Criteria For The Diagnosis And Grading Of Asbestosis

Our plain-English summary of Criteria For The Diagnosis And Grading Of Asbestosis, by K.F.W. Hinson, H. Otto, I. Webster, et al (1973).

The study

• Authors: K.F.W. Hinson, H. Otto, I. Webster, C.E. Rossiter
• Published: Biological Effects Of Asbestos (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 8, Pp. 54-57 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 002392. The article is still under copyright, so we describe it here rather than post it.

In plain English

This paper was not a study of patients. Four authors proposed a way to grade lung scarring (pulmonary fibrosis), including asbestosis, in autopsy and lung biopsy material. It extended a scheme from a 1965 working group of the International Union Against Cancer (UICC). The authors proposed recording two things. The first was the extent of lung involvement, judged by looking and touching: A (none), B (less than 25% of the lung), C (25 to 50%) or D (more than 50%). The second was the microscopic severity of fibrosis, graded 0 to 4 by comparison with standard slides. Symbols would note other findings such as pleural plaques, pleural thickening, tumour and tuberculosis. The authors described the grading as purely descriptive and said it does not identify a cause. They proposed that diagnosing asbestosis should require fibrosis containing asbestos bodies or fibres. They made no proposals on which grades should be compensated. They noted that the severity of fibrosis and the number of asbestos bodies are not always proportional, and that other dusts or diffuse fibrosing alveolitis may be hard to tell apart from asbestosis.

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: Proposal for a pathological classification and grading scheme (methods paper); no cases or data were analysed
• Who was studied: No group of people was studied; the scheme is meant for autopsy and lung biopsy material
• Exposure: No exposure was measured. The scheme concerns pulmonary fibrosis in general and asbestosis in particular, with asbestos bodies or fibres in the fibrosis as a diagnostic criterion; no fibre types are named
• Main results:
  • Proposed extent grades judged by inspection and palpation: A none, B less than 25% of the lung, C 25 to 50%, D more than 50%
  • Proposed severity grades 0 to 4 judged microscopically against standard slides. Grade 1 is slight focal fibrosis around respiratory bronchioles with asbestos bodies. Grade 4 is widespread diffuse fibrosis in which few alveoli are recognisable and bronchioles are distorted
  • Symbols were proposed to note other changes: bronchiolectasis, bronchiectasis, tumour, massive fibrosis, pleural plaque, pleural thickening and tuberculosis
  • The authors described the classification as purely descriptive, with no diagnosis of cause, so that it can be compared with respiratory tests and with chest X-rays classified by the ILO system
  • As an example, the authors wrote that fibrosis classified as C3 (grade 3 severity over 25 to 50% of the lung) with numerous asbestos bodies would allow asbestosis to be reasonably diagnosed
  • The authors made no proposals on which grades of fibrosis should be compensatable; they said those decisions belong to national compensation boards and individual pathologists
  • For autopsies, the authors recommended distending at least one lung with fixative before sectioning, and preserving tissue fixed and frozen to show asbestos bodies and fibres in doubtful asbestosis or suspected mesothelioma
• The authors' conclusion: The authors concluded that a necessary criterion for diagnosing asbestosis should be fibrosis with included asbestos bodies or fibres. In their view the grading offers a standard way to assess pulmonary fibrosis so that international and regional comparisons are meaningful, although the diagnosis of asbestosis may still require different decisions in different circumstances
• Limitations the authors state:
  • The authors recognised that grading the extent of fibrosis may be difficult and that the grades will overlap
  • A diffuse chronic pleurisy in people exposed to asbestos, described by Webster (one of the authors), may lead to over-estimation of the extent and severity of asbestosis, particularly when the grade is slight
  • The severity of fibrosis and the number of asbestos bodies are not always proportional
  • Interpretation is harder when asbestosis is associated with long-standing bronchial obstruction, bronchiectasis or chronic infection
  • It may be impossible to distinguish the effects of other fibrogenic dusts inhaled previously or at the same time
  • Telling asbestosis apart from cryptogenic diffuse fibrosing alveolitis may be difficult if occasional asbestos bodies are found in the fibrosis
  • Different countries or situations may require different decisions about which grades indicate asbestosis

Topics

Medical terms in this study, explained in our Lexicon: Pulmonary Fibrosis, Autopsy, Biopsy, UICC, Fibrosis, Pleural Plaques, Pleural Thickening, Asbestos Bodies.

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