Problems in the pathology of disease caused by asbestos

Our plain-English summary of Problems in the pathology of disease caused by asbestos, by F. Whitwell (Journal of the Royal Society of Medicine, 1978).

The study

• Author: F. Whitwell
• Journal: Journal of the Royal Society of Medicine
• Published: 1978;71(12):919-22
• Cited by: 8 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. 002160).

Summary of the article

The author, a Liverpool pathologist, discussed the problems of deciding whether disease had been caused by asbestos, at necropsy, for a pneumoconiosis panel, or from old reports and sections. Of 300 suspected mesotheliomas submitted to the Manchester Pneumoconiosis Medical Panel in 1970-1977, the necropsy pathologist's diagnosis was correct in about three-quarters; the commonest error was lung cancer, followed by asbestosis. About 90% of mesotheliomas were thought to have been caused by asbestos. Lung fibre counts in 100 consecutive mesothelioma specimens were compared with 300 control lungs: 75% of controls but 1% of asbestos-induced mesothelioma cases had under 20 000 fibres/g, and 7% of controls but 83% of mesothelioma cases had over 100 000 fibres/g. Seven patients with the lowest counts and no history of exposure were considered spontaneous mesotheliomas. The author concluded that the findings suggested a dose-relationship and did not support the idea that any slight, casual or brief exposure may cause mesothelioma. Among 600 adult necropsies in 1976, pleural plaques were found in 17% of males and 1.6% of females; in the control series, plaques occurred in 55% of patients with over 20 000 fibres/g and 5.5% of those with fewer. Asbestosis was distinguishable from similar fibroses only by asbestos bodies; electron microscopy might be needed where these were absent.

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 pathologist's article discussed how to decide whether disease was caused by asbestos, using panel specimens, lung fibre counts and a necropsy survey. Of 300 suspected mesotheliomas sent to the Manchester Pneumoconiosis Medical Panel in 1970 to 1977, 229 (76.3%) were mesothelioma alone, 3 (1%) mesothelioma with lung cancer and 43 (14.3%) lung cancer. In mesothelioma specimens, asbestos was thought to have caused the tumour in about 90%. Under 20000 fibres per gram were found in 1% of asbestos-induced mesothelioma cases (from 100 consecutive specimens) but 75% of 300 control lungs. Over 100000 fibres per gram were found in 83% of mesothelioma cases and 7% of controls. The author regarded seven low-count patients without asbestos exposure histories as spontaneous cases. Among 600 adult hospital and coroners' necropsies at Broadgreen Hospital in 1976, excluding pneumoconioses, pleural plaques were found in 17% of males and 1.6% of females. The author concluded the findings suggested a dose-relationship and did not support the idea that any slight, casual or brief exposure may lead to mesothelioma. Brief exposure, the author noted, is not the same as slight exposure.

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 discussion by a pathologist, drawing on specimens submitted to a pneumoconiosis panel, lung fibre counts compared with control lungs, and a necropsy survey of pleural plaques
• Who was studied: 300 suspected mesotheliomas submitted by pathologists to the Manchester Pneumoconiosis Medical Panel, 1970 to 1977. Fibre counts were done on 100 consecutive mesothelioma specimens and on 300 control adult lungs from patients without suspected occupational disease. The plaque survey covered 600 adult hospital and coroners' post-mortem examinations at Broadgreen Hospital, Liverpool, in 1976, excluding pneumoconioses.
• Exposure: Asbestos exposure (no fibre type specified), assessed by asbestos bodies in lung sections and smears and by counts of asbestos fibres over 6 micrometres long per gram of lung tissue from the base of a lower lobe
• Main results:
  • Of 300 suspected mesotheliomas, 229 (76.3%) were mesothelioma, 3 (1%) were mesothelioma and lung cancer, 43 (14.3%) were lung cancer, 7 (2.3%) were uncertain tumours, 9 (3%) were asbestosis and 9 (3%) were other diseases. The necropsy pathologist's diagnosis was correct in three-quarters of cases.
  • Among specimens diagnosed as mesothelioma, the tumour was thought to have been caused by asbestos in about 90%. About a quarter of cases showed gross or microscopic asbestosis.
  • In about 40% of mesothelioma cases, only occasional asbestos bodies were found in lung sections or smears.
  • 75% of the 300 controls but only 1% of asbestos-induced mesothelioma cases had under 20000 fibres per gram in the base of a lower lobe.
  • 7% of controls but 83% of mesothelioma cases had over 100000 fibres per gram.
  • Mesothelioma cases with asbestosis nearly always had over 3 million fibres per gram.
  • The seven mesothelioma patients with the lowest counts were 3 housewives, a farmer, a fireman, a clerk and a crankshaft fitter. None had any history of asbestos exposure, and the author regarded them as spontaneous mesotheliomas.
  • Cases with under 1 year's exposure 60 years earlier retained half a million fibres per gram. Cases with 3 months' exposure 30 years earlier retained 250 000 fibres per gram.
  • Among 600 adult post-mortem examinations at Broadgreen Hospital in 1976 (hospital and coroners' cases, excluding pneumoconioses), pleural plaques were found in 17% of males and 1.6% of females.
  • In the control series, pleural plaques were found in 55% of patients with over 20000 fibres per gram, but in only 5.5% of patients with fewer fibres.
• The authors' conclusion: The author concluded that the findings suggest a definite dose-relationship between asbestos inhaled and tumour formation. The author also concluded that they do not support the idea that any slight, casual or brief exposure may lead to mesothelioma. The author noted that brief exposure is not the same as slight exposure.
• Limitations the authors state:
  • The author stated that asbestos bodies form only from fibres over 12 micrometres long, so fibrosis caused by shorter fibres cannot be recognized as asbestosis under the light microscope. Electron microscopy may be needed in such cases.
  • The author stated that no satisfactory explanation was found for pleural plaques in patients with no relevant occupational history and low fibre counts.
  • The author stated that lung collapse and fibrosis on the tumour side often make it impossible to recognize asbestosis there.

Topics

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

Medical terms in this study, explained in our Lexicon: Pathology, Autopsy, Pneumoconiosis, Mesothelioma, Lung Cancer, Pleural Plaques, Asbestos Bodies.

Related studies

• Registry of Diseases Caused by Asbestos. The Importance of Knowing the Scale of the Problem — J. Ferrer Sancho (2020)
• Pulmonary disease caused by the inhalation of cosmetic talcum powder — I.P. Wells, P.A. Dubbins, et al. (1979)
• The pathology of asbestos related disease — J.M. Davis (1984)
• Common problems in asbestos-related pulmonary diseases — A.H. Rubin (1986)
• Awkward medicolegal problems in asbestos-induced disease. Problems in law — C. Clothier (1978)
• Advances in asbestos disease research. Common practical problems: panel discussion — G.L. Baum, S. Gitter, et al. (1986)

Browse more research in Journal of the Royal Society of Medicine, or return to medical research.