Mesothelioma is a cancer arising from asbestos fibers inhaled or ingested into the body and trapped in the mesothelial linings of the lungs (pleural mesothelioma), abdomen (peritoneal mesothelioma), and heart (pericardial mesothelioma).
Pleural mesothelioma is most common, occurring in 75 percent of cases, with peritoneal mesothelioma occurring in about 15+ percent of cases, and pericardial mesothelioma occurring in less than 10 percent.
Mesotheliomas affect thousands of people each year. Mesothelioma was not tracked as a cause of death by federal health officials until 1999, but numbers from that year show an estimated death rate of 2,343 individuals out of a population of about 273 million, based on new reporting. Projecting a rate of increase (from 1990 to 1999) over the subsequent decade, from 2000 to 2010, experts estimate 35,000 yearly deaths from mesothelioma in the long term. More on mesothelioma statistics.
Mesothelioma, in all forms, has an extremely long latency period compared to other cancers. This latency period is generally thought to range from 5 years to 40 years, with a 2007 study from Italy showing an latency period of 43 years for those exposed through their work, and 48 for those who suffered environmental and household exposure.
The U.S. Department of Labor’s Occupational Safety and Health Administration, or OSHA, concurs, noting that mesothelioma has a much longer latency compared to other lung cancers, or 40 years as compared to an average 15 to 20 years. Symptoms of asbestos-related disease like mesothelioma do not usually appear until about 10 to 40 years after first exposure.
The U.S. Environmental Protection Agency, or EPA, the premier national agency for health effects from hazardous chemical exposures (of which asbestos is one), shows the latency period as being between 15-30 years, and adds that asbestos is the only known cause of mesothelioma. The Minnesota Department of Health agrees, noting that all asbestos diseases have a latency period, and that that period is generally between 10 and 40 years.
Experts estimate that more than 28 million Americans have been exposed to asbestos, either through their work, the environment, use of products like ironing board covers and oven gloves (to name a few), or through a family member who brought asbestos fibers home on clothing. A 2004 OSHA report says 1.3 million people are exposed to asbestos through their work.
Mesothelioma symptoms tend to mimic other diseases or illnesses, and mesothelioma is usually isolated as the cause a mere two to three months before a tumor is found, which leads to poor prognoses. The average survival time for people diagnosed with mesothelioma is about 1 to 2 years and mesothelioma is almost always fatal, though scientists and researchers expect, with a new test available to detect mesothelioma, survival rates may improve in the future.
Asbestos itself occurs naturally in six different forms: amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite (the latter three also occurring naturally in non-fibrous forms). Widely used during most of the last century in various building materials and automotive products, to name a few, the mineral is further classified into friable and non-friable forms.
The first category, and the most dangerous (since it readily releases fibers when broken), includes anything containing more than one percent of asbestos (a limit established in 1989 by the EPA for all domestic product); product that, when dry, can be crumbled by mere hand pressure, and; substances like drywall, blown-in insulation, boiler pipe wrapping, and (acoustical) ceiling tiles or insulative and sound-proofing textured ceilings.