Global Burden of Mesothelioma Uncovered

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In an article made available January 6th online inEnvironmental Health Perspectives researchers reported their findings that globally “one mesothelioma case has been overlooked for every four to five reported cases.” The study’s goal was to estimate the global magnitude ofmalignant mesothelioma since some countries that are known to have extensive historical use of asbestos do not report mesothelioma cases.

Malignant mesothelioma is a rare form of cancer caused specifically byexposure to asbestos. Most cases of mesothelioma are diagnosed 30 years or more after exposure, and are often not diagnosed until the disease is at an advanced stage. Mesothelioma is highly aggressive and is resistant to many standard cancer treatments with the average survival time varying from 4 – 18 months after diagnosis. The World Health Organization (WHO) estimates 43,000 mesothelioma deaths worldwide each year.

Data EvaluationResearchers from the University of Occupational and Environmental Health, Japan, National Taiwan University, and University of Birmingham, England set out to validate and reassess the 2005 estimate that WHO endorses and to compile a set of data correlating asbestos use and mesothelioma.

Using data for country-level asbestos use from 1920 through 1970 and the number of mesothelioma deaths reported between 1994 and 2008 the authors estimated the global burden of mesothelioma mortality at 213,200 over the fifteen years. The researchers determined the cumulative mesothelioma frequency is predictable from cumulative asbestos use based on the total of the 174,300 reported cases. Thus, in the 33 countries that do not report, mesothelioma is predicted at 38,900 cases – or one for every 4-5 cases reported.

This averages to 14,200 cases per year “assuming a flat change rate or approximately 25,000 (38,000) cases in the year 2008 assuming a 10% (20%) annual increase rate.” This is higher than the previously reported value of 10,000 for only the developed regions in the world, but less than the 43,000 mesothelioma deaths estimated for the world in an earlier study from which WHO got their data.

Numbers Could Still be UnderestimatedThe authors said that this study is the first to provide a global estimate of unreported mesothelioma cases by using the “collective experience of countries with data.” Using asbestos-related facts such as length of exposure, the authors made the assumption that cumulative asbestos use subsequently takes a toll reflected in the cumulative mesothelioma count in populations. Some studies indicate that even small amounts of asbestos and infrequent exposure can create a risk for contracting mesothelioma or other asbestos-related diseases.

The authors identified the following potential areas that could result in an underestimation of their numbers:

• Lack of data on the trade of asbestos-containing products (ACP) which would impose additional risk;
• Estimates cannot account for the national experiences of the majority of countries in the world with “no information” on asbestos use (it is possible that USGS information on asbestos use is less complete for the less-developed countries, especially for the earlier years); and
• Underdiagnosis and underreporting of mesothelioma is also a major problem in developed countries.

The researchers caution that the unreporting countries may have economic reasons for not reporting the data and will continue to maintain their production and trade of asbestos while continuing to contribute to the growing global mesothelioma burden. They also state that it is plausible that “the hidden [mesothelioma] burden is substantial in countries with high cumulative use of asbestos, including the asbestos-producing countries such as Russia, Kazakhstan, China and India.”

Prevention of Mesothelioma Through the Ban of AsbestosThe tragedy of mesothelioma is that the disease is completely preventable through the ban of asbestos. While use of asbestos has been curbed in the United States since the late 1970s, the incidence of mesothelioma has been increasing in the United States. Current estimates indicate that close to 3,000 Americans are diagnosed with the disease each year.

According to the Mesothelioma Applied Research Foundation, the study authors urge every country to ban the mining, use, and export of asbestos because mesothelioma can be prevented by eliminating exposure to asbestos.


source: by nancy meredith of mesotheliomahelp.net