Quantitative analysis of asbestos burden in a series of individuals with lung cancer and a history of exposure to asbestos

Our plain-English summary of Quantitative analysis of asbestos burden in a series of individuals with lung cancer and a history of exposure to asbestos, by R.F. Dodson, D.R. Brooks, M. O'Sullivan, et al (Inhalation Toxicology, 2004).

The study

• Authors: R.F. Dodson, D.R. Brooks, M. O'Sullivan, S.P. Hammar
• Journal: Inhalation Toxicology
• Published: 2004;16(9):637-47
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestos is recognized as a lung carcinogen. In the present study, tissue from 20 individuals who died from lung cancer and who had a history of exposure to asbestos was evaluated for the presence of asbestos bodies and uncoated asbestos fibers. A digestion procedure was used to isolate the particulates from the tissue. The samples were evaluated by light microcopy to quantify the numbers of ferruginous bodies in the tissue. The uncoated fibers (which included all fibers equal to or greater than 0.5 microm) were analyzed by analytical transmission electron microscopy. Seventeen of the 20 cases were positive for ferruginous bodies (which were morphologically consistent with asbestos bodies). Five of these were found to have concentrations within the range used in our laboratory for the general population (<20 ferruginous bodies/g wet tissue). Nineteen of the 20 cases were found to have asbestos fibers in the higher magnification scan (either 16 K or 20 K). Some of the asbestos fibers identified were specific for the types of exposures that were reported. Most individuals in this study were found to have mixed populations of asbestos fibers in the lung tissue. This suggests that when there are exposures to products containing commercial asbestos there are likely exposures to dust containing noncommercial asbestos. A contrast exists in the dust burden within the lung of these individuals as compared to samples from the general population in that occupational or "occupational-like" exposures such as in these cases are often reflected by the presence of longer fibers of asbestos in the tissue.

In plain English

The authors measured asbestos in the lungs of 20 asbestos-exposed people who died of primary lung cancer. Nineteen men worked in insulation, foundry, marine and other jobs; one woman was exposed through dust on her husband's clothing. Asbestos bodies (coated fibers) were counted by light microscopy, and uncoated fibers 0.5 micrometers or longer by electron microscopy. Seventeen of the 20 had asbestos bodies. The authors wrote that five of these were within their lab's general-population range (20 or less per gram of wet tissue). Their table, however, shows only two of the 17 at that level, plus three cases with none. In the high-magnification scan, 19 cases had uncoated asbestos fibers (3,640 to 32,500,000 per gram of wet tissue); case 2 showed amosite and tremolite only at low magnification. At high magnification, amosite appeared in 15 cases, tremolite 14, crocidolite 12, anthophyllite 11, actinolite 10 and chrysotile 8. The authors noted that the cases, as smokers, were at risk of lung cancer, and that undetected chrysotile does not mean no exposure. They concluded that mixed fiber types were generally found, some matching specific jobs.

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: Case series of lung tissue analyses on discarded autopsy lung tissue. Asbestos bodies were counted by light microscopy and uncoated fibers were identified by analytical transmission electron microscopy. No comparison group was studied, though results were set against the authors' laboratory range for the general population.
• Who was studied: 20 people who died of primary lung cancer and had a history of asbestos exposure: 19 men and 1 woman, who was exposed through dust brought home on her husband's clothing. They were aged 43 to 80, and 17 had a confirmed history of cigarette smoking. Location and time period are not stated.
• Exposure: Occupational asbestos exposure in jobs including insulators, pipe coverers, foundry workers, mechanical maintenance workers and marine-related work, plus one household (domestic bystander) exposure. One case worked at a pipe manufacturing facility where crocidolite and chrysotile were used.
• Main results:
  • 17 of the 20 cases had asbestos bodies on light microscopy, ranging from 20 to 849,647 per gram of wet tissue
  • The authors wrote that in 5 of these 17 cases, asbestos body counts were within their laboratory's range for the general population (20 or less ferruginous bodies per gram of wet tissue)
  • Table 2 does not match that statement. Among the 17 asbestos-body-positive cases, it lists only two at 20 asbestos bodies per gram of wet tissue (cases 11 and 8). It also lists three cases with 0 (cases 5, 9 and 4). Taken together, five of all 20 cases were at 20 or less, not five of the 17 positive cases.
  • Of 193 asbestos bodies analyzed by electron microscopy (from 12 patients), 145 (75.1%) had amosite cores and 32 (16.6%) had crocidolite cores
  • In the quantitative high-magnification scan, uncoated asbestos fibers were found in all cases except case 2. In the positive cases they ranged from 3640 to 32,500,000 per gram of wet tissue. Four cases (16, 17, 6 and 18) had over 1 million asbestos fibers per gram of wet tissue.
  • In case 2, which had no asbestos fibers in the high-magnification scan, the low-magnification scan showed 3 longer fibers (more than 9 micrometers) each of amosite and tremolite
  • In the high-magnification scan, amosite was the most commonly found uncoated fiber type, present in 15 (75%) of the 20 cases
  • Tremolite was found in 14 cases, crocidolite in 12, anthophyllite in 11, actinolite in 10 and chrysotile in 8
  • Case 16 worked in pipe manufacturing, where crocidolite and chrysotile were used. This case had the highest crocidolite concentration (31,783,088 crocidolite fibers per gram of wet tissue), and no chrysotile was detected.
  • Nonasbestos fibers were found in all 20 cases
• The authors' conclusion: The authors concluded that, as in their earlier mesothelioma cases, mixed types of asbestos fibers were generally found in the lung tissue, and that in some cases a specific fiber type could be explained by a specific occupational exposure
• Limitations the authors state:
  • The authors noted that the cases were clearly at risk for lung cancer because they were smokers (17 of 20 had a confirmed smoking history)
  • The authors cautioned that not detecting chrysotile in 60% of the cases should not be read as a lack of chrysotile exposure, because short chrysotile fibers may be cleared from the lung
  • The authors noted that finding no asbestos bodies does not rule out an appreciable burden of uncoated asbestos fibers (as in case 5)

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: Lung Cancer, Asbestos Bodies, Ferruginous Bodies, Analytical Transmission Electron Microscopy (ATEM).

Related studies

• Quantitative analysis of asbestos burden in women with mesothelioma — R.F. Dodson, M. O'Sullivan, et al. (2003)
• Asbestos content of omentum and mesentery in nonoccupationally exposed individuals — R.F. Dodson, M.F. O'Sullivan, et al. (2001)
• Tissue burden evaluation of elongated mineral particles in two individuals with mesothelioma and whose work history included manufacturing tile — R.F. Dodson, L.W. Poye (2020)
• Asbestos burden in cases of mesothelioma from individuals from various regions of the United States — R.F. Dodson, R. Graef, et al. (2005)
• Tissue burden of asbestos in nonoccupationally exposed individuals from east Texas — R.F. Dodson, M.G. Williams, et al. (1999)
• Screening for malignant pleural mesothelioma and lung cancer in individuals with a history of asbestos exposure — H.C. Roberts, D.A. Patsios, et al. (2009)

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