Pneumoconiosis And Lung Cancer: With Special Reference To Silicosis And Asbestosis

Our plain-English summary of Pneumoconiosis And Lung Cancer: With Special Reference To Silicosis And Asbestosis, by L.W. Smith (1949).

The study

• Author: L.W. Smith
• Published: Compensation Medicine 2:3-10, November (1949)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002775. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1949 article by a former pathology professor was a narrative review and commentary, not a new study. It reported no data of its own. The author discussed published reports on whether silicosis and asbestosis are linked to lung cancer. The author argued that many reports relied on small series with controls not matched for age and sex. The author held it extremely doubtful that conclusive evidence had shown silicosis caused lung cancer in any single case. The author wrote that more and more evidence appeared to be accumulating to incriminate asbestosis in lung cancer. Among the reports cited, the 1947 Annual Report of the Chief Inspector of Factories in England found pulmonary cancer in 31 of 235 deaths (13.2%) that were caused by asbestosis or showed it at necropsy, from 1924 to 1946. Wedler reported about 15 per cent lung cancer among 92 patients found at autopsy to have asbestosis. The author concluded that the evidence incriminating silicosis as a cause of lung cancer was inadequate, and that such data should be corrected for age and sex.

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 and commentary of published literature (no original data)
• Who was studied: published reports and statistics on silicosis, asbestosis and lung cancer from roughly the preceding 25 years
• Exposure: silica dust (silicosis) and asbestos (asbestosis); no fiber types are named
• Main results:
  • The author argued that Klotz's reported 8 per cent lung cancer rate in 50 autopsied silicosis cases used non-comparable controls. By Klotz's own figures, cancer of all kinds was 18 per cent in the silicosis cases versus 17.7 per cent in unselected controls.
  • Cited from the 1947 Annual Report of the Chief Inspector of Factories (England): among 235 deaths from 1924 to 1946 that were caused by asbestosis or in which asbestosis was found at necropsy, pulmonary cancer was observed in 31 (13.2%). These were 22 of 128 male deaths and 9 of 107 female deaths, with a mean age of 52.1 years.
  • Cited from Wedler: an incidence of approximately 15 per cent of lung cancer in a series of 92 patients found at autopsy to have asbestosis.
  • Cited from Lynch and Smith: two lung cancer cases among 35 autopsy-diagnosed cases of asbestosis over a 12-year period, compared with 0.21 per cent (five cases) in 2308 consecutive autopsies. The author noted that Lynch and Smith urged caution about this comparison.
  • On asbestosis, the author wrote that more and more evidence appeared to be accumulating to incriminate asbestosis as a factor in lung cancer.
  • The author also wrote that it was becoming more difficult to absolve asbestos as a potential factor in lung cancer.
  • On silicosis, the author contended it was extremely doubtful that conclusive evidence had been advanced in any single case that silicosis caused lung cancer.
• The authors' conclusion: The author concluded that the evidence incriminating silicosis as a cause of lung cancer was inadequate, and that such data should be corrected for age and sex.

Topics

Medical terms in this study, explained in our Lexicon: Pneumoconiosis, Lung Cancer, Silicosis, Pathology, Autopsy.

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