Geographic distribution of incidence of pericardial and paratesticular mesotheliomas in the USA

Our plain-English summary of Geographic distribution of incidence of pericardial and paratesticular mesotheliomas in the USA, by S.J. Lowry, N.S. Weiss (Cancer Causes & Control, 2016).

The study

• Authors: S.J. Lowry, N.S. Weiss
• Journal: Cancer Causes & Control
• Published: 2016;27(12):1487-1489
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose: Exposure to asbestos is thought to cause the large majority of pleural mesotheliomas in the USA. It is unknown whether asbestos exposure plays a role in the etiology of rarer forms of mesothelioma, e.g., those located in the pericardium or in the tunica vaginalis of the testis. In order to address this question, we sought to determine whether geographic patterns of incidence of these mesotheliomas have paralleled those of pleural mesotheliomas.

Methods: We used age-adjusted incidence data from the nine populations served by the National Cancer Institute's Surveillance, Epidemiology, and End Results program during 1973-2011. Among men ages ≥50 years, we compared the incidence of pericardial and paratesticular mesotheliomas, respectively, with the incidence of pleural mesothelioma across the nine populations.

Results: The rate of pleural mesothelioma was approximately twice as high in the San Francisco-Oakland (SFO) and Seattle-Puget Sound (SPS) areas compared to the other regions. In contrast, rates of paratesticular and pericardial mesotheliomas were not elevated in SFO (n = 3 paratesticular, 1 pericardial) or SPS (n = 4 paratesticular, 1 pericardial) relative to other regions.

Conclusions: The results of this ecologic study do not support a role for asbestos exposure in the etiologies of either pericardial or paratesticular mesotheliomas; however, this study was limited by small numbers and was unable to directly ascertain asbestos exposure.

In plain English

The authors ran an ecologic study, which compares disease rates between regions rather than looking at individual people's exposures. They used cancer registry data from nine areas in the U.S. National Cancer Institute's SEER program, 1973 to 2011, limited to men aged 50 or older at diagnosis. They reasoned that if pericardial mesothelioma (around the heart) and paratesticular mesothelioma (around the testis) were strongly linked to asbestos, these would be most common where pleural mesothelioma was most common. Pleural mesothelioma rates were about 99 per million person-years in Seattle–Puget Sound and 76 in San Francisco–Oakland, compared with between 31 and 55 elsewhere. Paratesticular rates in those two areas (4 and 3 cases; 0.29 and 0.15 per million person-years) were not higher than the 0.16 to 1.03 seen elsewhere. The single pericardial case in each area did not amount to an elevated rate. The authors concluded that any link between asbestos and these rarer mesotheliomas may not be as strong as for pleural mesothelioma. They noted very small case numbers and no direct exposure data.

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: Ecologic study (brief report) comparing regional incidence rates from cancer registries
• Who was studied: Men aged 50 or older at diagnosis in the nine original SEER registry areas: San Francisco–Oakland, Seattle–Puget Sound, Connecticut, metropolitan Detroit, Hawaii, Iowa, New Mexico, Utah and metropolitan Atlanta. The period was 1973–2011, except Atlanta (1975–2011) and Seattle–Puget Sound (1974–2011).
• Exposure: Asbestos exposure was not measured. The regional incidence of pleural mesothelioma was used as an indicator of asbestos exposure. Higher pleural rates in Seattle–Puget Sound and San Francisco–Oakland had previously been attributed to shipbuilding employment.
• Main results:
  • Pleural mesothelioma among men 50 and older: about 99 per million in Seattle–Puget Sound (99.19, 95% CI 93.88–104.72; 1,370 cases) and 76 per million in San Francisco–Oakland (76.40, 95% CI 72.02–80.97; 1,188 cases). The other seven regions ranged between 31 and 55 per million.
  • Paratesticular mesothelioma: 4 cases in Seattle–Puget Sound (0.29 per million person-years, 95% CI 0.07–0.75) and 3 in San Francisco–Oakland (0.15, 95% CI 0.03–0.46). The other seven regions ranged from 0.16 to 1.03 per million person-years.
  • Pericardial mesothelioma: 1 case in Seattle–Puget Sound (0.11, 95% CI 0.00–0.50) and 1 in San Francisco–Oakland (0.08, 95% CI 0–0.39). Neither rate was elevated relative to the other seven regions.
  • Across the nine regions, the study found no association between the incidence of pericardial or paratesticular mesothelioma and that of pleural mesothelioma.
• The authors' conclusion: The authors concluded that the lack of correlation suggests the association between asbestos exposure and these rarer forms of mesothelioma, if there is one, may not be as strong as the association with pleural mesothelioma.
• Limitations the authors state:
  • It was an ecologic study based on very small numbers of cases.
  • The study could not directly ascertain asbestos exposure, so the strength of evidence is limited.

Topics

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

Medical terms in this study, explained in our Lexicon: Pericardial, Testicular Mesothelioma, Pleural Mesothelioma, Asbestos Exposure, Etiology, Mesothelioma, Pericardium, Tunica Vaginalis.

Related studies

• 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)
• Geographic Co-Occurrence of Mesothelioma and Ovarian Cancer Incidence — S.J. Henley, L.A. Peipins, et al. (2020)
• Geographic distribution of incident mesothelioma in Connecticut men, 1990-99 — A.P. Polednak (2003)
• Epidemiology of mesothelioma of the pericardium and tunica vaginalis testis — G. Mezei, E.T. Chang, et al. (2017)
• Adult paratesticular tumours — B. Khoubehi, V. Mishra, et al. (2002)
• Paratesticular mesothelioma. Report of a case with comprehensive review of literature — M. Bisceglia, D.B. Dor, et al. (2010)

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