Malignant mesothelioma in British Columbia in 1982

Our plain-English summary of Malignant mesothelioma in British Columbia in 1982, by A. Churg (Cancer, 1985).

The study

• Author: A. Churg
• Journal: Cancer
• Published: 1985;55(3):672-4
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001230).

Abstract

All cases newly diagnosed by a pathologist in 1982 in British Columbia as a malignant mesothelioma of the pleura or peritoneum were reviewed. In men there were 17 cases (incidence rate, 17.0/million/year), and in women 2 cases (1.9/million/year). A history of asbestos exposure (largely in shipyards, construction, or insulation work) was obtained for 14 of 15 men, and 0 of 1 woman. Mineralogic analysis of lung on 6 of the men confirmed that the tumor was associated in every instance with exposure to amosite and crocidolite asbestos; some patients also had elevated levels of tremolite asbestos, presumably reflecting exposure to a chrysotile asbestos product. No unusual levels of asbestos were found in the lungs of the one woman studied. These data show that the incidence rate of mesothelioma in British Columbia has increased nearly six times for men compared to the period 1969 to 1975, but has remained roughly unchanged for women. Almost all of the cases in men in this series could be linked to asbestos exposure.

In plain English

This study reviewed pleural and peritoneal malignant mesothelioma cases newly diagnosed in British Columbia in 1982, found by writing to pathologists (about 95% responded) and checking the tumour registry. After slide review, 5 of 24 cases were excluded. Of the remaining 19, 17 were men and 2 women, giving yearly incidence rates (those older than 15) of 17.0 per million men and 1.9 per million women. Fourteen of the 15 men with an available history had asbestos exposure, mostly in shipyards, construction or insulation trades. In lung tissue from six men, chrysotile was within the general-population range, but amosite and crocidolite were raised about 300-fold on average; two men also had raised noncommercial amphiboles such as tremolite. The one woman tested had no commercial amphibole. Against earlier figures of 3.0 per million men and 1.3 per million women for 1966 to 1975, covering Canadian provinces other than Ontario and Quebec, the author concluded the rate in men had risen about sixfold, with no obvious rise in women. The author cautioned that the counts are probably underestimates and rest on a single year.

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: Province-wide survey of newly diagnosed mesothelioma cases in one calendar year (case series used to calculate incidence). Cases were found by contacting pathologists, about 95% of whom responded, and checked against the provincial tumour registry. Slides were reviewed, occupational histories were taken, and some cases had electron-microscope analysis of asbestos fibers in lung tissue.
• Who was studied: People newly diagnosed with malignant mesothelioma of the pleura or peritoneum in British Columbia in 1982. Of 24 cases initially found, 5 were excluded on slide review (adenocarcinoma, or biopsy too small for diagnosis). That left 19 cases: 17 men and 2 women.
• Exposure: Occupational asbestos exposure in the men, mainly in shipyards (6), construction (4), insulation trades (3) and railroad (1). Lung fiber content was measured for chrysotile, amosite, crocidolite, and noncommercial amphiboles (anthophyllite, actinolite, tremolite).
• Main results:
  • Incidence in 1982 was 17.0 cases per million men older than 15 per year and 1.9 cases per million women over 15 per year.
  • Among men, 15 of 17 tumors were pleural and 2 were peritoneal. Both tumors in women were peritoneal.
  • In the six men whose lungs were analyzed (all with pleural tumors), chrysotile content was within the range of the general population.
  • All six men analyzed had more fibers of the commercial amphiboles (amosite and crocidolite) than an unexposed reference population, on average about 300 times more.
  • Two of the analyzed men (Patients 1 and 2) had increased noncommercial amphiboles such as tremolite. The author suggested these were a marker of past chrysotile exposure.
  • No commercial amphibole was found in the lungs of the one woman analyzed. She had worked as a nurse throughout her career.
  • The comparison rates from earlier studies by McDonald and McDonald (1966 to 1975) were 3.0 per million men and 1.3 per million women. These covered all Canadian provinces except Ontario and Quebec, not British Columbia alone.
  • The article's abstract states that almost all cases in men in this series could be linked to asbestos exposure.
• The authors' conclusion: The author concluded that, compared with 1966 to 1975, the incidence rate in men had increased markedly (about sixfold), with no obvious increase in the rate for women.
• Limitations the authors state:
  • Finding cases by writing to pathologists brings under-reporting and underdiagnosis. This gives an error of unknown size, most likely an underestimate of the true incidence.
  • Incidence was calculated from only one calendar year. The author noted that unreviewed registry data listed 20 cases for 1981.
  • An occupational history could be obtained for only one of the two women.

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, Pleura, Peritoneum, Incidence, Asbestos Exposure, Amosite, Crocidolite, Tremolite.

Related studies

• Identification of occupational cancer risk in British Columbia: a population-based case-control study of 2,998 lung cancers by histopathological subtype — A.C. MacArthur, N.D. Le, et al. (2009)
• Cohort mortality study of pulp and paper mill workers in British Columbia, Canada — P.R. Band, N.D. Le, et al. (1997)
• Surveillance of mesothelioma and workers' compensation in British Columbia, Canada — T.L. Kirkham, M.W. Koehoorn, et al. (2011)
• Identification of occupational cancer risks in British Columbia, Canada: a population-based case-control study of 1,155 cases of colon cancer — R. Fang, N. Le, et al. (2011)
• Acid leaching studies of chrysotile asbestos from mines in the Coalinga region of California and from Quebec and British Columbia — A. Morgan (1997)
• Respiratory health in chrysotile asbestos miners in British Columbia: a longitudinal study — D.A. Enarson, V. Embree, et al. (1988)

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