Incidence of extrapleural malignant mesothelioma and asbestos exposure, from the Italian national register

Our plain-English summary of Incidence of extrapleural malignant mesothelioma and asbestos exposure, from the Italian national register, by A. Marinaccio, A. Binazzi, D. Di Marzio, et al (Occupational and Environmental Medicine, 2010).

The study

• Authors: A. Marinaccio, A. Binazzi, D. Di Marzio, A. Scarselli, M. Verardo, D. Mirabelli, V. Gennaro, C. Mensi, E. Merler, R. De Zotti, L. Mangone, E. Chellini, C. Pascucci, V. Ascoli, S. Menegozzo, D. Cavone, G. Cauzillo, C. Nicita, M. Melis, S. Iavicoli
• Journal: Occupational and Environmental Medicine
• Published: 2010;67(11):760-5
• Cited by: 46 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: The epidemiology of extrapleural malignant mesothelioma is rarely discussed and the risk of misdiagnosis and the very low incidence complicate the picture. This study presents data on extrapleural malignant mesothelioma from the Italian National Mesothelioma Register (ReNaM).

Methods: ReNaM works on a regional basis, searching for cases and interviewing subjects to investigate asbestos exposure. Classification and code criteria for certainty of diagnosis and exposure modalities are set by national guidelines. Between 1993 and 2004, 681 cases were collected. Incidence measures and exposure data refer to the ReNaM database. Age-standardised rates were estimated by the direct method using the Italian resident population in 2001. Correlations between the incidence of pleural and non-pleural malignant mesothelioma for the 103 Italian provinces were analysed.

Results: Standardised incidence rates (Italy, 2004, per million inhabitants) were 2.1 and 1.2 cases for the peritoneal site (in men and women, respectively), 0.2 cases for the tunica vaginalis testis, and 0.1 in the pericardial site, varying widely in different parts of the country. Mean age at diagnosis for all extrapleural malignant mesothelioma cases was 64.4 years and the men/women ratio was 1.57:1. Median latency was over 40 years for all extrapleural sites combined. The correlation between pleural and peritoneal mesothelioma was 0.71 (Pearson's r coefficient, p<0.001). Modalities of exposure to asbestos fibres were investigated for 392 cases.

Conclusions: The rarity of the disease, the low specificity of diagnosis and difficulties in identifying the modalities of asbestos exposure call for caution in discussing aetiological factors other than asbestos.

In plain English

This study used Italy's national mesothelioma register (ReNaM) to describe mesothelioma arising outside the pleura. Of 9166 mesothelioma cases recorded between 1993 and 2004, 681 were extrapleural: 614 peritoneal, 36 pericardial and 31 in the tunica vaginalis testis. In 2004, the standardised incidence of peritoneal mesothelioma was 2.1 cases per million inhabitants in men and 1.2 in women. It was 0.2 per million for the tunica vaginalis testis and 0.1 for the pericardium, with wide differences between regions. Exposure was assessed for 396 peritoneal cases, and 69.7% (276/396) had occupational, household, environmental or leisure-related asbestos exposure, compared with 81.3% (5040/6203) of pleural cases whose exposure was assessed. The figure was 53.1% among women with peritoneal mesothelioma. Across 103 provinces, peritoneal and pleural incidence were closely correlated (Pearson's r 0.71). The authors noted uneven coverage between regions, that 35.8% of extrapleural cases were not interviewed, and that diagnosis was uncertain, especially in women. The authors concluded that the findings suggest caution in discussing causes other than asbestos.

