Certified causes of death in patients with mesothelioma in South East England

Our plain-English summary of Certified causes of death in patients with mesothelioma in South East England, by C. Okello, T. Treasure, A.G. Nicholson, et al (BMC Cancer, 2009).

The study

• Authors: C. Okello, T. Treasure, A.G. Nicholson, J. Peto, H. Møller
• Journal: BMC Cancer
• Published: 2009;9:28
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Mesothelioma is a highly fatal cancer that is caused by exposure to asbestos fibres. In many populations, the occurrence of mesothelioma is monitored with the use of mortality data from death certification. We examine certified causes of death of patients who have been diagnosed with mesothelioma, and assess the validity of death certification data as a proxy for mesothelioma incidence.

Methods: We extracted mesothelioma registrations in the South East of England area between 2000 and 2004 from the Thames Cancer Registry database. We retained for analysis 2200 patients who had died at the time of analysis, after having excluded seven dead cases where the causes of death were not known to the cancer registry. The 2200 deaths were classified hierarchically to identify (1) mesothelioma deaths, (2) deaths certified as lung cancer deaths or (3) deaths from unspecified cancer, and (4) deaths from other causes.

Results: 87% of the patients had mesothelioma mentioned on the death certificate. 6% had no mention of mesothelioma but included lung cancer as a cause of death. Another 6% had no mention of mesothelioma or lung cancer, but included an unspecified cancer as a cause of death. Lastly, 2% had other causes of death specified on the death certificate.

Conclusion: This analysis suggests that official mortality data may underestimate the true occurrence of mesothelioma by around 10%.

In plain English

This study checked whether the death certificates of people diagnosed with mesothelioma recorded the disease. The authors linked Thames Cancer Registry records with the recorded causes of death. The records covered 2433 patients (1985 men, 448 women) diagnosed in South East England in 2000–2004. Of the 2207 who had died, the 2200 whose causes of death were known were analysed. Mesothelioma was mentioned on 1905 of the 2200 certificates (87%). Another 128 (6%) listed lung cancer but not mesothelioma; 123 (6%) listed an unspecified cancer but neither of those; the remaining 44 (2%) listed none of these three, only other causes. Mesothelioma was mentioned less often with age: 90% of those up to 69 at diagnosis, 86% at 70 to 79, and 78% at 80 and older. The authors noted that some registered cases could have been misclassified lung cancers or cancers spread from elsewhere. They judged this likely to be small and able to explain only a small part of the lung cancer and unspecified cancer certificates. The authors concluded that official death statistics may undercount mesothelioma by around 10%.

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: Record linkage analysis comparing cancer registry diagnoses of mesothelioma with causes of death on death certificates
• Who was studied: 2433 patients (1985 males, 448 females) diagnosed with mesothelioma in South East England, 2000–2004, from the Thames Cancer Registry. 2207 had died, and 2200 with certified causes of death were analysed. 7 deceased patients with unknown causes of death were excluded.
• Exposure: Not studied; the study examined the causes of death recorded on death certificates, not asbestos exposure.
• Main results:
  • Nationally in England in 2004 there were 1847 registered mesothelioma cases and 1629 mesothelioma deaths, which the authors said suggests crudely that around 88% of cases die from the disease
  • Among the 2200 deceased South East England patients, 1905 (87%) had mesothelioma mentioned on the death certificate
  • 128 of 2200 (6%) had no mention of mesothelioma but lung cancer was mentioned
  • 123 of 2200 (6%) had no mention of mesothelioma or lung cancer but an unspecified cancer was mentioned
  • The remaining 44 of 2200 (2%) had no mention of mesothelioma, lung cancer or unspecified cancer, and had other causes of death on the certificate
  • Mesothelioma was mentioned on the certificate for 90% of patients aged up to 69 at diagnosis, 86% of those aged 70 to 79, and 78% of those aged 80 and older
  • In patients aged 80 and older, 11% were certified as lung cancer deaths and 7% as unspecified cancer deaths
• The authors' conclusion: The authors concluded that official mortality data may underestimate the true occurrence of mesothelioma by around 10%. They considered it most likely that many certificates listing lung cancer or unspecified cancer wrongly omitted mesothelioma.
• Limitations the authors state:
  • The mesothelioma registrations were not verified for the study, so some cases could have been misclassified lung cancers or metastases from other cancers.
  • The authors judged this misclassification likely to be small and able to account for only a small part of the deaths coded as lung cancer or unspecified cancer.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Cancer Registry, Lung Cancer, Death Certificate.

Related studies

• The epidemiology and treatment of mesothelioma in South East England 1985-2002 — V. Mak, E. Davies, et al. (2008)
• Mesothelioma incidence projections in South East England — S.P. Riaz, V.H. Coupland, et al. (2012)
• Malignant mesothelioma in south east England: clinicopathological experience of 272 cases — D.H. Yates, B. Corrin, et al. (1997)
• Use of death certificates in epidemiological studies, including occupational hazards: variations in discordance of different asbestos-associated diseases on best evidence ascertainment — I.J. Selikoff, H. Seidman (1992)
• Estimation of the incidence of pleural mesothelioma according to death certificates in France — Y. Iwatsubo, M. Matrat, et al. (2002)
• Death certificates in epidemiological studies, including occupational hazards: inaccuracies in occupational categories — I.J. Selikoff (1992)

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