Time trend of mesothelioma incidence in the United States and projection of future cases: an update based on SEER data for 1973 through 2005

Our plain-English summary of Time trend of mesothelioma incidence in the United States and projection of future cases: an update based on SEER data for 1973 through 2005, by B. Price, A. Ware (Critical Reviews in Toxicology, 2009).

The study

• Authors: B. Price, A. Ware
• Journal: Critical Reviews in Toxicology
• Published: 2009;39(7):576-88
• Type of article: Review
• Cited by: 146 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The time trend of mesothelioma incidence and projections of future cases provide useful information for analyzing proposed public health interventions where asbestos exposure may be an issue, evaluating regulatory proposals, and estimating the remaining potential costs of programs to compensate individuals with asbestos-related diseases. We used the April 2008 release of Surveillance, Epidemiology, and End Results (SEER) data, which covers 1973 through 2005, to analyze the time trends in age-adjusted mesothelioma incidence and to estimate an age and birth-cohort model to project the number of future mesothelioma cases. The increase in the number of SEER cancer registries from 13 to 17 in 2000 had little effect on the time pattern of age-adjusted mesothelioma incidence, and the pattern over time of pleural mesothelioma was indistinguishable from the pattern for total mesothelioma defined as sum of pleural and peritoneal cases. Our analysis suggests that the SEER registries viewed as a sample of the U.S. population over-represents high mesothelioma incidence, a fact that we accounted for in our projections. For 2008 we estimate approximately 2,400 cases, with asbestos the likely cause in 58%. We project that asbestos will no longer be a factor in mesothelioma cases after the year 2042. For 2008 through 2042, we estimate slightly more than 68,000 total cases, with asbestos the likely cause in 34%.

In plain English

The journal labeled this a review article, but it reported the authors' own analysis of U.S. cancer registry (SEER) data for 1973 through 2005, drawn from 9, then 13, then 17 registries. The authors tracked age-adjusted mesothelioma rates and built an age and birth-cohort model to project future cases. Male rates rose, peaked and leveled off in the mid-1990s, then appeared to begin declining. Female rates were flat at about 0.3 per 100,000 until 1983 and about 0.4 afterward. Pleural-only trends looked the same as pleural plus peritoneal trends. Judging that SEER over-represents high-mesothelioma areas, the authors weighted their projections. For 2008 they projected 557 female and 1,850 male cases, with asbestos exposure behind 70.8% to 72.7% of the male cases. For 2008 through 2042 they projected about 23,000 cases likely caused by asbestos. The authors concluded that after 2042 they would not expect asbestos-caused cases, and that U.S. asbestos exposure in 2008 was not a significant risk factor. They described their check of how representative SEER is as indirect and coarse, and said the 2042 date depends on modeling choices.

