Malignant mesothelioma not related to asbestos exposure: Analytical scanning electron microscopic analysis of 83 cases and comparison with 442 asbestos-related cases

Our plain-English summary of Malignant mesothelioma not related to asbestos exposure: Analytical scanning electron microscopic analysis of 83 cases and comparison with 442 asbestos-related cases, by A. Kraynie, G.G. de Ridder, T.A. Sporn, et al (Ultrastructural Pathology, 2016).

The study

• Authors: A. Kraynie, G.G. de Ridder, T.A. Sporn, E.N. Pavlisko, V.L. Roggli
• Journal: Ultrastructural Pathology
• Published: 2016;40(3):142-6
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Epidemiological studies indicate that 80-90% of mesotheliomas are asbestos related. This suggests that 10-20% are not. Lung fiber burden analysis provides objective information about past exposures to asbestos. We have performed lung fiber burden analysis on a large cohort of mesothelioma cases and compared the findings with a reference population. Herein we report our findings along with demographic and exposure data.

In plain English

This study, from Duke University Medical Center, analyzed lung tissue from 546 mesothelioma cases in the consultation files of one of the authors. Using light microscopy and scanning electron microscopy, the authors counted asbestos bodies and fibers: the commercial amphiboles amosite and crocidolite, the noncommercial amphiboles tremolite, anthophyllite and actinolite, and chrysotile. They compared the counts with 20 control lungs. In 442 cases at least one measure was clearly above the reference range. In 83 cases all measures were within background, and the authors classed these as non-asbestos-related. A further 21 ambiguous cases were set aside. Women made up 33% (27 of 83) of the non-asbestos-related group and 10% (44 of 442) of the asbestos-related group. Compared with the asbestos-related group, the non-asbestos-related group had a lower mean age (55 versus 66 years), more peritoneal tumors (14% versus 5%), more epithelioid tumors (64% versus 42%) and fewer pleural plaques (7% of 45 informative cases versus 63% of 327). The non-asbestos-related group was 16% of cases that could be classified. The authors concluded that electron microscopy is useful for determining causation in mesothelioma.

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: Laboratory analysis of lung asbestos content in a series of consultation mesothelioma cases, compared with a reference (control) population, with a comparison of cases with and without elevated asbestos content
• Who was studied: 546 mesothelioma cases (506 pleural, 37 peritoneal, 3 of unspecified location) from the consultation files of one author at Duke University Medical Center. They were compared with 20 control cases that had normal lungs at autopsy. Groups analyzed: 442 asbestos-related cases and 83 non-asbestos-related cases. 21 ambiguous cases were excluded.
• Exposure: Asbestos content of the lung measured five ways: asbestos bodies by light microscopy, commercial amphiboles (amosite plus crocidolite), noncommercial amphiboles (tremolite plus actinolite plus anthophyllite), chrysotile fibers, and asbestos bodies by scanning electron microscopy. A case was counted as above background if any one of the five was elevated above the reference range. Only fibers longer than 5 µm were counted.
• Main results:
  • 442 cases had at least one parameter clearly above reference values. 83 cases had all five parameters within the background range. In 15 of those 83 cases, no asbestos bodies or asbestos fibers were found at all.
  • Women were 33% (27 of 83) of the non-asbestos-related group and 10% (44 of 442) of the asbestos-related group (P less than 0.05).
  • Mean age was 66 years (range 31 to 94) in the asbestos-related group and 55 years (range 25 to 84) in the non-asbestos-related group (P less than 0.05).
  • Peritoneal mesothelioma made up 14% (12 of 83) of non-asbestos-related cases and 5% (23 of 442) of asbestos-related cases (P less than 0.05).
  • Sarcomatoid subtype was found in 16% (71 of 442) of asbestos-related cases and 6% (5 of 83) of non-asbestos-related cases. Epithelioid subtype was found in 64% (53 of 83) of non-asbestos-related cases and 42% (184 of 442) of asbestos-related cases. Both differences had P less than 0.05.
  • Asbestosis was found in 9% of the asbestos-related group (37 of 419 informative cases) and in none of the non-asbestos-related group. Pleural plaques were found in 63% of asbestos-related cases (207 of 327 informative) and 7% of non-asbestos-related cases (3 of 45 informative).
  • The share of cases that were asbestos related varied by site and sex: pleural tumors in men 376 of 435 (86%), peritoneal tumors in men 22 of 31 (71%), pleural tumors in women 44 of 71 (62%), and peritoneal tumors in women 1 of 6 (16%).
  • Only 13% (11 of 83) of non-asbestos-related cases came from shipbuilding, US Navy, construction or insulation work, or were pipefitters or boilermakers. These were the leading industries and jobs among asbestos-related cases. Non-asbestos-related cases were mostly household contacts (15 cases), automotive workers (13 cases) and other (14 cases).
  • The non-asbestos-related group made up 16% of cases for which the authors could make a determination of causation based on fiber analysis.
  • Of the 3 non-asbestos-related cases with pleural plaques, the authors judged one likely asbestos related despite the negative fiber analysis. They calculated that in patients with mesothelioma, plaques had a positive predictive value of 99% (207 of 209) for an asbestos cause.
• The authors' conclusion: The authors concluded that non-asbestos-related mesotheliomas were more likely to be in women, in younger patients, in the peritoneum rather than the pleura, and of epithelial subtype. These cases had rare, if any, markers of asbestos exposure. The authors also concluded that electron microscopy is a useful method for determining causation in malignant mesothelioma.
• Limitations the authors state:
  • There were too few cases with asbestosis for asbestosis to work as a significant way of telling the two groups apart.
  • In one case classed as non-asbestos-related, the tissue sample was very limited, so detection limits were high. The authors considered this case likely asbestos related despite the negative fiber analysis.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Asbestos Exposure, Mesothelioma, Fiber Burden Analysis.

Related studies

• Comments on Dodson et al., A technical comparison of evaluating asbestos concentration by phase contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report — V.L. Roggli, T.A. Sporn, et al. (2008)
• Asbestos fiber type in malignant mesothelioma: an analytical scanning electron microscopic study of 94 cases — V.L. Roggli, P.C. Pratt, et al. (1993)
• A technical comparison of evaluating asbestos concentration by phase-contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report — R.F. Dodson, S.P. Hammar, et al. (2008)
• Scanning electron microscopic examination of human asbestos bodies — M.L. Mace, T.L. McLemore, et al. (1980)
• The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study — N.S. Wang, M.C. Jaurand, et al. (1987)
• Pleural mesothelioma in a woman whose documented past exposure to asbestos was from smoking asbestos-containing filtered cigarettes: the comparative value of analytical transmission electron microscopic analysis of lung and lymph-node tissue — R.F. Dodson, S.P. Hammar (2006)

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