New research shows that the number of US mesothelioma cases has not changed much in the last 50 years. It is likely that even more of those cases are related to asbestos exposure than current reports indicate.
Epidemiologists had predicted that the number of mesothelioma cases would decline after the government put asbestos regulations in place in the 1970s. But that has not happened. US mesothelioma cases have stayed steady at about 0.3 percent of all cancers.
At the same time, doctors do not always make the connection between the symptoms of mesothelioma and asbestos exposure, especially among women. Some patients may not even realize they were ever exposed.
As a result, some experts say the number of cases blamed on asbestos exposure is probably lower than it should be.
Incidence of US Mesothelioma Cases
Malignant mesothelioma is a virulent cancer with no known cure. The good news is that new research from the Cleveland Clinic shows 54 percent of US mesothelioma cases are treated now, compared with just 34 percent 50 years ago.
Most cases of mesothelioma are linked to asbestos. The longer or heavier the asbestos exposure, the more likely a person is to eventually develop mesothelioma.
A history of asbestos exposure is often one of the key factors in making a definitive diagnosis. But if the patient is unaware of their exposure, or is never asked about it, their doctor may decide that their mesothelioma is unrelated to asbestos.
For the last 50 years, there have been about 2,500 US mesothelioma cases diagnosed each year. Occupational health expert Richard Lemen, PhD, of Emory University in Atlanta has said that even more of them are likely to be asbestos-related than many doctors realize.
Lemen is former deputy director of the National Institute for Occupational Safety and Health. In an article in the Journal of Toxicology and Environmental Health, Lemen wrote that the government’s updated codes for medical diagnoses, adopted in 2015, would likely bring more cases to light.
“With the implementation of the…ICD-10 coding system, the correlation of mesothelioma with asbestos exposure is expected to rise to approximately 80% in the United States,” said Lemen.
The Mesothelioma Gender Divide Persists
The number of men diagnosed with mesothelioma is about three times higher than the number of women. Men were more likely to work in industries that used asbestos.
Some past studies suggested that women were more susceptible to non-asbestos mesothelioma. But more recent research suggests that the number of US mesothelioma cases associated with asbestos in women is probably just underreported.
“The rate of asbestos-associated mesothelioma is on the rise among women due to better investigation into their histories of asbestos exposure,” reported Lemen.
Doctors may know more about asbestos exposure in women now but the actual percentage of US mesothelioma cases in women has stayed steady. Deaths are up by 2 percent since 2011, according to the CDC. Women continue to make up about a fourth of US mesothelioma cases.
Women often experience second hand asbestos exposure, either by living near a plant or by washing someone else’s contaminated work clothes. In recent years, several legal cases have brought to light the potential presence of asbestos in talcum powder, of which women are the most frequent users.
Cleveland Clinic – Taussig Cancer Institute, Mesothelioma Clinic, http://www.mesotheliomaclinic.org/cleveland-clinic-taussig-cancer-institute/
Lemen, Richard, “Mesothelioma From Asbestos Exposures: Epidemiologic Patterns and Impact in the United States”, Journal of Toxicology and Environmental Health, https://www.tandfonline.com/doi/abs/10.1080/10937404.2016.1195323?journalCode=uteb20