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: Analysis of cancer registry data with statistical modeling. The authors analyzed time trends in age-adjusted incidence and fitted an age and birth-cohort model to project future cases. The journal labels it a review article.
• Who was studied: Mesothelioma cases (pleural and peritoneal, males and females) recorded in U.S. SEER cancer registries: 9 registries for 1973–2005, 13 registries for 1992–2005, and 17 registries for 2000–2005. Projections were made for the U.S. through 2054.
• Exposure: Asbestos exposure was not measured for individuals. It was inferred from birth-cohort patterns. Asbestos-related female cases were estimated for women born 1900–1924 who may have worked in shipyards and other heavy industry in 1940–1944, where the authors say women were likely exposed to amphibole asbestos. Male background cases were set equal to projected female background cases.
• Main results:
  • For males, age-adjusted incidence increased, peaked and leveled off in the mid-1990s, then appeared to begin declining.
  • For females, age-adjusted incidence was flat at about 0.3 cases per 100,000 until 1983, then about 0.4 per 100,000.
  • Trends for pleural mesothelioma alone appeared identical to trends for pleural plus peritoneal mesothelioma combined.
  • The authors compared county mesothelioma mortality. Low-rate and high-rate counties held 80% and 20% of the U.S. population, but 70% and 30% of the SEER population. The authors read this as SEER over-representing high-incidence areas.
  • Using state asbestosis mortality as a stand-in for exposure, 6.5% of the U.S. population lived in high-exposure states (above the 90th percentile), compared with 15.5% of the SEER population.
  • Projected cases for 2008: 557 among females and 1,850 among males.
  • Among males in 2008, the projected share of cases resulting from asbestos exposure was 70.8% to 72.7%.
  • Among females in 2008, projected asbestos-related cases were 3 (0.5%) for women who worked in shipyards, plus 15 to 50 (2.7% to 9.5%) for women exposed in other World War II industries.
  • For 2008 through 2042, males were projected to have 45,352 cases, with 49.9% to 50.2% resulting from asbestos exposure.
  • For 2008 through 2042, projected asbestos-related female cases were 11 (0.05%) for women who worked in shipyards, plus 61 to 206 (0.3% to 0.9%) for women exposed in other World War II industries.
  • For 2008 through 2042, about 23,000 cases in total were projected as likely caused by asbestos.
  • Under the preferred weighted model, total projected cases for 2008 through 2054 were 53,747 for males and 31,176 for females.
  • Estimated risk of background (non-asbestos) mesothelioma was 3.8 to 4.3 per million per year, averaged across all ages in the population 15 and older. Lifetime risk was 3.8 per 10,000. The authors said these estimates apply to both females and males.
  • The authors interpreted the lack of a time trend in female incidence as suggesting that most female cases may not be caused by asbestos exposure.
• The authors' conclusion: The authors projected that male and female case numbers would converge around 2042. They interpreted this to mean that after 2042 they would not expect asbestos-caused cases. They concluded that, given the long latency period, neither occupational nor environmental asbestos exposure in the U.S. in 2008 is a significant risk factor for mesothelioma.
• Limitations the authors state:
  • The check of how well SEER registries represent U.S. mesothelioma incidence was indirect and gave only a coarse measure.
  • The 10% and 90% weights given to the high- and low-incidence registry projections were chosen partly by the authors' judgment.
  • The convergence year is sensitive to which birth cohorts are used. It moved from 2042 to 2052 when the averaging period ended in 1959 instead of 1949.
  • Estimates for birth cohorts after 1949 lack precision and may be biased, because those people were too young to give reliable incidence estimates.
  • Setting male background cases equal to female background cases may give an upper bound for male background cases.
  • The male model based on self-weighting data from 17 registries did not fit the data acceptably, and the authors did not investigate this further.

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: Mesothelioma, SEER, Asbestos Exposure, Epidemiology, Pleural Mesothelioma.

Related studies

• Mesothelioma trends in the United States: an update based on Surveillance, Epidemiology, and End Results Program data for 1973 through 2003 — B. Price, A. Ware (2004)
• Re: "Mesothelioma trends in the United States: an update based on surveillance, epidemiology, and end results program data for 1973 through 2003" — J.H. Lange (2004)
• Recent trends in mesothelioma incidence in the United States — R. Spirtas, G.W. Beebe, et al. (1986)
• Incidence of mesothelioma in Lombardy, Italy: exposure to asbestos, time patterns and future projections — C. Mensi, S. De Matteis, et al. (2016)
• Response to Letter to the Editor Regarding "Ambient Asbestos Fiber Concentrations and Long-Term Trends in Pleural Mesothelioma Incidence Between Urban and Rural Areas in the United States (1973-2012)" by Finkelstein — K.A. Keeton, M.E. Glynn, et al. (2018)
• Letter Concerning: Glynn ME, Keeton KA, Gaffney SH, Sahmel J. Ambient Asbestos Fiber Concentrations and Long-Term Trends in Pleural Mesothelioma Incidence Between Urban and Rural Areas in the United States (1973-2012). Risk Analysis 2018;38(3):454-471 — M.M. Finkelstein (2018)

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