Practical steps towards the prevention of bronchial carcinoma

Our plain-English summary of Practical steps towards the prevention of bronchial carcinoma, by R. Doll (Scottish Medical Journal, 1970).

The study

• Author: R. Doll
• Journal: Scottish Medical Journal
• Published: 1970;15(12):433-47
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this lecture, the author reviewed the agents known to cause bronchial carcinoma and discussed practical steps to reduce the risk. The agents considered were chrome ore, nickel ore, mustard gas, arsenic, asbestos, coal tar, ionizing radiations and cigarette smoke. Three studies of heavily exposed asbestos workers, two in England and one in the United States, had found grossly increased lung cancer mortality, for example 27 observed against 2.3 expected deaths in insulation workers. Mesothelioma had occurred after minimal exposure. Among Londoners aged 60 to 79, the proportion of autopsy lung samples showing asbestos bodies rose from 0 per cent in 1936 to 20 per cent in 1966. Among British doctors, lung cancer incidence rose from about 8 per 100,000 men per year in non-smokers to 350 in men smoking 35 or more cigarettes a day. Smoking was estimated to account for about 88% of cases in male doctors aged 35 to 84. Data on asbestos insulation workers and uranium miners fitted a multiplicative, rather than additive, effect of smoking combined with the occupational agent. The author concluded that prevention lay primarily in reducing cigarette smoking. He proposed banning general tobacco advertising except at the point of sale, and a tax differential favouring pipes and cigars. For asbestos, he recommended discouraging crocidolite use, licensing its import, labelling domestic products, sealing exposed asbestos and disposing of waste safely.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This article is the text of a 1970 lecture by the author. It is a review, not a new study. It summarized published evidence on agents identified as causes of bronchial carcinoma, including asbestos, ionizing radiation and cigarette smoke, and discussed prevention. On asbestos, it described three studies of heavily exposed workers, two in England and one of insulation workers in the United States. All three showed greatly increased deaths from lung cancer and other respiratory disease. It also cited a review of autopsy material that found many mesotheliomas not reported on death certificates. In one factory study, mesotheliomas occurred in men exposed for less than 1 to 9 years. In a London series of people aged 60 to 79, the share of lung tissue samples showing asbestos bodies rose from 0 per cent in 1936 to 20 per cent in 1966. Data on insulation workers fitted a multiplying combination of asbestos and smoking better than an adding one. The author concluded there could be no serious doubt that asbestos can cause bronchial carcinoma, while stating that the exposure needed was uncertain. The author argued that prevention lies primarily in reducing cigarette smoking and that crocidolite use should be discouraged.

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 delivered as a lecture (the Thorn Bequest Lecture), summarizing published evidence on causes and prevention of bronchial carcinoma
• Who was studied: No new study population. For asbestos, the lecture drew on three published studies of heavily exposed workers: two asbestos factory groups in England and asbestos insulation workers in the United States. It also drew on other cited reports.
• Exposure: Agents identified as causes of bronchial carcinoma: chrome ore, nickel ore and nickel refining, mustard gas, arsenic, asbestos, coal tar, ionizing radiations and cigarette smoke. For asbestos, heavy occupational exposure was discussed, with crocidolite (blue asbestos) singled out for mesothelioma.
• Main results:
  • In the three cited studies of heavily exposed asbestos workers, all three groups had greatly increased deaths from lung cancer and from other respiratory disease. Two of the three groups had a considerable increase in deaths from other cancers.
  • In the cited review of autopsy reports and tissue slides from one factory (Newhouse and Wagner, 1969), a large number of mesotheliomas were found that had not been reported on death certificates.
  • In the asbestos textile factory study (Knox et al., 1968), one mesothelioma was recognised among 23 lung cancers in heavily exposed men employed at least 20 years.
  • In the same factory study, four other mesotheliomas occurred in men directly exposed for periods of less than 1 to 9 years.
  • Three of these four men were not considered to have asbestosis at autopsy. Their latent periods from first exposure to death were 40, 42 and 57 years.
  • In cited observations on autopsy lung tissue held at a London hospital laboratory (Pooley et al., 1969), the proportion of persons aged 60 to 79 showing asbestos bodies rose from 0 per cent in 1936, to 3 per cent in 1946, 11 per cent in 1956 and 20 per cent in 1966.
  • In 1968, the first year the Registrar General separated pleural mesothelioma from other lung cancers, 120 deaths were attributed to the disease.
  • Among the cited asbestos insulation workers (Selikoff et al., 1968), the risk of bronchial carcinoma was about eight times the normal national risk.
  • Smoking histories from these insulation workers fitted a multiplying effect of asbestos and smoking better than an adding effect. The author noted that the data were still few.
  • The author concluded that asbestos can cause bronchial carcinoma. The author suggested that the apparent excess of other cancers may reflect pleural and peritoneal mesotheliomas misdiagnosed as other cancers.
  • The author recommended discouraging the use of crocidolite whenever possible.
• The authors' conclusion: The author concluded that the opportunity for preventing bronchial carcinoma lies primarily in reducing smoking, particularly cigarette smoking.
• Limitations the authors state:
  • How much asbestos exposure is needed to produce cancer is uncertain.
  • Evidence of increased bronchial carcinoma deaths came only from heavily exposed groups. A small occupational risk is hard to detect against the high general risk.
  • The Newhouse and Wagner results may not be typical of asbestos workers generally, because crocidolite had been used extensively in that factory.
  • The rise in diagnosed mesothelioma may reflect greater awareness among doctors rather than a real increase.

Topics

Medical terms in this study, explained in our Lexicon: Carcinoma, Lung Cancer, Insulator, Mesothelioma, Autopsy, Asbestos Bodies, Crocidolite.

Related studies

• Cohort analysis of changes in incidence of bronchial carcinoma in a textile asbestos factory — J.F. Knox, R.S. Doll, et al. (1965)
• Biomarker assessments in asbestos-exposed workers as indicators for selective prevention of mesothelioma or bronchogenic carcinoma: rationale and practical implementations — E. Pluygers, P. Baldewyns, et al. (1992)
• Biomarker assessments in asbestos-exposed workers as indicators for selective prevention of mesothelioma or bronchogenic carcinoma: rationale and practical implementations — E. Pluygers, P. Baldewyns, et al. (1991)
• Smoking status, occupational asbestos exposure and bronchial location of lung cancer — C. Paris, J. Benichou, et al. (2003)
• Smoking, occupational risk factors, and bronchial tumor location: a possible impact for lung cancer computed tomography scan screening — M. Gonzalez, J.M. Vignaud, et al. (2012)
• The relationship between asbestosis and bronchial cancer — G.K. Sluis-Cremer (1980)

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