Assessing the completeness and correctness of the registration of malignant mesothelioma in Belgium

Our plain-English summary of Assessing the completeness and correctness of the registration of malignant mesothelioma in Belgium, by M. Rosskamp, H. De Schutter, K. Henau, et al (Lung Cancer, 2018).

The study

• Authors: M. Rosskamp, H. De Schutter, K. Henau, K. Nackaerts, J.P. Van Meerbeeck, M. Praet, L. Van Eycken
• Journal: Lung Cancer
• Published: 2018;122:38-43
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Malignant mesothelioma (MM) is a rare and aggressive cancer mostly caused by asbestos exposure, and for which the diagnosis is difficult. This study aimed to assess the completeness and correctness of MM registration using 3 independent national databases: the Belgian Cancer Registry (BCR), the population-based mortality statistics (certificates of death, COD), and the Belgian Mesothelioma Registry (BMR).

Methods: The study cohort included all MM reported to the BCR and diagnosed between 2004 and 2012 (n = 2292), all patients reviewed by the pathology commission of the BMR (2004-2012; n = 2019), and COD data for all Belgian citizens (2004-2013). Available data were compared in terms of registered cases, histological diagnosis, performed immunohistochemical (IHC) tests, and IHC test results.

Results: Comparison of BCR with BMR registrations showed 94.8% concordant cases. The proportion of MM diagnoses originally reported to BCR with unspecified MM morphology was reduced from 25.8% to less than 1%.

Results: from IHC tests were available for 95.3% of concordant MM cases. Different IHC patterns could be distinguished by MM histology. MM cases registered at BCR for which COD mentioned an MM as underlying cause of death represented 76.4% of deceased cases. MM long-term survivors (survival >3 years; 10.9%) were characterised by distinct clinical and biological characteristics.

Conclusions: A comparison of independent Belgian MM registration databases elucidated under-registration and misclassification and revealed possible reasons for observed discordances. Combining all the available information resulted in enhanced completeness and correctness of MM registration in Belgium and allowed for the identification and characterisation of MM long-term survivors.

Copyright © 2018 Elsevier B.V. All rights reserved.

In plain English

This Belgian study compared three national record systems to check how completely and correctly malignant mesothelioma was recorded. The three were the Belgian Cancer Registry, death certificates, and the Belgian Mesothelioma Registry, whose diagnoses are made by an expert panel of pathologists. The combined cohort was 2887 patients, drawn from both registries' records for diagnosis years 2004 to 2012. Of 2292 mesothelioma cases in the Cancer Registry, 1652 (72.1%) also appeared in the Mesothelioma Registry, and the two agreed on the diagnosis in 94.8%. Another 640 (27.9%) were not found there. Among 1566 agreed cases, the expert information cut the share with an unspecified tissue subtype from 25.8% to less than 1%. Death certificates were linked for 2045 deceased cases, and mesothelioma was the underlying cause of death on 76.4%. Of the 1566 agreed cases, 170 (10.9%) survived at least 3 years. This group was younger, had more women and more peritoneal mesothelioma, and more often had the epithelioid subtype. The authors concluded that comparing the databases revealed under-registration and misclassification, and that death certificates tend to underestimate mesothelioma incidence. The study did not measure asbestos exposure.

