Mesothelioma is an aggressive cancer that usually stems from exposure to asbestos. It affects the mesothelial cells, which occur in the lining that covers the outer surface of the body’s organs.
Mesothelioma most commonly affects the pleura, or the lining of the lungs, but it can also appear in the lining of the heart and the abdomen.
It is relatively rare. Every year there are about 3,000 new diagnoses in the United States.
There is no cure for mesothelioma, but palliative therapy may improve a person’s quality of life.
Mesothelioma is an aggressive form of cancer, meaning that it progresses and spreads quickly.
There are three types:
Pleural mesothelioma: This is the most common form. It affects the pleura, the lining around the lungs.
Peritoneal mesothelioma: This is the second most common form. It attacks the lining of the abdomen, called the peritoneum.
Pericardial mesothelioma: This is the rarest form. It affects the protective layer of the heart, called the pericardium.
After diagnosis, 55% of people will survive for at least another 6 months, 35% for a year, and 9% for another 5 years or longer. The survival rates vary, however, between types.
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On average, mesothelioma takes 30–45 years to appear.
Some people experience symptoms after 10 years, while others remain asymptomatic for 50 years. The length of time will depend, to some extent, on the intensity of the asbestos exposure. Genetic and other individual factors may also play a role.
The average age at diagnosis of pleural mesothelioma is 72 years.
Symptoms vary, depending on which part of the body the disease affects.
The symptoms of pleural mesothelioma include:
- shortness of breath
- coughing, often with pain
- sudden and unexplained weight loss
- pain under the rib cage
- detectable lumps under the skin in the chest area
- lower back pain
- discomfort in the side of the chest
- difficulty swallowing
A person with peritoneal mesothelioma may experience:
- unexplained weight loss
- abdominal pain and swelling
- lumps in the abdomen
- nausea and vomiting
Pericardial mesothelioma can cause:
- low blood pressure
- shortness of breath
- fluid retention, or edema, often in the legs
- heart palpitations
- extreme fatigue following light exertion
- chest pain
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There is a direct link between mesothelioma and exposure to asbestos, a combination of six minerals comprising long, thin fibers.
Asbestos refers to a group of minerals that exist as fibers or bundles. These fibers occur naturally in the soil or rocks in many parts of the world. Asbestos consists of silicon, oxygen, and some other elements.
Products that contain asbestos include:
- building materials, including siding, floor tiles, ceiling materials, and roof shingles
- friction products, such as brake parts
- heat resistant fabrics, packaging, coatings, and gaskets
In the past, builders often used asbestos to insulate products and buildings and make them soundproof or fireproof.
When a person installs, repairs, or demolishes asbestos products, the fibers can become airborne.
People can then inhale or swallow them, and they become permanently lodged in the lungs or gastrointestinal tract. In some cases, they may remain there for decades. The particles can also affect other organs.
In time, mesothelioma can develop from these fibers.
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The likelihood of developing mesothelioma depends on the extent of a person’s exposure to asbestos. Factors that play a role include the duration of the exposure, how much the person inhaled, and the type of asbestos fiber.
People in jobs with high exposure, such as those working on construction sites, steel mills, or power plants, have the highest risk of developing the disease.
Even family members who have never entered an asbestos-rich environment can be at risk. If a worker accidentally carries fibers home in their clothing, other members of the household can inhale these particles.
People have known about the link between asbestos and cancer and other lung diseases for more than 60 years. Nevertheless, the World Health Organization (WHO) estimated that close to 125 million people globally had exposure to asbestos at work in 2005.
Regulations in industrialized countries have reduced the risk of exposure to asbestos. However, its use remains largely unregulated in many nations. As a result, a high number of people are still at risk.
Although it is much less common, mesothelioma may also develop following exposure to radiation therapy or as a result of breathing in fibrous silicates, such as erionite, zeolite, and intrapleural thorium dioxide.
People often do not present with symptoms of mesothelioma until the later stages of the disease. The doctor will ask the person about their personal and family medical history and conduct a physical examination.
If the doctor suspects mesothelioma, they will also ask about previous employment and any other possible exposure to asbestos.
A biopsy can confirm the diagnosis. The doctor will take a tissue sample from the affected area, which is usually the chest or abdominal area.
A biopsy can show if cancer is present and allow a doctor to confirm what type and how advanced it is.
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The stage of cancer refers to how far it has spread.
At stage 1 (localized), mesothelioma only affects the area where it started, which is usually the lining around the lung.
At Stage 4 (distant), it has spread to distant organs and affects the whole body.
Most people will receive a diagnosis of mesothelioma at a late stage.
Treatment will depend on several factors, including:
- the location of the cancer
- the stage
- the person’s age and overall health
Mesothelioma is usually aggressive, and diagnosis tends to take place at a late stage. For this reason, only about 35% of those who receive a diagnosis will survive another year.
Surgery is not an option at this stage, and treatments such as chemotherapy or radiation may trigger severe adverse effects.
Sometimes, the only option may be to manage the person’s pain and keep them as comfortable as possible.
Options for treatment
Depending on the stage of mesothelioma, treatment options include:
Surgery: Removing all or part of the cancer in the early stages may slow tumor growth and relieve symptoms. If the surgeon cannot remove the whole tumor, they may remove part of it to reduce its size. Sometimes, a surgeon will remove the lining around the lungs or abdominal cavity to relieve symptoms. The person may need a catheter after surgery to drain fluid from the lungs.
Chemotherapy: If surgery is not possible, a doctor may recommend chemotherapy to reduce a tumor’s size and slow its progress. Chemotherapy can shrink a tumor before surgery, making it easier to remove. After surgery, this treatment can help remove any remaining cancer cells.
Radiation therapy: This treatment may help reduce the severity of symptoms in those with pleural mesothelioma. Sometimes, it can help prevent metastasis after a biopsy or surgery. Various combinations of treatments are possible, and individual factors will determine the best option. A doctor will discuss suitable choices with the individual.
Malignant mesothelioma is an aggressive type of cancer, and it is usually life threatening. It also takes a long time to appear, so diagnosis often occurs when the cancer is already advanced.
Being aware of the dangers of asbestos exposure can help a person protect themselves and their family.
The Environmental Protection Agency (EPA) have strict rules about the use and disposal of asbestos.
Anyone who has concerns that their home or work environment may expose them to asbestos can contact the EPA or their local health authority to find out what action they can take.