Occupational lung cancer and smoking: a review in the light of current theories of carcinogenesis

Our plain-English summary of Occupational lung cancer and smoking: a review in the light of current theories of carcinogenesis, by A.C. Chovil (Canadian Medical Association Journal, 1979).

The study

• Author: A.C. Chovil
• Journal: Canadian Medical Association Journal
• Published: 1979;121(5):548-50, 553-5
• Type of article: Review
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002070).

Abstract

This paper considers modern theories of carcinogenesis as they apply to the induction of lung cancer by tobacco smoking and occupational exposure to carcinogens. Some of the known and postulated factors affecting carcinogenesis are discussed, with particular reference to syncarcinogenesis and thresholds. Factors affecting the intensity of smoking exposure are reviewed, and the generally accepted occupational lung carcinogens are listed. Relative risks for the various carcinogens according to smoking status (where known) are presented. The carcinogens are considered individually, and known or postulated interactions with smoking are discussed. It is concluded that the effects of lung carcinogens can be explained on the basis of current theories that support a rational definition of priorities for the prevention of occupational lung cancer.

In plain English

This 1979 article was a review. The author discussed theories of cancer development and how smoking might interact with workplace lung carcinogens: asbestos, arsenic, chlormethyl ethers, chromates, coal tar distillates, mustard gas, radiation and nickel. The author wrote that fairly solid relative risks for smokers and nonsmokers existed only for asbestos workers and uranium miners, with data absent or extremely scanty for the other occupational carcinogens. For asbestos, the evidence reviewed suggested that the risk of bronchogenic carcinoma (lung cancer) was relatively low for a nonsmoker but high for a smoker, and asbestos seemed to involve latent periods of at least 20 years. The author noted that asbestos was nonreactive in the Ames mutagenic test and might act as a foreign body that adsorbs and slowly releases other carcinogens. The author concluded that combined effects might be accounted for by an additive mechanism. While stating that known occupational carcinogens must not be ignored, the author concluded that the most effective immediate step to reduce occupational lung cancer would be concentrating on reducing smoking. The relative-risk table was missing from the supplied text.

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 of theories of carcinogenesis and of published evidence on occupational lung carcinogens and smoking
• Who was studied: No study population of its own; the article reviewed published reports on the generally accepted occupational lung carcinogens
• Exposure: Tobacco smoking and occupational lung carcinogens: asbestos (in mining, refining, insulation work, manufacturing and construction), arsenic, chlormethyl ethers, chromates, coal tar distillates, mustard gas, radiation and nickel
• Main results:
  • According to the author, fairly solid relative risks for smokers and nonsmokers had been established only for asbestos workers and uranium miners
  • For people exposed to asbestos, the evidence reviewed suggested a relatively low lung cancer risk for nonsmokers and a high risk for smokers
  • Asbestos, along with nickel, coal tar distillates and mustard gas, seemed to involve latent periods of at least 20 years
  • The author noted that asbestos is nonreactive in the Ames mutagenic test and suggested it may act as a foreign body in tissue that adsorbs and slowly releases other carcinogens
  • Data on smoking interaction were absent or very scanty for all occupational carcinogens except asbestos and radiation
• The authors' conclusion: The author concluded that combined effects of smoking and occupational carcinogens may be accounted for by an additive mechanism, giving smokers exposed to airborne asbestos or radiation a greatly increased lung cancer risk. The author also concluded that, while known occupational carcinogens must not be ignored, the most effective immediate step to reduce occupational lung cancer would be to concentrate on reducing smoking.
• Limitations the authors state:
  • The author stated that comparing relative risks across studies was very limited because the studies used different designs and control populations and involved large differences in exposure
  • The author stated that the mechanism by which asbestos causes cancer was still obscure

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, Carcinogenesis, Occupational Exposure, Relative Risk.

Related studies

• Occupational cancer of the lung and smoking — (1970)
• Combined effect of asbestos exposure and smoking on mortality from lung cancer in factory workers — G. Berry, M.L. Newhouse, et al. (1972)
• Respiratory carcinogenesis: an epidemiologic appraisal — J.F. Fraumeni (1975)
• Current theories for the development of nonsmoking and nondrinking laryngeal carcinoma — R. Wight, V. Paleri, et al. (2003)
• A case-referent study of lung cancer, occupational exposures and smoking. II. Role of asbestos exposure — H. Kjuus, R. Skjaerven, et al. (1986)
• Interaction between tobacco smoking and occupational exposures in the causation of lung cancer — K. Steenland, M. Thun (1986)

Browse more research in Canadian Medical Association Journal, or return to medical research.