Morphology of bronchogenic carcinoma in workers formerly exposed to crocidolite at Wittenoom Gorge in Western Australia

Our plain-English summary of Morphology of bronchogenic carcinoma in workers formerly exposed to crocidolite at Wittenoom Gorge in Western Australia, by J.E. Baker, D.C. Reutens, D.F. Graham, et al (International Journal of Cancer, 1986).

The study

• Authors: J.E. Baker, D.C. Reutens, D.F. Graham, G.F. Sterrett, A.W. Musk, M.S. Hobbs, B.K. Armstrong, N.H. de Klerk
• Journal: International Journal of Cancer
• Published: 1986;37(4):547-50
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001188).

Abstract

Cytology and histology material from 46 bronchogenic carcinomas occurring in ex-workers from the Wittenoom crocidolite mine and mill in Western Australia and a matched random sample of 234 other bronchogenic carcinomas occurring in Western Australia over the same period were reviewed by a single histopathologist without knowledge of asbestos exposure status. Squamous-cell carcinomas formed 45.7% of the cancers in the asbestos-exposed group but only 32.5% of the cancers in the comparison group. This difference could not be explained by differences in smoking history between the two groups of lung cancer patients or in the type of histopathological material available for review. The excess of squamous-cell cancers was observed in subjects both with and without parenchymal asbestosis.

In plain English

This study compared lung cancer (bronchogenic carcinoma) cell types in men who had worked at the Wittenoom crocidolite mine and mill in Western Australia with those in other Western Australian men with lung cancer, matched by age and year of diagnosis. There were 91 Wittenoom cases and 369 comparison cases. Of these, 46 and 234 had cell or tissue samples available. One pathologist re-examined the samples without knowing who had been exposed to asbestos. Squamous-cell carcinoma made up 45.7% of the cancers in the Wittenoom group and 32.5% in the comparison group. There were correspondingly fewer adenocarcinomas among the Wittenoom cases (19.6% versus 27.4%). In the statistical analysis, the squamous-cell difference had p = 0.057, and p = 0.051 after allowing for cigarette consumption. Smoking habits and sample types were similar in the two groups. Among Wittenoom men, squamous-cell carcinoma was the most common type with or without a radiological diagnosis of pneumoconiosis. The authors concluded that the study showed an excess proportion of squamous-cell carcinoma in the exposed men, regardless of asbestosis. They noted that smoking and other asbestos exposure were hard to record accurately from past records.

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: Comparison of lung cancer cell types between asbestos-exposed cases and matched comparison lung cancer cases, with blinded review of pathology specimens by a single pathologist and logistic regression analysis
• Who was studied: Men with primary lung cancer who had previously worked in the crocidolite industry at Wittenoom, identified from an ongoing study of past employees. Comparison group: up to 6 male lung cancer patients per case, drawn randomly from all known lung cancer cases in Western Australia from 1958 to 1978 and matched by age and year of diagnosis, excluding those with other known asbestos exposure. Final study population: 91 Wittenoom cases and 369 comparison cases. Of these, 46 Wittenoom cases and 234 comparison cases had adequate pathology specimens for review.
• Exposure: Crocidolite from mining and milling at Wittenoom Gorge, Western Australia; the authors state that most, if not all, workers were exposed only to crocidolite
• Main results:
  • Squamous-cell carcinoma made up 45.7% of the 46 reviewed cancers in the Wittenoom (asbestos-exposed) group and 32.5% of the 234 in the comparison group
  • There was a corresponding deficit of adenocarcinomas among the Wittenoom cases (19.6% versus 27.4% in comparison cases). Other types were similarly distributed, for example small-cell carcinoma at 19.6% versus 19.7%.
  • In logistic regression, the standardized normal deviate for squamous-cell tumours was 1.90 (p = 0.057) with histological types only. It rose to 1.95 (p = 0.051) when cigarette consumption was added.
  • All Wittenoom cases and 98% of comparison cases with smoking data had been smokers. Usual daily cigarette consumption was similar in the two groups, with a median of 20 to 29 cigarettes per day.
  • The two groups were similar in the types of pathology specimens reviewed
  • 20 (43%) of the 46 reviewed Wittenoom workers had a radiological diagnosis of pneumoconiosis. Squamous-cell carcinoma was 45.0% in those with pneumoconiosis and 46.2% in those without. No statistically significant association between pneumoconiosis and cell type was shown, despite an apparent excess of small-cell carcinoma (30.0% versus 11.5%) and deficit of adenocarcinoma (10.0% versus 26.9%) in those with pneumoconiosis.
• The authors' conclusion: The authors concluded that the study showed an excess proportion of squamous-cell carcinoma in the asbestos-exposed (Wittenoom crocidolite) subjects, regardless of the presence or absence of asbestosis
• Limitations the authors state:
  • Data were collected retrospectively, which made accurate recording of smoking habits in both groups, and of other asbestos exposure in the comparison subjects, difficult
  • Data on the amount smoked were missing for 24% of Wittenoom and 21% of comparison subjects
  • The pathologist's blinding was imperfect: histological evidence of asbestosis or asbestos bodies could have revealed exposure status
  • The number of subjects with asbestosis was comparatively small

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Wittenoom, Western Australia

All asbestos mines

Topics

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

Medical terms in this study, explained in our Lexicon: Bronchogenic Carcinoma, Crocidolite, Wittenoom, Cytology, Histology, Asbestos Exposure, Carcinoma, Lung Cancer.

Related studies

• Prevalence of radiographic asbestosis in crocidolite miners and millers at Wittenoom, Western Australia — W.O. Cookson, N.H. De Klerk, et al. (1986)
• Comparison of measures of exposure to asbestos in former crocidolite workers from Wittenoom Gorge, W. Australia — N.H. de Klerk, A.W. Musk, et al. (1996)
• The natural history of asbestosis in former crocidolite workers of Wittenoom Gorge — W. Cookson, N. De Klerk, et al. (1986)
• Retinol supplementation and mesothelioma incidence in workers earlier exposed to blue asbestos (Crocidolite) at Wittenoom, Western Australia — H.S. Alfonso, A. Reid, et al. (2010)
• Malignant pleural and peritoneal mesotheliomas in former miners and millers of crocidolite at Wittenoom, Western Australia — G. Berry, N.H. de Klerk, et al. (2004)
• Malignant mesotheliomas in former miners and millers of crocidolite at Wittenoom (Western Australia) after more than 50 years follow-up — G. Berry, A. Reid, et al. (2012)

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