A study of the histological cell types of lung cancer in workers suffering from asbestosis in the United Kingdom

Our plain-English summary of A study of the histological cell types of lung cancer in workers suffering from asbestosis in the United Kingdom, by F. Whitwell, M.L. Newhouse, D.R. Bennett (British Journal of Industrial Medicine, 1974).

The study

• Authors: F. Whitwell, M.L. Newhouse, D.R. Bennett
• Journal: British Journal of Industrial Medicine
• Published: 1974;31(4):298-303
• Cited by: 97 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001292).

Abstract

Whitwell, F., Newhouse, Muriel, L., and Bennett, Diane R. (1974).British Journal of Industrial Medicine,31, 298-303. A study of histological cell types of lung cancer in workers suffering from asbestosis in the United Kingdom. The present study concerns the predominant cell type of lung cancer in workers with certified asbestosis who died of carcinoma of the lung in the United Kingdom between 1962 and 1972. Clinical data, necropsy reports, histological sections, and in some cases paraffin blocks were obtained from the nine pneumoconiosis panels in the country and from hospitals where the patients had been treated. Histological analysis was confined to the 88 male and nine female cases in which adequate postmortem tissue had been obtained. The number of female cases was considered to be too small to be of value as a separate series. Among the males, adenocarcinoma was the commonest type of lung cancer found in 34%. Information about the smoking habits of 69 of the 88 men was obtained; all had smoked at some time. There was little difference between the smoking habits of any group whatever the cell type of carcinoma. The difficulty in finding a comparable series of non-asbestos-exposed individuals is pointed out. It is the usual practice to hold a necropsy on any patient when asbestosis has been certified wherever the place of death. This series therefore has a wider basis of selection than any hospital-based series. Cigarette smoking can exert a carcinogenic effect on different parts of the bronchial tree, producing squamous or oat-celled tumours proximally and adenocarcinoma distally. Asbestos dust lying in distal parts of the lung may exert a co-carcinogenic probably a multiplicative effect with tobacco smoke, producing adenocarcinoma of the distal part of the respiratory tract.

In plain English

This study looked at lung cancer types in United Kingdom workers with asbestosis who died of lung cancer. Cases came from pneumoconiosis panels for 1962 to 1970, from Scotland to the end of 1972, and from a London East End asbestos factory (23 patients, three without certified asbestosis). Of 197 patients listed, material was obtained for 145. The main analysis covered 88 men with adequate postmortem tumour tissue. The type of asbestos fiber was not reported. Adenocarcinoma was the most common type, in 34% of the men. It made up 25% of tumours in men with normal lung or mild asbestosis and 38% in those with moderate or severe asbestosis, a difference that was not statistically significant. Half the adenocarcinomas were described as peripheral, versus 27% of other types. All 69 men with recorded smoking histories had smoked cigarettes; smoking habits differed little by cancer type. The authors suggested that asbestos dust in the outer lung may act with tobacco smoke, probably multiplicatively, to produce adenocarcinoma. They noted that no truly comparable series of non-asbestos lung cancers could be found.

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: Retrospective pathological case series: re-examination of tissue slides and records of deaths from lung cancer among workers with asbestosis. There was no matched control group; an earlier Liverpool hospital series was used for comparison.
• Who was studied: Deaths from lung cancer among workers with asbestosis. Cases came from UK pneumoconiosis panels for 1962 to 1970, plus Scottish cases from 1970 to the end of 1972. They also included 23 patients from a London East End asbestos factory who died of lung cancer, all but three of whom had certified asbestosis. Of 197 patients listed, material was obtained for 145. The histological analysis covered 97 cases with adequate postmortem tissue (88 men, 9 women); the 88 men were analysed.
• Exposure: Occupational asbestos exposure in workers with asbestosis; fiber types and products were not specified. Mean age at first exposure was 28 to 31 years across cell-type groups. All but three men (recorded as exposed for less than two years) had been exposed for more than 10 years.
• Main results:
  • Among the 88 men, adenocarcinoma was the commonest type of lung cancer, found in 34% (30 cases, Table 2).
  • Adenocarcinoma made up 25% of tumours in men with normal lung or mild asbestosis and 38% in men with moderate or severe asbestosis (86 men graded). The difference was not statistically significant.
  • Among 65 men whose lobe of origin was clear, 19 (63%) of the 30 adenocarcinomas and 32 (55%) of the other cell types appeared to arise in a lower lobe.
  • Among 75 men whose tumour could be judged central or peripheral, 15 (50%) of the adenocarcinomas were described as peripheral, compared with 16 (27%) of tumours of other types.
  • Smoking habits were recorded for 69 of the 88 men. All had smoked cigarettes at some time; three had stopped over 20 years before death and eight more recently.
  • Moderate or heavy smokers made up 67% of men with squamous or oat-cell cancers, 64% of men with adenocarcinoma and 76% of men with other cancers. The authors noted that, though the numbers were small, heavier smokers were not more liable to any particular cell type.
  • For comparison, an earlier male Liverpool hospital series (1950 to 1960, no asbestosis found) showed adenocarcinoma in 2% of bronchial biopsy cases, 9.5% of operation cases and 28% of postmortem cases. The authors estimated that adenocarcinoma probably makes up 15 to 20% of lung cancers in an unselected population.
• The authors' conclusion: The authors concluded that cigarette smoking can probably cause cancer in different parts of the bronchial tree. They proposed that asbestos dust reaching the distal parts of the lung may act as a co-carcinogen with tobacco smoke, probably a multiplicative effect, producing adenocarcinoma in the distal respiratory tract.
• Limitations the authors state:
  • The authors stated that finding a comparable series of lung cancers in people not exposed to asbestos seemed insuperable.
  • Lung cancers in early and slight asbestosis may be under-represented. The authors said this means any relationship between cell type and asbestosis is likely to be exaggerated in this series.
  • Not all eligible deaths were included because of administrative errors, missing necropsies, lost records or inadequate sections. The authors judged that these omissions were unlikely to favour any cell type.
  • Smoking information came from old clinical notes, which can be misleading and usually underestimate smoking.
  • The Liverpool comparison cases came from an area where pleural plaques and pleural mesothelioma are relatively common. The authors said that using them as controls may underestimate differences between asbestos-exposed and unexposed groups.
  • The female cases were too few to analyse as a separate series.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Carcinoma, Autopsy, Paraffin Block, Pneumoconiosis, Adenocarcinoma, Habit, Carcinogenic.

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