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Published on: October 2, 2015
Asbestos fiber type in malignant mesothelioma: an analytical scanning electron microscopic study of 94 cases
V L Roggli1, P C Pratt, A R Brody
1Durham Veterans Administration, NC.
Abstract:
Although the association between asbestos exposure and malignant mesothelioma is indisputable, controversy continues regarding the relative contribution of the various types of asbestos fibers to the development of mesothelioma. We examined the types of asbestos fibers recovered from lung parenchyma in more than 90 cases of malignant mesothelioma from the United States, using an analytical scanning electron microscope. Almost half of the patients were former asbestos insulators or shipyard workers. The fibers were recovered from lung tissues obtained at autopsy or surgical resection by means of a sodium hypochlorite digestion procedure. Amosite asbestos was identified in 81% of the cases and accounted for 58% of all fibers 5 microns or greater in length. Tremolite/actinolite/anthophyllite were identified in 55% of the cases and accounted for 10% of all fiber types. Chrysotile was identified in 21% of the cases and accounted for 3% of fibers exceeding 5 microns in length. Crocidolite was found in 16% of the cases and accounted for 3% of fibers exceeding 5 microns in length. Nonasbestos mineral fibers (commonly found in the lungs of the general population) were observed in 71% of the cases and accounted for 25% of all fibers 5 microns or greater in length. The findings in this study are at odds with the assertion that crocidolite asbestos is responsible for most mesotheliomas in the United States.
Insights
Amosite asbestos and tremolite were the most common asbestos types found in mesothelioma patients in the U.S. This study challenges the idea that crocidolite asbestos causes most U.S. mesotheliomas.
Area of Science:
- Occupational Health
- Environmental Science
- Pathology
Background:
- The link between asbestos exposure and malignant mesothelioma is well-established.
- Debate persists regarding the specific asbestos fiber types responsible for mesothelioma development.
Purpose of the Study:
- To analyze the types and proportions of asbestos fibers present in lung tissue of U.S. malignant mesothelioma cases.
- To evaluate the contribution of different asbestos fiber types to mesothelioma etiology.
Main Methods:
- Analysis of lung parenchyma from over 90 U.S. malignant mesothelioma patients using analytical scanning electron microscopy.
- Fiber recovery from lung tissues via sodium hypochlorite digestion.
Main Results:
- Amosite asbestos was identified in 81% of cases, comprising 58% of long fibers (>5 microns).
- Tremolite/actinolite/anthophyllite were found in 55% of cases (10% of long fibers).
- Chrysotile (3%) and crocidolite (3%) were less prevalent among long fibers, despite crocidolite being found in 16% of cases.
Conclusions:
- Findings suggest amosite and tremolite are significant contributors to mesothelioma in the U.S.
- The study contradicts claims that crocidolite asbestos is the primary cause of mesothelioma in the United States.
