Environmental Cancer of the Lung

Our plain-English summary of Environmental Cancer of the Lung, by G.W.H. Schepers (1956).

The study

• Author: G.W.H. Schepers
• Published: American Cancer Society. September 26, 1956
• Type of article: Report
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This is not a published research article. It is a set of American Cancer Society grant papers from the Saranac Laboratory in Saranac Lake, New York, including a progress report dated September 25, 1956. The project tested whether inhaled asbestos dust acted as a co-carcinogen in rats made susceptible to lung cancer by breathing beryllium sulphate. According to the progress report, 116 female Sprague Dawley rats breathed beryllium sulphate aerosol for 6 months. Another 116 breathed asbestos dust at the same time for 6 months. Most were then moved to the other chamber or to normal air, and 51 rats were kept as unexposed controls. An extension application said the Johns-Manville Corporation was supplying chrysotile fiber. Rats killed after 6 months of beryllium sulphate showed early changes (metaplasia) in the lining cells of the air-sac walls. Rats killed after 6 months of asbestos dust did not yet show lesions suggesting tumors. The author wrote that the experiment was proceeding as planned. Exposures were to end on January 5, 1957, and observation was to continue until January 5, 1958.

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: Grant progress report and grant applications describing an ongoing animal inhalation experiment on co-carcinogenesis (beryllium sulphate aerosol combined with asbestos dust in rats); no final results
• Who was studied: Female Sprague Dawley rats at the Saranac Laboratory, Saranac Lake, New York: 116 exposed first to beryllium sulphate, 116 exposed first to asbestos dust, and 51 unexposed controls (progress report of September 25, 1956)
• Exposure: Inhalation of beryllium sulphate aerosol for 6 months and of asbestos dust for 6 months, in either order, followed by normal air. Some rats stayed in their first chamber, and some were killed when they were moved. The extension application states that the asbestos was chrysotile fiber supplied by the Johns-Manville Corporation.
• Main results:
  • Rats exposed to beryllium sulphate for 6 months and then killed showed incipient alveolar wall epithelial metaplasia
  • Rats exposed to asbestos dust for 6 months and then killed did not yet show any suggestive lesions relating to neoplasia
  • In the asbestos-first group, 2 rats died of natural causes
  • In the control group, 12 rats died of natural causes during the first 6 months
  • Exposure phases were scheduled to end on January 5, 1957, with observation and serial sampling continuing until January 5, 1958
• The authors' conclusion: The author drew no conclusion about asbestos and cancer. The author stated only that the experiment was proceeding satisfactorily as planned.
• Limitations the authors state:
  • The author stated that, because the experiment is long-term, an extensive progress report was not yet possible

Topics

Medical terms in this study, explained in our Lexicon: Saranac Laboratory, Lung Cancer, Johns-Manville, Chrysotile.

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