Mesothelioma is a rare but aggressive type of cancer mainly caused by exposure to asbestos. Its development occurs in the mesothelial cells, which collects around some organs, forming a membrane lining called the mesothelium.
While asbestos was widely used for about 100 years in industries like construction, shipbuilding and manufacturing, it was found to be toxic in the 20th century. When asbestos is disturbed and brought into contact with other materials, fibers are released into the air and asbestos fibers become trapped in the body and irritate the mesothelial cells. Over time, inflammation results in the formation of tumors and the development of mesothelioma.
“Mesothelioma is fairly rare in the United States, with about 3,000 new cases being diagnosed each year,” according to the American Cancer Society. “The rate of mesotheliomas in the United States increased from the 1970s to the early 1990s, but since then it has leveled off and even gone down slightly. These changes have largely been seen in men, and are probably related to changes over time in workplace exposures to asbestos.”
Understanding statistics related to mesothelioma can help improve knowledge about the disease and its incidence, as well as prevention and treatment.
Statistics on Mesothelioma Development
About 80 percent of mesothelioma cases are related to asbestos exposure, but there are other reasons that may cause this type of cancer, including zeolites and radiation. Not everyone exposed to asbestos will develop the disease. However, 2 to 10 percent of people who are exposed end up with pleural mesothelioma, the most common form of the disease. While 70 to 90 percent of the mesotheliomas are the pleural type, between 10 and 30 percent are peritoneal mesothelioma; 1 percent is pericardial mesothelioma; and less than 1 percent are testicular mesothelioma cases.
According to esimates from the National Institutes of Health (NIH), about 11 million people were exposed to asbestos between 1940 and 1978. In addition, an estimated 10,000 people in the U.S. continue to be exposed every year to asbestos, which means that about 20 million people are at risk of developing mesothelioma at some point of their lives in the U.S. alone.
The most common ways of being exposed are through the military; asbestos products; occupation; and environment. The latency period, which is the time between exposure and development of the disease, can take 20 to 50 years.
Every year, there are 2,000 to 3,000 new cases of mesothelioma in the country, but the rate has tended to decrease due to greater awareness of the risks of asbestos. But the situation is inconsistent in different parts of the world, and there are countries where the incidence of mesothelioma is still rising.
Since men are more likely to work in jobs susceptible to asbestos exposure, the rate of mesothelioma is lower among women, and men are 4.6 times more likely to be diagnosed with the disease.
About 95 percent of all cases of mesothelioma patients are Caucasian, but the disease is also more likely among Hispanics than Africans or Asians. Mesothelioma is also 10 times more common in people older than 60 than in people younger than 40, while the average age at the time of diagnosis is 69 years old, according to the American Cancer Society.
Between 1999 and 2013, 37,000 people died from mesothelioma in the U.S., and 2,497 of those deaths were in 2013. There is currently no cure for mesothelioma. Treatment consists of surgery, chemotherapy and/or radiation therapy.
On average, about 40 percent of patients with mesothelioma survive at least one year after diagnosis, but after two years the rate decreases to 20 percent. But new treatments are helping people survive as long as seven years after diagnosis. Patients diagnosed in the early stages of the disease have a better prognosis than patients at advanced phases. There are other factors that influence survival rates, as well.
“Research shows that women diagnosed with pleural mesothelioma experience nearly three-fold better survival than men. One study reported that 13.4 percent of women survive for five years after treatment, compared to only 4.5 percent of men,” reports The Mesothelioma Center. “Overall, younger patients have a significantly higher survival rate than older patients. More than 50 percent of patients diagnosed before the age of 50 survive one year, while less than 33 percent of those 75 or older survive the same amount of time. Regardless of race, one-year survival is about the same. From three years on, survival is slightly worse for whites. National Cancer Institute data shows that five-year survival among whites is 7.6 percent, compared to 12.3 percent for blacks.”