A clinical evaluation and tissue fiber burden analysis of a lifetime resident of Libby, Montana with adenocarcinoma of the lung

Our plain-English summary of A clinical evaluation and tissue fiber burden analysis of a lifetime resident of Libby, Montana with adenocarcinoma of the lung, by R.F. Dodson, B. Black, L.W. Poye, et al (American Journal of Industrial Medicine, 2020).

The study

• Authors: R.F. Dodson, B. Black, L.W. Poye, J.R. Bruce, T. McNew
• Journal: American Journal of Industrial Medicine
• Published: 2020;63(5):456-462
• Type of article: Case report
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Vermiculite mining operations near Libby, Montana were active from the 1920s to 1990. Rail facilities for shipment of the mined material as well as some vermiculite processing activities were ongoing within the community of Libby. A fibrous component within the mined material has been associated with asbestos-related diseases in vermiculite miners and in the local citizens of the community.

Clinical History/methods: We present a clinical case history and tissue fiber burden analysis of an individual with a multifocal adenocarcinoma of the lung who was a lifelong resident of Libby and whose history of exposure was as a member of the general population there.

Results/discussion: To our knowledge this is the first time tissue from a member of the general population of Libby, Montana has been evaluated and shown to contain an appreciable presence of "Libby amphibole" fibers.

© 2020 Wiley Periodicals, Inc.

In plain English

This case report described one woman, a lifelong resident of Libby, Montana, near a vermiculite mine. At age 58 she was diagnosed with multifocal adenocarcinoma (bronchioloalveolar type) of the lung. Neither she nor any immediate family member worked at the mine or its processing facilities. She was reported to be a lifetime nonsmoker but had about 10 years of passive smoke exposure from a parent. The authors examined tumor-free lung tissue by light and electron microscopy. They found no ferruginous bodies (iron-coated fibers). The main electron microscope scan found eight Libby amphibole fibers, calculated as 38 500 fibers per gram of deparaffinized (wax-removed) wet lung tissue. It also found talc fibers (19 250 per gram of the same tissue) and one anthophyllite asbestos fiber. A lower-magnification scan found five more Libby amphibole fibers and one tremolite asbestos bundle. Every Libby amphibole fiber was at least 6 µm long. The authors concluded that this resident had inhaled Libby amphibole fibers, and they called this a unique observation in a person without occupational exposure. They noted that shorter fibers may have been cleared from her lung. The report concerns one person and did not measure disease risk.

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 report: clinical history, pathology review and lung tissue fiber burden analysis of one patient
• Who was studied: One woman, a lifetime resident of Libby, Montana, who worked indoors in public service. At age 58 she was diagnosed with multifocal adenocarcinoma (bronchioloalveolar type) of the right middle and lower lobes. She was reported to be a lifetime nonsmoker with about 10 years of passive cigarette smoke exposure from a parent. None of her immediate family members worked in the mine or affiliated facilities.
• Exposure: Environmental (non-occupational) exposure to Libby amphibole from vermiculite ore. Her family lived in downtown Libby from 1954 to 1976, in areas known for high ambient contamination. Her worksite was six blocks from ore processing facilities. She watched games at ball fields near the railway loading facility (3 hours per day, 5 days per year for 5 years). There was no known or suspected occupational exposure to vermiculite mining or processing. A wood-chip-burning lumber mill powerhouse was reported to be within blocks of the family home.
• Main results:
  • No ferruginous bodies were found by light microscopy in the digested lung tissue. The detection limit was 25 ferruginous bodies per gram deparaffinized wet weight of tissue. None were seen in the tissue sections either.
  • The 15 000× electron microscope scan of the patient's lung digest contained eight Libby amphibole fibers.
  • The Libby amphibole concentration in the patient's lung tissue was calculated as 38 500 fibers per gram deparaffinized wet weight of tissue.
  • The Libby amphibole fibers ranged from 6 to 49 µm in length, and the shortest found in either scan was 6 µm. The average length across both count areas was 17 µm.
  • The 15 000× scan also contained four talc ribbons/fibers, one anthophyllite asbestos fiber and one titanium fiber.
  • Talc fibers/ribbons were the second most common elongated particle, at 19 250 fibers per gram deparaffinized wet weight of tissue.
  • The 2000× scan found five additional Libby amphiboles, four talc fibers/ribbons and one long tremolite asbestos bundle (22 µm long).
  • The authors reported no commercial amphiboles found, within the limit of detection, in either scan. The article does not list which fiber types it counts as commercial amphiboles.
  • Lung tissue with only minimal carcinoma showed no significant respiratory bronchiolar or alveolar septal fibrosis. Black pigmented deposits were seen in bronchioles and lymph nodes.
• The authors' conclusion: The authors concluded that this member of Libby's general population had inhaled Libby amphibole fibers, and that the fibers remaining in her lung were all long (over 5 µm). They described this as a unique observation in a non-occupationally exposed patient with lung cancer. They noted that their laboratories had never found Libby amphibole in their studies of general populations.
• Limitations the authors state:
  • The lower-magnification (2000×) scan may miss short or thin fibers.
  • The absence of Libby amphibole fibers shorter than 5 µm may reflect clearance of smaller fibers from the lung by the time the tissue was sampled.
  • Details of the patient's passive smoking exposure were not available.
  • Other lung carcinogens, such as PAHs from the nearby wood-burning facility, may have been emitted, but no longitudinal PAH monitoring was done in Libby.

Topics

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

Medical terms in this study, explained in our Lexicon: Fiber Burden Analysis, Adenocarcinoma, vermiculite, Libby amphiboles.

Related studies

• A clinical assessment and lung tissue burden from an individual who worked as a Libby vermiculite miner — B. Black, R.F. Dodson, et al. (2017)
• Select mortality and cancer incidence among residents in various U.S. communities that received asbestos-contaminated vermiculite ore from Libby, Montana — D.K. Horton, F. Bove, et al. (2008)
• Exposure to asbestos-containing vermiculite ore and respiratory symptoms among individuals who were children while the mine was active in Libby, Montana — L.C. Vinikoor, T.C. Larson, et al. (2010)
• A review of the federal government's health activities in response to asbestos-contaminated ore found in Libby, Montana — K. Horton, V. Kapil, et al. (2006)
• Potency factors for risk assessment at Libby, Montana — S.H. Moolgavkar, J. Turim, et al. (2010)
• Vermiculite, respiratory disease, and asbestos exposure in Libby, Montana: update of a cohort mortality study — P.A. Sullivan (2007)

Browse more research in American Journal of Industrial Medicine, or return to medical research.