Peritoneal mesothelioma in Italy: Trends and geography of mortality and incidence

Our plain-English summary of Peritoneal mesothelioma in Italy: Trends and geography of mortality and incidence, by S. Conti, G. Minelli, V. Ascoli, et al (American Journal of Industrial Medicine, 2015).

The study

• Authors: S. Conti, G. Minelli, V. Ascoli, A. Marinaccio, M. Bonafede, V. Manno, R. Crialesi, K. Straif
• Journal: American Journal of Industrial Medicine
• Published: 2015;58(10):1050-8
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Peritoneal mesothelioma, a very rare and lethal malignancy, has not been investigated as extensively as pleural mesothelioma, although the role of asbestos exposure in its occurrence is well-known. Data from Italy are relevant, as it was the largest European asbestos producer, and asbestos was widely used in many economic activities.

Methods: A population-based mortality and incidence analysis was performed in Italy. Data sources were the National Multiple-causes-of-death Database (1995-2010) and the Italian Mesothelioma Register (1993-2008).

Results: We found an increasing trend of age standardized mortality rates in men, but no clear trend in women; moreover, we showed significant risks of death in several northern regions, formerly heavy asbestos users; finally, mortality/incidence ratios similar for both genders (about 0.8) were estimated.

Conclusions: The study, based on national data, showed a higher risk of mortality from and incidence of peritoneal mesothelioma in areas with formerly heavy exposure to asbestos.

© 2015 Wiley Periodicals, Inc.

In plain English

This study examined peritoneal mesothelioma in Italy. Using the national multiple-causes-of-death database for 1995–2010 (2004–2005 unavailable), it counted 850 deaths from this cancer, 59.9% in men. Average age-standardized death rates were 0.11 per 100,000 in men (95% confidence interval 0.10–0.12) and 0.06 in women (0.05–0.07). Men's rates rose slightly, an estimated plus 3.18% a year (95% confidence interval 2.2–4.1); women's trend was less clear. Compared with the national population, deaths were significantly higher in Piedmont (standardized mortality ratio 213; 90% confidence interval 185–242), Lombardy (122; interval misprinted), Friuli-Venezia Giulia (200; 151–261) and Liguria (145; 110–187), northern regions the authors described as having had heavy asbestos presence. Deaths were significantly lower in several central and southern regions. The mesothelioma register recorded 1,017 new cases in 1993–2008. In regions with complete data, the 2000–2008 ratio of deaths to new cases (excluding 2004–2005; Lazio and Campania from 2001) was 0.76 in men and 0.77 in women. The authors concluded the study corroborates this cancer's relation with asbestos exposure at a geographical level. They noted possible misclassification, including with ovarian cancer in women.

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-based analysis of national mortality and incidence data (death-certificate database and mesothelioma register)
• Who was studied: Italy. Mortality: 850 deaths due to peritoneal mesothelioma, 1995–2010 (2004–2005 excluded as unavailable; provinces of Trento and Bolzano excluded); 508 men and 342 women. Incidence: 1,017 cases in the Italian Mesothelioma Register (ReNaM), 1993–2008; 599 men and 418 women.
• Exposure: Asbestos was considered at the level of geographic areas, not individuals. The authors described the regions with excess deaths as having had heavy presence of asbestos (asbestos cement plants, a chrysotile mine, shipbuilding and repair, railway carriage construction and repair).
• Main results:
  • Of the 850 deaths due to peritoneal mesothelioma, 59.9% were in men and 40.1% in women. Median age at death was 67 years for men and 68 years for women.
  • The mean age-standardized death rate for 1995–2010 was 0.11 per 100,000 (95% CI 0.10–0.12) in males and 0.06 per 100,000 (95% CI 0.05–0.07) in females.
  • In men, the Joinpoint model of age-standardized death rates over the whole period showed a slightly increasing trend: estimated annual percentage change of plus 3.18 (95% CI 2.2–4.1). The highest rate was in 2006.
  • In women, the trend was less clear, with the highest rate (0.10) in 2001. The model showed an increase until 2001 (estimated annual percentage change plus 6.7, 95% CI 0.1–14.1), followed by what the authors called a modest decrease.
  • Compared with the national population, there were significant excess deaths in the northern regions of Piedmont (SMR 213; 90% CI 185–242), Lombardy (SMR 122; its 90% CI is printed as '108–0138' and is not restated here), Friuli-Venezia Giulia (SMR 200; 90% CI 151–261) and Liguria (SMR 145; 90% CI 110–187). Emilia-Romagna's excess (SMR 107) was not statistically significant.
  • There were significant deficits in the central regions of Umbria (SMR 35) and Marche (SMR 50), and in the southern regions of Basilicata (SMR 35), Calabria (SMR 29), Sicily (SMR 53) and Sardinia (SMR 35).
  • The register identified 1,017 incident cases in 1993–2008 (58.9% men, 41% women). Most were classified as certain: 496 men (83%) and 338 women (81%). In 2008, age-standardized incidence rates were 0.26 per 100,000 in men and 0.12 per 100,000 in women.
  • The mortality/incidence ratio was calculated only for regions with complete mortality and incidence data. It covered 2000–2008, excluding 2004–2005, and 2001–2008 for Lazio and Campania. The ratio was 0.76 in men (256 deaths, 335 incident cases) and 0.77 in women (183 deaths, 238 incident cases). In northern Italy it was 0.71 in men and 0.67 in women.
• The authors' conclusion: The authors concluded that the study corroborates the relation of peritoneal mesothelioma with asbestos exposure at a geographical level. They said it does not explain why this cancer has a lower male-to-female ratio than pleural mesothelioma, and suggested studying misclassification with ovarian cancer.
• Limitations the authors state:
  • Mortality trends are hard to interpret because of possible misclassification in mortality data and the small number of cases.
  • In women, peritoneal mesothelioma may be misclassified as ovarian cancer.
  • Incidence data were incomplete because regional register centers started in different years, so the authors did not perform an incidence trend analysis.
  • Mortality data for 2004–2005 were not available.
  • The mortality and incidence sources cover different time windows and different geographic areas.

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: Peritoneal Mesothelioma, Pleural Mesothelioma, Asbestos Exposure, Mesothelioma.

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