Analysis of latency time and its determinants in asbestos related malignant mesothelioma cases of the Italian register

Our plain-English summary of Analysis of latency time and its determinants in asbestos related malignant mesothelioma cases of the Italian register, by A. Marinaccio, A. Binazzi, G. Cauzillo, et al (European Journal of Cancer, 2007).

The study

• Authors: A. Marinaccio, A. Binazzi, G. Cauzillo, D. Cavone, R.D. Zotti, P. Ferrante, V. Gennaro, G. Gorini, M. Menegozzo, C. Mensi, E. Merler, D. Mirabelli, F. Montanaro, M. Musti, F. Pannelli, A. Romanelli, A. Scarselli, R. Tumino, Italian Mesothelioma Register (ReNaM) Working Group
• Journal: European Journal of Cancer
• Published: 2007;43(18):2722-8
• Cited by: 134 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Italy was an important producer of raw asbestos until 1992 (when it was banned) and it is now experiencing severe public health consequences due to large-scale industrial use of asbestos in shipbuilding and repair, asbestos-cement production, railways, buildings, chemicals and many other industrial sectors. Latency of malignant mesothelioma generally shows a large variability and the relationship with the modality of asbestos exposure is still not fully clarified. We present an analysis of latency period among the case list collected by the Italian mesothelioma register (ReNaM) in the period of diagnosis 1993-2001 (2544 malignant mesothelioma (MM) cases with asbestos exposure history). Exposure is assessed retrospectively by interview. Statistical univariate analyses were performed to estimate median and variability measures of latency time by anatomical site, gender and diagnosis period. The role of diagnostic confidence level, the morphology of the tumour and the modalities of asbestos exposure were verified in a regression multivariate model. We found a median latency period of 44.6 years increasing in recent years with a linear trend. Anatomical site, gender and morphology were not relevant for MM latency time whereas a shorter latency period was documented among occupationally exposed subjects (43 years) with respect to environmentally and household exposed ones (48 years).

In plain English

This study looked at latency, the time from first asbestos exposure to diagnosis, among malignant mesothelioma cases in the Italian mesothelioma register (ReNaM). Of 5173 cases diagnosed in 1993–2001, 2544 had a known year of first exposure: 2342 exposed at work and 202 only outside work (household, environmental or hobby-related). Exposure was assessed by interview. Mean latency was 44.6 years (95% CI 44.1–45.0). Among pleural cases, it rose from 41.7 years for those diagnosed in 1993 to 46.2 years in 2001. After adjustment, latency was 48.1 years for household-exposed and 48 years for environmentally exposed cases, significantly longer than 43.4 years for occupationally exposed cases. Tumour morphology and diagnostic certainty were not significantly related to latency. The authors suggested rising latency could reflect reduced workplace exposure intensity before the 1992 ban or better detection of earliest exposure. They noted that only about half the cases could be analysed, that no quantitative exposure measures were available, and that the start of exposure was hard to pinpoint.

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What the study did and found

• Design: Analysis of cases from a national population-based mesothelioma register, with exposure assessed retrospectively by interview; univariate analyses and a multivariate generalised linear regression model
• Who was studied: 2544 malignant mesothelioma cases (2165 men, 379 women) out of 5173 incident cases registered in 12 Italian regions by ReNaM, diagnosed 1993–2001, who had an asbestos exposure history with a known year of first exposure
• Exposure: Asbestos exposure classified as occupational, household, environmental or hobby-related, based on a standardised questionnaire given to the patient or next of kin and coded by an industrial hygienist. Occupational sectors compared included shipbuilding and repair, asbestos-cement and construction. Fiber types and quantitative doses were not analysed.
• Main results:
  • Mean latency for all 2544 cases was 44.6 years (95% CI 44.1–45.0), with a standard deviation of 12 years
  • Among pleural mesothelioma cases, estimated latency was 41.7 years for those diagnosed in 1993 and 46.2 years for those diagnosed in 2001, an increase close to a linear trend (p less than 0.001)
  • In the multivariate model, after age adjustment, mean latency was 48.1 years among household-exposed cases (84 subjects) and 48 years among environmentally exposed cases (98 subjects), significantly longer than among occupationally exposed cases
  • Adjusted mean latency among occupationally exposed cases (2342 subjects) was 43.4 years
  • Among 20 cases exposed through leisure activities, mean latency was significantly shorter, 41.4 years
  • Among female peritoneal mesothelioma cases (19), mean latency was 36.8 years (95% CI 32.3–42.1)
  • Latency was not significantly related to tumour morphology (p = 0.31) or level of diagnostic certainty (p = 0.37)
  • Among occupationally exposed cases, age-adjusted latency was 46.3 years in shipbuilding and repair, 42.3 years in the asbestos-cement industry and 43.7 years in construction
  • Only four of the 2544 cases had a latency shorter than 10 years
• The authors' conclusion: The authors concluded that the main findings were an increase in latency in recent years, close to a linear trend, and a shorter latency among occupationally exposed cases than among environmentally and household exposed cases. They suggested the rise in latency could be due to reduced exposure intensity in workplaces before the ban, or to better detection of the earliest exposure by the regional centres.
• Limitations the authors state:
  • Only about half of the registered cases were eligible for analysis, which could represent a selection bias
  • The retrospective design could miss cases with shorter latency and so overestimate mean latency
  • No quantitative workplace exposure measures or lung fiber measurements were available
  • The onset of exposure was hard to determine precisely; using the start of the first exposed job could overestimate latency
  • The shorter latency in female peritoneal cases raised the possibility of misclassification with female genital cancer
  • The leisure-exposure group was small (20 cases)

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: Latency, Malignant Mesothelioma, Asbestos-Cement, Asbestos Exposure, Mesothelioma.

Related studies

• Incidence of extrapleural malignant mesothelioma and asbestos exposure, from the Italian national register — A. Marinaccio, A. Binazzi, et al. (2010)
• 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 survival of mesothelioma cases in the Italian register (ReNaM) — A. Marinaccio, M. Nesti, et al. (2003)
• 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)
• 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)
• Non-occupational exposure to asbestos and malignant mesothelioma in the Italian National Registry of Mesotheliomas — D. Mirabelli, D. Cavone, et al. (2010)

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