The "missing cases" of pleural malignant mesothelioma in Minnesota, 1979-81: preliminary report

Our plain-English summary of The "missing cases" of pleural malignant mesothelioma in Minnesota, 1979-81: preliminary report, by D.E. Lilienfeld, P.D. Gunderson (Public Health Reports, 1986).

The study

• Authors: D.E. Lilienfeld, P.D. Gunderson
• Journal: Public Health Reports
• Published: 1986;101(4):395-9
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001201).

Abstract

Malignant mesothelioma is a sentinel neoplasm for population exposure to asbestiform fibers. Public health officials may be alerted to temporal or spatial clustering of malignant mesothelioma through analyses of vital records, such as death certificates. Hence, the maintenance of the integrity of the vital statistics system, particularly the cause of death statement on the death certificate, is very important. The report by a northeastern Minnesota radiologist in January 1985 of an elevated prevalence of pleural plaques (related to asbestiform fiber exposure) to the Minnesota Department of Health resulted in an investigation of pleural malignant mesothelioma mortality trends in that area and in three other similar areas in the State. In that study, we noted that in several instances malignant mesothelioma (either intrathoracic or unspecified site) was listed on the death certificate in such a manner as to imply that the neoplasm was either a lung cancer or a malignancy of an unspecified site. The effect of this misclassification is to underestimate the mortality from malignant mesothelioma by fourfold to eightfold. Given the importance of malignant mesothelioma as a proxy for past asbestos exposure, it is necessary to determine the extent of such misclassification for all deaths in the United States.

In plain English

This preliminary report described a review of Minnesota death certificates, begun after a radiologist in Virginia, Minnesota, reported an unusually high prevalence of pleural thickening in January 1985. The authors studied white residents of the northeastern section of the state, where presumed asbestos exposure had occurred, and three comparison sections of about 275,000 people each. The coded death records for 1979 to 1981 listed only one death from pleural malignant mesothelioma, against nine expected based on SEER data. Both authors then reviewed certificates coded as cancers of the respiratory organs or of unspecified site. They found eight deaths from pleural malignant mesothelioma in 1980 to 1981 and none in 1979. Only one of the eight had been coded as a pleural malignancy. Four were coded as lung cancer, two as cancer of unspecified site and one as an unspecified chest malignancy. Because the numbers were small, no statistical tests were done. The authors concluded that this misclassification underestimated deaths from malignant mesothelioma by fourfold to eightfold, and that its extent across the United States should be determined.

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: Preliminary report reviewing coded death records and individual death certificates (descriptive vital statistics study)
• Who was studied: Deaths among white residents of four sections of Minnesota (northeastern, northwestern, southwestern, southeastern), each with a 1980 population of about 275,000. Death certificates reviewed for 1979 to 1981 numbered 405 (1979), 446 (1980) and 474 (1981). Nonwhites were excluded because they made up fewer than 1,000 persons.
• Exposure: No individual exposures were measured and no fiber type was named. Northeastern Minnesota was the area of presumed asbestos exposure, prompted by a radiologist's report of an unusually high prevalence of pleural thickening. The study examined how pleural malignant mesothelioma deaths were coded on death certificates.
• Main results:
  • The initial coded listing for all four areas contained only one death from pleural malignant mesothelioma, compared with nine deaths expected based on SEER data.
  • For comparison, the one observed death from peritoneal malignant mesothelioma was about equal to the 1.6 deaths expected.
  • After the certificates were reviewed, eight deaths from pleural malignant mesothelioma were found in the four areas for 1980 to 1981; none occurred in 1979.
  • Of the eight deaths, only one (a woman in the northeast whose certificate read "Pleural mesothelioma") was coded as a pleural malignancy (ICD-9 163.9). Four were coded as lung cancer (162.9), two as cancer not otherwise stated (199.1), and one as an intrathoracic malignancy not further specified (195.1).
  • In about 25 percent of the cases the certificate did not specify a site at all and simply stated "mesothelioma".
  • Under the standard National Center for Health Statistics coding protocol, a mesothelioma stated to be in the lung is coded as lung cancer, and the fact that it is a mesothelioma is ignored.
  • The misclassification did not vary among the four areas.
• The authors' conclusion: The authors concluded that this misclassification underestimated mortality from malignant mesothelioma by fourfold to eightfold, and that the extent of such misclassification should be determined for all deaths in the United States. They suggested that national officials consider having physicians record intrathoracic malignant mesotheliomas as pleural unless autopsy showed otherwise, or changing the coding convention to account for tumor histology.
• Limitations the authors state:
  • The number of deaths was too small for statistical tests to be performed.
  • Some deaths may have had pleural malignant mesothelioma listed only as a coexisting condition or contributing cause rather than the underlying cause. The authors judged that this could not explain the size of the discrepancy.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Neoplasm, Asbestiform, Death Certificate, Pleural Plaques, Intrathoracic, Lung Cancer, Asbestos Exposure.

Related studies

• Recovering missing mesothelioma deaths in death certificates using hospital records — V.S. Santana, E. Algranti, et al. (2018)
• Peritoneal cancer and occupational exposure to asbestos: results from the application of a job-exposure matrix — P. Cocco, M. Dosemeci (1999)
• Mesothelioma in occupational cohort studies: methodological considerations — N.C. Wojcik, A.R. Schnatter, et al. (2014)
• Missing records in occupational disease epidemiology — P.E. Enterline, G.M. Marsh (1982)
• Primary cardiac tumors: experience at the University of Minnesota — J.E. Molina, J.E. Edwards, et al. (1990)
• Investigating possible effects of abestos in city water: surveillance of gastrointestinal cancer incidence in Duluth, Minnesota — B.S. Levy, E. Sigurdson, et al. (1976)

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