The attribution of lung cancers to asbestos exposure: a pathologic study of 924 unselected cases

Our plain-English summary of The attribution of lung cancers to asbestos exposure: a pathologic study of 924 unselected cases, by F. Mollo, C. Magnani, P. Bo, et al (American Journal of Clinical Pathology, 2002).

The study

• Authors: F. Mollo, C. Magnani, P. Bo, P. Burlo, M. Cravello
• Journal: American Journal of Clinical Pathology
• Published: 2002;117(1):90-5
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We studied a series of 924 nonselected surgical cases of lung carcinoma (without occupational history in clinical records) by histologic examination and light microscopic determination of asbestos body (AB) concentration to determine cancers attributable to asbestos exposure. Lower lobes showed higher concentrations, but no significant associations were recorded between concentrations and histologic type of the lung carcinomas. Histologic asbestosis was demonstrated in 56 cases considered definitely asbestos-related. In 12 of them, the demonstration of asbestosis was attained only after repeated examination of additional sections, suggested by thefinding of more than 1,000 ABs per gram of dry weight (gdw), an indicator of occupational asbestos exposure. In the 56 cases, the media

In plain English

This pathology study examined lung tissue from 924 consecutive, unselected patients (806 men, 118 women) operated on for lung carcinoma in Turin, Italy, from December 1992 through December 1998. Their records contained no work histories. The authors counted asbestos bodies in digested lung tissue by light microscopy and examined tissue sections for asbestosis. Men averaged 1,952 asbestos bodies per gram of dry lung tissue (median 188) and women 382 (median 95). Counts above 1,000, which the authors regard as indicating occupational-type exposure, occurred in 106 of 806 men and 10 of 118 women. Asbestosis was found in 56 cases (54 men, 2 women), 12 of them only after extra sections were examined. The authors considered these cancers definitely asbestos-related. Five more cases had interstitial fibrosis and high counts but no asbestos bodies in the sections. Counts did not differ significantly by tumor type. Work histories obtained for 25 cases all confirmed asbestos exposure. The authors estimated that about 6% of the lung cancers were asbestos-related, or about 2,000 cases yearly if extrapolated to Italy. They noted that asbestos bodies form mainly on amphibole fibers, so their estimate may be low.

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: Pathologic study (consecutive case series) of surgically removed lung carcinomas, with asbestos body counts in digested lung tissue and histologic examination for asbestosis
• Who was studied: 924 unselected, consecutive cases of lung carcinoma (806 men, 118 women) examined after pneumonectomy (345) or lobectomy (579) at a university pathology department in Turin, northwestern Italy, December 1992 through December 1998; specimens arrived without occupational histories
• Exposure: Asbestos exposure as indicated by asbestos body concentration (per gram of dry lung tissue), counted by light microscopy after hypochlorite digestion of 'normal' lung tissue, plus histologic asbestosis by CAP and NIOSH criteria; fiber types were not identified
• Main results:
  • Men had higher asbestos body concentrations than women: mean 1,952 per gram of dry weight (median 188) versus 382 (median 95); the difference was statistically significant (P < .001)
  • 116 cases had more than 1,000 asbestos bodies per gram of dry weight: 106 of 806 men (13.2%) and 10 of 118 women (8.5%)
  • Histologic asbestosis was diagnosed in 44 cases at first examination and in 12 more after additional sections were examined in cases with counts above 1,000 per gram of dry weight
  • These 56 cases (54 men, 2 women) were considered definitely asbestos-related; their median asbestos body concentration was 3,281 per gram of dry weight
  • 34 of the asbestosis cases showed only minimal asbestosis (grade 1), 63% of asbestosis cases and 3.7% of the whole series
  • In 5 further cases, all occupationally exposed, interstitial fibrosis and asbestos body counts above the asbestosis median were present, but asbestosis could not be diagnosed because no typical asbestos bodies were seen in the sections
  • 2 cases (both men) with asbestosis had fewer than 1,000 asbestos bodies per gram of dry weight
  • Upper-lobe samples had lower concentrations than lower-lobe samples (P = .02 by Wilcoxon test), but the difference was not significant when only medians were compared
  • Asbestos body concentrations did not differ significantly by histologic type of lung carcinoma
  • Reliable occupational histories were obtained for 25 cases (20 with asbestosis, 5 with interstitial fibrosis and high counts), and all confirmed definite asbestos exposure
  • Adding the 5 fibrosis cases raised the share of definitely or reasonably asbestos-related lung cancers from 6% to 6.6% of the series
  • Extrapolating to Italy's roughly 32,000 lung cancers per year, the authors suggested about 2,000 cases per year should be linked with asbestos. They compared this with 281 lung cancers reported to the national work-injury insurer in 1990-1995 as possibly occupational (from any cause), of which 91 were compensated
• The authors' conclusion: The authors concluded that a thorough pathologic examination, including asbestos body counts, should be performed in all lung carcinomas, even when occupational history is not recorded. They estimated that about 6% of lung cancers were attributable to asbestos, similar to population-based estimates.
• Limitations the authors state:
  • The authors stated that their estimates may be underestimates, which their material could not demonstrate
  • Asbestos bodies form mainly on amphibole fibers, so asbestos body counts may not adequately reflect past exposure, for example to chrysotile

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: Attribution, Lung Cancer, Asbestos Exposure, Carcinoma, Occupational History, Asbestos Body Formation.

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