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: Descriptive analysis of a national, population-based mesothelioma register (incidence rates and interview-based asbestos exposure data)
• Who was studied: 681 extrapleural malignant mesothelioma cases (614 peritoneal, 36 pericardial, 31 tunica vaginalis testis), out of 9166 mesothelioma cases (8485 pleural) recorded in Italy's national register, 1993 to 2004. Regions joined at different times and some did not contribute.
• Exposure: Asbestos exposure, assessed by a standardised questionnaire given to the patient or next of kin. It was classed as occupational (definite, probable or possible), household, environmental, leisure-related, or unknown/improbable, and economic sectors of exposure were recorded. Fibre types were not analysed.
• Main results:
  • Standardised incidence of peritoneal mesothelioma in Italy in 2004 was 2.1 cases per million inhabitants in men and 1.2 in women.
  • Incidence was 0.2 cases per million for the tunica vaginalis testis and 0.1 per million for the pericardium.
  • When only cases with a certain diagnosis were counted, the peritoneal mesothelioma rate was about 20% lower for both men and women.
  • Peritoneal incidence in men ranged from 0.9 per million (Veneto and Apulia) to 6.1 (Piedmont). In women it ranged from 0 in several regions to 3.9 (Piedmont).
  • There were 12.5 pleural cases for every non-pleural case (13.8 to 1 for the peritoneal site), with no significant change over 1993 to 2004.
  • The men-to-women ratio was 2.75 to 1 among pleural cases and 1.57 to 1 among extrapleural cases.
  • Mean age at diagnosis for extrapleural cases was 64.4 years in males (range 18 to 95) and 65.4 years in females (range 19 to 94). For pleural cases it was 68.3 and 69.5 years respectively.
  • Among peritoneal cases with exposure investigated, 69.7% (276/396) had occupational, environmental, household or leisure-related asbestos exposure, compared with 81.3% (5040/6203) of pleural cases with exposure investigated.
  • The proportion with exposure was 53.1% for women with peritoneal mesothelioma and 61.9% for the pericardial group. Among pericardial cases, the figure was 91.7% for men and 22.2% for women.
  • 70% of testicular (tunica vaginalis) cases had ascertained asbestos exposure, which the authors described as close to the pleural figure.
  • Half of the peritoneal cases had been exposed in the asbestos-cement industry, shipbuilding and repair, heavy industry or construction. The asbestos-cement industry accounted for 21.8% of occupationally exposed peritoneal cases, against 4.0% for pleural cases.
  • Mean latency (time from first asbestos exposure to diagnosis) for peritoneal mesothelioma was 43.6 years in men and 40.8 years in women. It was 41.7 years for the 10 men with pericardial disease and 46.8 years for the 13 testicular cases.
  • Across the 103 provinces, pleural and peritoneal incidence were closely correlated: r 0.71 overall, 0.63 in men and 0.65 in women (p less than 0.0001). Correlations of pleural with pericardial and with testicular incidence were weaker and not statistically significant.
• The authors' conclusion: The authors concluded that the Italian surveillance findings suggest caution in discussing causes of extrapleural mesothelioma other than asbestos. They also concluded that misdiagnosis and difficulty identifying exposures, especially for women, must be weighed against suggestions of a weaker link with asbestos.
• Limitations the authors state:
  • The register was not developed uniformly across Italy: regions started at different times and some do not participate, which limits assessment of incidence patterns.
  • Regions investigate asbestos exposure to different depths depending on resources and knowledge.
  • Accepting extrapleural cases without histological diagnosis raises the risk of false-positive cases.
  • 35.8% of extrapleural cases were not interviewed.
  • Diagnosis of extrapleural mesothelioma has low sensitivity and poor specificity, with misdiagnosis a particular risk in women.
  • Investigating occupational, residential and family exposure history appeared especially difficult for women.
  • Some provinces had lower peritoneal rates than expected from their pleural rates, suggesting differences in the ability to detect cases.
  • The absence of shipbuilding, railway and asbestos-cement exposures among the 67 pericardial and testicular cases needs confirmation in a larger sample.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Epidemiology, Misdiagnosis, Incidence, Tunica Vaginalis, Pericardial, Latency.

Related studies

• Epidemiological patterns of asbestos exposure and spatial clusters of incident cases of malignant mesothelioma from the Italian national registry — M. Corfiati, A. Scarselli, et al. (2015)
• Malignant mesothelioma due to non-occupational asbestos exposure from the Italian national surveillance system (ReNaM): epidemiology and public health issues — A. Marinaccio, A. Binazzi, et al. (2015)
• Pleural malignant mesothelioma epidemic: incidence, modalities of asbestos exposure and occupations involved from the Italian National Register — A. Marinaccio, A. Binazzi, et al. (2012)
• Analysis of latency time and its determinants in asbestos related malignant mesothelioma cases of the Italian register — A. Marinaccio, A. Binazzi, et al. (2007)
• Association between asbestos exposure and pericardial and tunica vaginalis testis malignant mesothelioma: a case-control study and epidemiological remarks — A. Marinaccio, D. Consonni, et al. (2020)
• Analysis of survival of mesothelioma cases in the Italian register (ReNaM) — A. Marinaccio, M. Nesti, et al. (2003)

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