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: Population-level registry comparison and record-linkage study of three independent national databases: the Belgian Cancer Registry (BCR), certificates of death (COD) and the Belgian Mesothelioma Registry (BMR), whose diagnoses come from an expert panel of pathologists
• Who was studied: BCR cases were Belgian residents with malignant mesothelioma (MM) or malignant neoplasm of the pleura diagnosed 2004 to 2012: 2292 MM and 52 pleural neoplasm cases. These were compared with 2207 BMR patients for the same diagnosis years. After removing double registrations the combined cohort was 2887 patients. This total includes some BMR cases that the BCR had registered with a diagnosis before 2004 or as non-residents. Death certificate data covered 2004 to 2013.
• Exposure: Not studied. The study compared how mesothelioma diagnoses were recorded and did not collect asbestos exposure data.
• Main results:
  • Of the 2292 MM cases in the BCR, 1652 (72.1%) were also in the BMR, and the diagnosis agreed in 94.8% of these. Cohen's kappa was 0.91 (CI 0.73 to 1.00).
  • For 86 BCR MM cases found in the BMR, the expert panel instead concluded benign disease (n = 39), a secondary tumour mimicking MM (n = 42), or no firm diagnosis (n = 5).
  • 640 (27.9%) of BCR MM cases could not be found in the BMR database.
  • 89 cases reported as MM by the BMR were found in the BCR but had been excluded from the BCR selection. Of these, 40 were registered with a diagnosis before 2004 and 13 had no residence in Belgium.
  • Among the 1566 cases with a concordant MM diagnosis, BMR information reduced unspecified morphology from 25.8% (n = 404) to less than 1% (n = 8).
  • Among concordant MM cases with known morphology, after giving priority to the BMR diagnosis, 75.1% were epithelioid, 13.4% biphasic and 11.5% sarcomatoid. The specified morphology differed between the BCR and BMR for 121 (7.7%) cases.
  • Immunohistochemistry test results were available for 95.3% (n = 1492) of concordant MM cases.
  • Death certificates were linked for 2045 of 2084 MM patients who died between 2004 and 2013 (98.1%).
  • Among BCR MM cases with a linked death certificate, mesothelioma (C45) was the underlying cause of death in 76.4% overall. The authors report a range from 80.5% to 65.2% depending on whether the case was known to the BMR as MM.
  • For 428 BCR MM cases (20.9%) linked to death certificates, mesothelioma was not mentioned as a cause of death.
  • The underlying cause of death recorded for BCR MM patients was lung cancer (C34) for 8.8%, pleural neoplasm (C38.4) for 2.7%, and cancer of unspecified site (C80) for 1.3%.
  • 1726 death certificates gave mesothelioma (C45) as the cause of death; 158 of these (9.2%) were registered at the BCR with a different diagnosis. 220 certificates gave pleural neoplasm (C38.4); 214 of these (97.3%) were registered at the BCR with a different diagnosis.
  • Long-term survivors (at least 3 years) were 10.9% (n = 170) of the concordant MM cases.
  • Compared with other patients, long-term survivors had more peritoneal MM (8.8% vs. 4.5%, p = .010) and a lower male-to-female ratio (2.9 vs. 6.2, p less than 0.001). They were also more often epithelioid (95.9% vs. 72.1%) and younger (median age 66 vs. 71 years).
  • The authors interpreted the death certificate data as tending to underestimate MM incidence in Belgium.
• The authors' conclusion: The authors concluded that consulting independent national data sources helps explain under-registration, over-registration and discordant diagnoses, and that combining the sources improved the completeness and correctness of MM registration.
• Limitations the authors state:
  • The BMR had no information for the 110 MM cases reported to the BCR in 2012.
  • Restrictions on financial compensation may explain why some cases were never reported to the Asbestos Fund, which feeds the BMR.
  • Cases never pathologically confirmed and so never registered at the BCR may lead to an overestimation of survival.
  • Some cases remained inconclusive after the data sources were compared and still need further review.

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: Malignant Mesothelioma, Asbestos Exposure, Cancer Registry, Mesothelioma, Pathology, Histology.

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• Use of exposure registration in the prevention of occupational cancer in Finland — J. Alho, T. Kauppinen, et al. (1988)
• Assessing the component associations of the healthy worker survivor bias: occupational asbestos exposure and lung cancer mortality — A.I. Naimi, S.R. Cole, et al. (2013)
• Disease mapping of zero-excessive mesothelioma data in Flanders — T. Neyens, A.B. Lawson, et al. (2017)
• Asbestos in Belgium: an underestimated health risk. The evolution of mesothelioma mortality rates (1969-2009) — L. Van den Borre, P. Deboosere (2014)

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