Pulmonary cytopathology of former asbestos workers. Report of the first year

Our plain-English summary of Pulmonary cytopathology of former asbestos workers. Report of the first year, by S.D. Greenberg, G.A. Hurst, S.C. Christianson, et al (American Journal of Clinical Pathology, 1976).

The study

• Authors: S.D. Greenberg, G.A. Hurst, S.C. Christianson, W.J. Matlage, I.G. Hurst, L.C. Mabry
• Journal: American Journal of Clinical Pathology
• Published: 1976;66(5):815-22
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001110).

Abstract

Five hundred fifty-four workers, 84% of whom are chronic cigarette smokers, have been examined during the past year with emphasis on the role of sputum cytopathology in the early detection and diagnosis of lung cancer. Of the 554, 232 (42%) have shown squamous metaplasia, 44 (8%), mild to moderate atypias, 18 (3.2%), severe atypias, and two (0.4%), squamous carcinoma. Both of the carcinomas were in x-ray negative, cytopathology-positive elderly cigarette smokers. Ferruginous bodies have been found in the sputa of 187 (33%) workers. Ferruginous bodies in the sputum do not appear to be a marker for severe atypias; rather, their presence correlates best with duration and extent of industrial exposure to asbestos.

In plain English

This first-year report covered screening of former workers from a Tyler, Texas, plant that processed raw South African amosite asbestos from 1954 to 1972. About 2,000 specimens from 554 former workers, 84% smokers, were examined. Sputa showed squamous metaplasia in 232 workers (42%), mild to moderate atypia in 44 (8%), severe atypia in 18 (3.2%) and squamous-cell carcinoma in two (0.4%). Both cancers were in elderly chronic smokers with positive cytology (one man's specimens were tracheal aspirates, after removal of his larynx) but negative chest x-rays; the authors questioned whether these were truly early lesions. Ferruginous bodies were found in 187 workers (33%). They appeared in 15% of sputa from workers employed under six months and 88% from those employed over 15 years. The authors concluded that ferruginous bodies did not appear to mark epithelial atypias but appeared to correlate with exposure duration and extent. They also called sputum cytopathology a simple, inexpensive early-detection method. They noted that the expected peak of lung cancer and mesothelioma, 15 to 30 years after exposure, would not arrive in this cohort until 1983.

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: Screening program report: sputum cytopathology (microscopic examination of coughed-up sputum) in a cohort of former asbestos plant workers, first-year results, with case descriptions of the workers found to have lung cancer
• Who was studied: 554 former workers of the Tyler, Texas, asbestos plant, examined in the first year of the Tyler Asbestos Workers Program. The program cohort was 890 men, 84% of them cigarette smokers. Fifty-three workers had died before the study began and 70 were lost to follow-up. A table footnote mentions 123 controls, who are not otherwise described.
• Exposure: Work at a plant that processed raw amosite asbestos mined in South Africa, 1954 to 1972. Jobs described include guard, sawroom worker, maintenance man, fork-lift operator, warehouse worker, and laborer, builder and supervisor. Employment ranged from six days to 18 years.
• Main results:
  • Of the 554 workers: 232 (42%) showed squamous metaplasia, 44 (8%) mild to moderate atypias, 18 (3.2%) severe atypias, and two (0.4%) squamous carcinoma.
  • Both lung cancers were found by positive cytology with negative chest x-rays. The two men were aged 78 and 74, had smoked 180 and 70 pack-years, and were employed 7 and 10 years. The first man's sputum was positive. He had cancer spread to the pleura at surgery and died six months after hospital discharge. The second man had had a laryngectomy for laryngeal cancer a year earlier. His positive specimens were tracheal aspirates, and he refused further therapy.
  • For the second cancer, the cytology specimens were tracheal aspirates, taken through his permanent tracheal stoma.
  • In the 78-year-old worker, autopsy also showed lung fibrosis with ferruginous bodies and fibrous plaques of the pleura and diaphragm.
  • A 53-year-old worker with an x-ray 'coin lesion' thought to be possible lung cancer had only mild to moderate atypia in sputum. The removed lung lobe contained a granuloma caused by Histoplasma capsulatum, not cancer.
  • Ferruginous bodies were found in the sputa of 187 of the 554 former workers (33%).
  • Among the 187 workers with ferruginous bodies, 72 had them only in aerosol-induced sputum, 27 only in spontaneous sputum, and 88 in both. The authors reported a yield about three times greater in aerosol-induced specimens.
  • Of the 18 workers with severe atypia, 11 had ferruginous bodies in their sputa and 7 did not.
  • Of the 24 workers with moderate numbers and the 36 with many ferruginous bodies, only four had severe atypias or cancer cells in their sputa.
  • Three workers had three or more sputum specimens showing severe atypia. All three were chronic smokers (average age 63, average 65 pack-years) who had worked at the plant six days to one month. None had ferruginous bodies in sputum.
  • Ferruginous bodies were found in 15% of sputa from workers employed less than 6 months and in 88% of sputa from workers employed more than 15 years.
  • In 123 controls, no ferruginous body, moderate to severe atypia, or carcinoma was found. The article does not describe who the controls were.
• The authors' conclusion: The authors concluded that sputum cytopathology is a simple, non-invasive, painless and inexpensive means of early detection of premalignant and malignant lung lesions. They also concluded that ferruginous bodies did not appear to be a marker for epithelial atypias but appeared to serve as a marker for the extent of asbestos exposure.
• Limitations the authors state:
  • The authors questioned whether the two cytology-positive, x-ray-negative cancers in elderly workers were truly early lesions: one had already spread to the pleura, and the other patient could not have surgery.
  • The authors noted that the peak incidence of lung cancer and mesothelioma follows a latency of about 15 to 30 years after exposure. They projected that this critical period would not be reached in these workers until 1983, when their average age would be 55.
  • The report covers only first-year sputum data. Correlations with lung function tests and chest x-rays were planned for the future.

Topics

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

Medical terms in this study, explained in our Lexicon: Cytology, Sputum, Lung Cancer, Carcinoma, Ferruginous body.

Related studies

• Occupational carcinogenesis. High-risk industrial groups: identification, education, and surveillance. Tyler Asbestos Workers Program — S.D. Greenberg, G.A. Hurst, et al. (1976)
• Correlation between respiratory symptoms and pulmonary function in asbestos-exposed workers — C.A. Brodkin, S. Barnhart, et al. (1993)
• Recent advances in pulmonary cytopathology — S.D. Greenberg (1983)
• The clinical significance of ferruginous bodies in sputa — J.W. McLarty, S.D. Greenberg, et al. (1980)
• Cytopathology of asbestos-associated pulmonary disease — S.D. Greenberg (1985)
• Ventilatory decrements in former asbestos cement workers: a four year follow up — C.G. Ohlson, L. Bodin, et al. (1985)

Browse more research in American Journal of Clinical Pathology, or return to medical research.