Occupational Pulmonary Neoplasms

Our plain-English summary of Occupational Pulmonary Neoplasms, by A. Seaton (1975).

The study

• Author: A. Seaton
• Published: Occupational Lung Diseases (W.K.C. Morgan And A. Seaton, Editors), Philadelphia: W.B. Saunders, Pp. 357-384 (1975)
• Type of article: Book excerpt
• Our copy: from Johns-Manville's own medical library, J-M no. 002831.

In plain English

This textbook chapter was a review of published research on work-related cancers of the lung and pleura. It was not a new study. Its asbestos section described earlier studies. Merewether found that 13.2 per cent of people with asbestosis died of lung cancer, against 1.3 per cent of silicotics. Doll found eleven lung cancer deaths among 113 asbestos textile workers, where 0.8 were expected. Selikoff and co-workers reported that a heavily exposed smoker had a risk of bronchial carcinoma ninety times that of a nonexposed nonsmoker. For mesothelioma, the chapter described Wagner's 1960 report of thirty-three cases in the North West Cape of South Africa. There the geographic pattern pointed to local crocidolite, and the mean time from first exposure was forty years. The author wrote that the evidence showed a greater mesothelioma risk from crocidolite than other forms, some risk from amosite, and little evidence of appreciable risk from chrysotile. Other sections covered radioactive mines, fluorspar, hematite, mustard gas, arsenic, nickel and chromates. The author concluded that the rising hazard was due largely to increasing use of asbestos.

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 chapter in a textbook (Occupational Lung Diseases), summarizing published studies of occupational lung and pleural cancers; no new data collected
• Who was studied: No study population of its own; the chapter reviewed published studies of workers in asbestos, uranium and other mining, fluorspar, hematite, mustard gas, arsenic, nickel, chromate and other industries
• Exposure: Asbestos in general and by fiber type (chrysotile, anthophyllite, crocidolite, amosite), cigarette smoking as a co-factor, and other agents including radioactivity (radon), arsenic, nickel, chromates, mustard gas and coal carbonization products
• Main results:
  • Reported from Merewether's study: 13.2 per cent of subjects with asbestosis died of lung cancer, against 1.3 per cent of silicotics
  • Reported from Doll's study of 113 asbestos textile workers: eleven lung cancer deaths, compared with 0.8 expected
  • Reported from Selikoff and co-workers' study of 632 New York insulation workers: an excess mortality of ninety-nine, due largely to bronchial carcinoma and partly to gastrointestinal neoplasms
  • Reported from Selikoff and co-workers: no bronchial carcinoma in nonsmokers; a heavily exposed smoker had a risk ninety times that of a nonexposed nonsmoker. Berry and co-workers calculated that the effects were almost certainly multiplicative
  • Reported from Wagner and colleagues (1960): thirty-three cases of pleural or peritoneal mesothelioma in the North West Cape of South Africa, linked by geography to crocidolite, not related to dose, with a mean latent period of forty years
  • Reported from Selikoff and co-workers: twenty-two mesotheliomas (six pleural, sixteen peritoneal) among New York insulation workers, about 6 per cent of all deaths, in a trade that used chrysotile and amosite almost exclusively
  • Reported from a Scottish survey: eighty-three mesothelioma cases between 1950 and 1967. 95 per cent gave a history of probable or possible asbestos exposure, against about 35 per cent of cardiovascular disease controls and 65 per cent of lung cancer controls
  • Reported from a Canadian survey of fatal mesothelial tumors, 1959 to 1968: 165 cases. 40 per cent of affected males had a possible or probable history of asbestos exposure, and only one of 50 female patients did
  • In the British mesothelioma register, confirmed new cases rose from seventeen in 1962 to an average of one hundred twenty a year at the time of writing
  • Reported from Timbrell and colleagues: rats exposed to asbestos dust clouds retained six times more amphibole than chrysotile
  • In animal experiments, mesotheliomas were produced as easily by chrysotile as by other fiber types when inoculated into the pleura
  • Reported from Selikoff and co-workers: three times the expected number of insulation workers died of cancer of the stomach and colon
• The authors' conclusion: The author concluded that lung and pleural neoplasms appeared to be an increasing industrial hazard, due largely to the increasing use of asbestos, and that prevention should focus on reducing asbestos exposure and cigarette smoking
• Limitations the authors state:
  • The author noted that further long-term studies in the mining areas were needed to establish that chrysotile and anthophyllite are less dangerous than crocidolite and amosite
  • The author noted that a possible role of adsorbed trace metals and hydrocarbons in mesothelioma had not been proved

Topics

Medical terms in this study, explained in our Lexicon: Neoplasm, Pleura, Lung Cancer, Carcinoma, Mesothelioma, Crocidolite, Amosite, Chrysotile.

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