Mesothelioma, or cancer of the mesothelium, is diagnosed in about 2,000 to 3,000 individuals in the United States each year, and is becoming more common over time.
The mesothelium is a type of tissue formed by cells that surround the chest cavity, abdominal cavity and heart cavity. It protects the organs of the body by producing a fluid that allows the organs to move, as the lungs must do during breathing.
The most common form of mesothelioma is well-known as pleural mesothelioma, which starts in the chest cavity. About 75 percent of all mesothelioma is of this type, while 10 percent to 20 percent starts in the abdomen (peritoneal mesothelioma). It is rare but not unknown to have a mesothelioma start in the heart cavity (pericardial mesothelioma) (1).
What Causes Mesothelioma?
Most people who develop mesothelioma get it caused by exposure to asbestos, which is a general name given to groups of minerals that could be separated into durable threads. Asbestos is resistant to heat, fire and chemicals and does not conduct electricity, so it has been used in many construction projects and in different uses through the years (2).
A person's risk of developing mesothelioma varies depending on how much asbestos that person has been exposed to and for how long. Many people who develop mesothelioma do so later in life, but it has been diagnosed in younger people and even in children.
Between 70 percent and 80 percent of all mesothelioma cases can be definitively traced back to asbestos exposure, and it is thought that the remainder are asbestos-caused, but without an evidence trail to prove it. Many studies have looked at the links between mesothelioma and asbestos workers.
The death rate from mesothelioma in people who worked with asbestos insulation was 344 times higher than the death rate in the general population. Research indicates that inside 15 years of initial exposure, about 6 percent of all asbestos workers over the age of 35 will die of the disease (3).
It is estimated that about 8 million Americans have been exposed to asbestos, either through occupational hazards, picking it up from the clothing of a family member or going to school or work in a building that contained asbestos. Its estimated that 10 percent to 15 percent of all public schools in America have asbestos in them - as many as 733,000 buildings (4).
Occupational exposure can come from working in the insulation, plumbing, electrical and construction industries, as well as from working with automotive brakes, boilers and in shipyards. People who do demolition work can also be exposed to asbestos, as well as people who live near asbestos factories or work in buildings where asbestos is present (5).
Most people don't contract mesothelioma until 30 to 45 years after their first exposure to asbestos, though the time between exposure and diagnosis can range from 10 to 65 years (6). This long latency period makes diagnosis more difficult, and also accounts for the continued incidence of mesothelioma even after asbestos became known as a threat; several patients who were exposed in 1960 are only now developing the disease. However, the incubation period is not always lengthy; particularly for children, it is possible to be exposed and become ill very quickly thereafter.
How does Asbestos Lead to Mesothelioma?
Asbestos is made of large numbers of tiny fibers that are easily inhaled by a person working with them. The body wants to break down and remove these foreign particles from the lungs, which causes inflammation.
The tiny asbestos particles can get into the smallest and most remote parts of the lungs and they can't be coughed out unless they stick to mucus in the air passages. They can also settle in the tissue around the chest cavity (pleura) or the stomach cavity (peritoneum), where they cause inflammation and lead to mesothelioma (7).
Asbestos fibers in the lungs can damage the organs by forming scar tissue, and the risk of lung cancer is seven times greater for people who have had asbestos exposure compared to people who have not had such exposure. In fact, the three main causes of death for people with intense asbestos exposure are this scarring of the lungs (also known as asbestosis), lung cancer and mesothelioma (8).
How is Mesothelioma Treated?
There are various factors that can impact how mesothelioma is treated, with what stage the cancer is in, the size of the tumor and whether it could be completely removed through surgery, the amount of fluid in the chest cavity, the type and location of the mesothelioma and the age and state of health of the patient (9).
Depending on all these factors, treatment can range from surgery to remove the tumor and a little of of the surrounding tissue, radiation treatment or chemotherapy, drug therapy or removal of part of the lung. There are many different combinations of treatments that are being used as part of clinical trials, including biologic therapy, which attempts to boost the immune system to preclude recurrences (10).
What are the Odds of Surviving Mesothelioma?
Mesothelioma is a very severe disease, with an average survival time of about one year after diagnosis. That's because it is often in a late stage by the time it is diagnosed. The rate of people with mesothelioma who are still alive five years after diagnosis is about 10 percent, but the rate is steadily increasing. Most doctors say the outlook is more favorable for people who are diagnosed today (11).
Working with a doctor who has experience treating mesothelioma, as well as getting as much mesothelioma information as you can, will go a long way toward giving you or your loved one the best possible prognosis.
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