Pulmonary fibrosis in asbestos insulation workers with lung cancer: a radiological and histopathological evaluation

Our plain-English summary of Pulmonary fibrosis in asbestos insulation workers with lung cancer: a radiological and histopathological evaluation, by H.M. Kipen, R. Lilis, Y. Suzuki, et al (British Journal of Industrial Medicine, 1987).

The study

• Authors: H.M. Kipen, R. Lilis, Y. Suzuki, J.A. Valciukas, I.J. Selikoff
• Journal: British Journal of Industrial Medicine
• Published: 1987;44(2):96-100
• Cited by: 110 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. 000328).

Abstract

This study was undertaken to determine the relation between radiographic and histological manifestations of pulmonary asbestosis (interstitial fibrosis) in insulation workers who had died of lung cancer. Of 450 confirmed deaths from lung cancer a chest radiograph suitable for determining evidence of pneumoconiosis was obtained in 219. Of these cases, 138 also had a tissue specimen submitted that was suitable for histological study to determine the extent of histological fibrosis. There was a significant albeit limited correlation between the radiographic and histological findings (r = 0.27, p less than 0.0013). All 138 cases had histological evidence of parenchymal fibrosis; in 25 (18%), however, there was no radiographic evidence of parenchymal fibrosis. In 10 cases (7%) both parenchymal and pleural disease were undetectable on the radiograph. Thus a negative chest radiograph does not exclude the presence of interstitial fibrosis (asbestosis) in a substantial proportion of insulation workers previously exposed to asbestos who develop lung cancer.

In plain English

This study examined members of an insulation workers' union who died of lung cancer between January 1967 and September 1983. It was part of a continuing cohort mortality study of 17,800 union members. Of 450 pathologically confirmed lung cancer deaths, 219 had chest x rays adequate for judging lung scarring, and 138 of these also had enough non-cancerous lung tissue for microscopic grading of fibrosis. All 138 showed diffuse interstitial fibrosis under the microscope, and asbestos bodies were seen in 94% (130/138). Yet in 25 of the 138 (18%) the x ray showed no lung scarring. In 10 (7%) it showed neither lung scarring nor asbestos-related pleural changes, and nine of those ten had moderate or severe fibrosis on microscopy. X ray and microscopic findings showed a significant but limited correlation (r = 0.27, p less than 0.0013). The authors concluded that a negative x ray does not exclude asbestosis. They wrote that the history of asbestos exposure has primacy when considering lung cancer possibly linked to occupational exposure. They stated that their data do not permit conclusions about the causal relation between asbestosis itself and lung cancer.

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 chest x ray readings and lung tissue (histopathology) findings in lung cancer deaths identified within a continuing cohort mortality study
• Who was studied: 138 deceased members of the insulation workers' union (International Association of Heat and Frost Insulators and Asbestos Workers) with pathologically confirmed lung cancer. These were the cases with both an adequate chest x ray and adequate lung tissue, drawn from 219 with adequate x rays out of 450 confirmed lung cancer deaths occurring between January 1967 and September 1983.
• Exposure: Occupational asbestos exposure in insulation work. Fiber types were not specified. The authors cite an estimate that exposures in this group were generally 4-15 fibres per ml.
• Main results:
  • All 138 cases had microscopic (histopathological) evidence of diffuse interstitial fibrosis. The mean degree was 4.7 (SD 1.3), between moderate and severe.
  • Asbestos bodies were seen in 94% of the 138 cases (130/138).
  • 113 of the 138 cases (82%) had radiologically detectable small irregular opacities (ILO profusion 1/0 or greater).
  • In 25 of the 138 cases (18%), interstitial fibrosis was not detectable on the x ray even though it was present on microscopy.
  • 10 of those 25 also had no pleural thickening or plaques on x ray, so 7% of the 138 films showed no asbestos-related changes. Fibrosis on microscopy was moderate or severe in nine of these ten.
  • X ray profusion of small irregular opacities was significantly correlated with the degree of microscopic fibrosis among the 138 cases (r = 0.27, p less than 0.0013).
  • 94 of the 138 cases (68%) had a pleural abnormality on x ray. Its presence or absence was not significantly correlated with x ray profusion of opacities (r = 0.09, p = 0.29) or with microscopic fibrosis (r = 0.12, p = 0.16).
  • Time from onset of asbestos work to death was significantly correlated with x ray profusion of small irregular opacities (r = 0.24, p less than 0.006). It was not significantly correlated with microscopic fibrosis (r = 0.11, p = 0.22).
• The authors' conclusion: The authors concluded that asbestosis was invariably present on histopathology in these insulation workers with lung cancer. X ray and pathology disagreed in 18%, and such disagreement may be more frequent at lower exposures. Including pleural thickening may reduce but not eliminate errors. The findings indicate the primacy of the asbestos exposure history, regardless of x ray changes, when considering lung cancer possibly linked to occupational asbestos exposure.
• Limitations the authors state:
  • The authors state that their data do not permit conclusions about the causal (aetiological) relation between lung cancer and pulmonary asbestosis itself, as distinct from the co-occurrence of lung cancer and asbestos exposure.

Topics

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

Medical terms in this study, explained in our Lexicon: Pulmonary Fibrosis, Insulator, Lung Cancer, Asbestosis, Interstitial Fibrosis, Chest X-Ray, Pneumoconiosis, Fibrosis.

Related studies

• Asbestosis: interstitial pulmonary fibrosis and pleural fibrosis in a cohort of asbestos insulation workers: influence of cigarette smoking — R. Lilis, I.J. Selikoff, et al. (1986)
• Serum type III procollagen peptide: indicator for pulmonary fibrosis: II. Application in 80 asbestos insulation workers — I. Okazaki, K. Maruyama, et al. (1987)
• Pulmonary fibrosis in asbestos insulation workers with lung cancer — Y. Suzuki, H. Kipen, et al. (1987)
• Comparative quantitative evaluation of pleural fibrosis and its effects on pulmonary function in two large asbestos-exposed occupational groups--insulators and sheet metal workers — R. Lilis, A. Miller, et al. (1992)
• Pulmonary fibrosis in asbestos insulation workers with lung cancer — W. Weiss (1989)
• The effect of asbestos-induced pleural fibrosis on pulmonary function: quantitative evaluation — R. Lilis, A. Miller, et al. (1991)

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