Mesothelioma In Relation To Asbestos Fiber Exposure: A Review Of 70 Serial Cases

Our plain-English summary of Mesothelioma In Relation To Asbestos Fiber Exposure: A Review Of 70 Serial Cases, by J.C. Cochrane, I. Webster (1978).

The study

• Authors: J.C. Cochrane, I. Webster
• Published: South African Medical Journal 54(7):279-281, August 12 (1978)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 001070. The article is still under copyright, so we describe it here rather than post it.

In plain English

The authors described 70 consecutive patients with mesothelioma of the pleura referred by Johannesburg thoracic surgeons to the National Research Institute for Occupational Diseases. Diagnoses came from open thoracotomy biopsy, confirmed by the South African Asbestos Tumour Reference Panel. Of the patients, 61 were White and 9 Black. The authors took histories from the patients themselves and repeated every interview at least once. Exposure counted only above set minimums: 4 months of constant exposure to visible floating asbestos fibres, or 4 years in 'room' contact with loose fibre not visible in the air. Environmental cases needed at least 3 years' residence in a mining area, on mine property, or in a town with contact such as childhood play at an asbestos mill or on tailings dumps. Of the 70, 69 had substantive evidence of asbestos contact; one carpenter was recorded as having no significant exposure. Several patients first recorded as unexposed recalled exposure on re-questioning. Intervals from exposure to tumour were 9 to 40 years. The authors concluded that a knowledgeable person must take the history before concluding there was no 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: Case series of consecutive patients, with repeated interviews to take occupational and environmental histories. The article calls it a review of 70 serial cases; it is not a literature review.
• Who was studied: 70 patients with biopsy-confirmed malignant mesothelioma of the pleura, referred by thoracic surgeons of Johannesburg and the Johannesburg General Hospital to the National Research Institute for Occupational Diseases, South Africa. The article describes the period as 4 years. Of the 70, 61 were White and 9 Black. Few were miners.
• Exposure: Occupational and environmental asbestos exposure. Settings included:
• living on asbestos mines in the Northern Cape
• road surfacing with asbestos tailings
• asbestos transport
• mining and milling
• the asbestos-cement industry
• insulation and lagging
• locomotive and ship engine-room work
• building
• electrical work
• asbestos textile handling
• jewellery manufacture

Significant occupational exposure was defined as at least 4 months of constant exposure to an atmosphere of visible floating asbestos fibres, or 4 years in 'room' contact with loose asbestos fibre not visible in the atmosphere.

Environmental cases required at least 3 years' residence in one of these places:

• a mining area
• mine property, where floating fibre was more or less constantly in the air
• a town where, for example, the subject had played in the grounds of an asbestos mill or on dumps of asbestos tailings during childhood

The article does not name fiber types.

• Main results:
  • 69 of the 70 patients had substantive evidence of asbestos contact. For 1 patient, a carpenter, no satisfactory history of asbestos fibre contact could be obtained, and he was recorded as 'no significant exposure'.
  • Some patients first recorded as having no asbestos contact recalled exposure when questioned again. One example was an electrician on the gold mines, recorded as having worked on gold mines only, who recalled cutting and fitting asbestos panels underground.
  • Intervals from exposure to tumour in this series ranged from 9 to 40 years.
• The authors' conclusion: The authors concluded that a knowledgeable person must take an occupational and environmental history before concluding that there has been no asbestos exposure. They stated that they did not suggest that all cases of mesothelioma everywhere in the world are caused by asbestos.
• Limitations the authors state:
  • The series came from Johannesburg referrals. The authors note that Johannesburg draws a considerable share of unusual cases in South Africa, but not all of them.
  • Few Black patients were included because such patients are referred to their regional hospitals, and many refuse further investigation.
  • Few miners were included because the series was based on patients referred from the non-mining industry.
  • Long exposure-to-tumour intervals meant that many patients could not recall their early work history straight away.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Pleura, Occupational Disease, Thoracotomy, Biopsy, Tailings.

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