Asbestosis: Vi. Analysis Of Forty Necropsied Cases

Our plain-English summary of Asbestosis: Vi. Analysis Of Forty Necropsied Cases, by K.M. Lynch, W.M. Cannon (1948).

The study

• Authors: K.M. Lynch, W.M. Cannon
• Published: Diseases Of The Chest 14:874-889, November-December (1948)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002856. The article is still under copyright, so we describe it here rather than post it.

In plain English

The authors analyzed forty asbestosis cases found at necropsy (autopsy) at the Medical College of South Carolina over eighteen years. All traced exposure was in an asbestos factory; exposure details were missing from many histories. Cases were grouped by fibrosis grade: 12 minor, 14 medium and 14 advanced. In minor cases an unrelated condition typically caused death, and asbestosis was usually undiagnosed until necropsy. In at least four advanced cases, pulmonary fibrosis played a major part in death. Asbestosis bodies remained in one lung 27 years after exposure ended. Sixteen of the forty had no pleural fibrosis; eight showed nodular fibrosis resembling silicosis. Three of the forty had lung cancer (7.5 per cent), versus 1 per cent in 2,683 general necropsies over ten years. All three had medium to advanced asbestosis. The authors concluded there was evidence the disease did not progress beyond a limited time after exposure ceased, though the fibrosis persisted and aged into dense scar tissue. They wrote that lung cancer was prominent enough to require continued consideration as possibly inducible in a susceptible subject, and that analysis added little weight to a tuberculosis link.

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: Analysis of a series of necropsy (autopsy) cases
• Who was studied: Forty people with asbestosis of some degree found in necropsy studies at the Medical College of South Carolina over eighteen years; 12 minor-grade, 14 medium-grade and 14 advanced-grade cases
• Exposure: Asbestos dust in an asbestos factory where dust control had been progressively improved; duration of exposure was unknown for many cases. The article does not name a fiber type for these cases.
• Main results:
  • Cases were divided by grade of fibrosis: 12 minor, 14 medium, 14 advanced
  • In minor grades, some other unrelated condition characteristically caused death
  • Among the 14 advanced cases, at least four showed pulmonary fibrosis playing a major part in death
  • Twelve cases showed old but not fresh fibrosis
  • The shortest known exposure causing this grade of fibrosis was twenty-eight months, during an elapsed three years
  • Asbestosis bodies remained in the lung at least twenty-seven years
  • Sixteen of the forty cases had no pleural fibrosis, including six advanced cases
  • Eight cases showed nodular fibrosis: five advanced, two medium, one minor grade
  • Lung carcinoma was found in 3 of the 40 asbestosis cases (7.5 per cent), compared with 1 per cent in 2,683 necropsies in the last ten years
  • All three lung carcinoma cases had medium to advanced grades of asbestosis
  • On careful analysis, only four of eight cases with active tuberculosis had active tuberculosis of the lungs
• The authors' conclusion: The authors concluded that the series gave evidence that the disease does not progress beyond a limited time after exposure to asbestos dust ceases, although the fibrosis persists and becomes dense scar tissue. They also concluded that pleural involvement is not constant or essential, and that nodular lesions raise the question whether asbestos can produce them. They wrote that lung carcinoma occurred with such prominence as to require continued consideration as possibly inducible in a susceptible subject, and that the evidence does not add much weight to a link with tuberculosis.
• Limitations the authors state:
  • Information on exposure was missing from many of the histories
  • In one case (49037) the exposure history did not fit the disease state
  • The authors had previously assumed that unknown silica dust exposure was probably involved in the nodular fibrosis

Topics

Medical terms in this study, explained in our Lexicon: Autopsy, Fibrosis, Pulmonary Fibrosis, Silicosis, Lung Cancer.

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