Adenocarcinoma, Carcinoma.

Related studies

• A study of the histological cell types of lung cancer in workers suffering from asbestosis in the United Kingdom — F. Whitwell, M.L. Newhouse, et al. (1974)
• Three types of human lung tumour cell lines can be distinguished according to surface expression of endogenous urokinase and their capacity to bind exogenous urokinase — R. Schwartz-Albiez, H.H. Heidtmann, et al. (1992)
• Histologic type of lung cancer and asbestos exposure — O. Auerbach, L. Garfinkel, et al. (1984)
• Incidence of lung cancer by histological type among asbestos cement workers in Denmark — E. Raffn, E. Lynge, et al. (1993)
• Resistance to platinum-based chemotherapy in lung cancer cell lines — J. Chen, N. Emara, et al. (2010)
• Aberrations of chromosome 19 in asbestos-associated lung cancer and in asbestos-induced micronuclei of bronchial epithelial cells in vitro — S.T. Ruosaari, P.E. Nymark, et al. (2008)

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