What is mesothelioma?

Mesothelioma is a rare type of cancer that starts in mesothelial cells, which make up the lining around certain body parts. Also known as malignant mesothelioma, this cancer usually occurs in people exposed to asbestos, but symptoms may not develop until 10-50 years later.

The most common type of mesothelioma is pleural mesothelioma, which affects the tissue in the lining of the lungs. But the cancer can develop in other areas of the body, too. There are only about 3,000 cases of mesothelioma diagnosed each year in the United States.

Types of mesothelioma

There are four main types of mesothelioma—based on where in the body the cancer first starts to form. Pleural mesothelioma makes up more than 80% of all mesothelioma cases. Mesothelioma can also develop in the peritoneum (lining of the abdomen), pericardium (the lining of the heart) or the lining of the testicles.

  • Pleural mesothelioma

    Pleural mesothelioma in the lungs happens when you breathe in asbestos fibers and they make their way into the pleural lining. Over an extended period, this may cause cancer cells to grow.

  • Peritoneal mesothelioma

    Peritoneal mesothelioma affects the abdomen's lining, which surrounds many digestive organs. Peritoneal mesothelioma accounts for approximately 15-20% of cases.

  • Pericardial mesothelioma

    Pericardial mesothelioma is a rare type of the condition, making up only 1% of all cases. This type of mesothelioma starts in the pericardium, which is the sac around the heart.

  • Testicular mesothelioma

    This type of mesothelioma starts in the lining of the testes. It’s very rare, with only a few hundred cases diagnosed at any time in the United States. While asbestos exposure is linked to this type of mesothelioma, the exact cause isn’t yet completely understood.

What are mesothelioma symptoms?

Mesothelioma symptoms can vary depending on where in the body the cancer starts to grow, and it may take a long time for symptoms to appear after asbestos exposure. At first, your symptoms may be similar to other common conditions, like flu or pneumonia. One common symptom of mesothelioma is pleural effusion, fluid buildup in the pleural lining of the chest. You may also have symptoms that affect the whole body, such as fatigue.

Common mesothelioma symptoms

As mesothelioma starts to grow, it can affect nearby organs, causing many different symptoms:

  • Shortness of breath or trouble breathing
  • Fluid around the lungs, abdomen, heart or testicles
  • Chest, back, rib, abdomen or testicular pain
  • Dry cough and hoarseness
  • Loss of appetite and weight loss
  • Fatigue
  • Digestive problems
  • Swelling in the face, arms or legs
  • Irregular heartbeat or palpitations

Learn more about mesothelioma symptoms

When to see a doctor

If you have a history of asbestos exposure, it’s important to pay attention to any signs of mesothelioma. Symptoms such as chest pain, shortness of breath, abdominal pain or frequent infections could be caused by mesothelioma. If you have any ongoing symptoms or something feels off, schedule a visit with your doctor.

Mesothelioma causes

Mesothelioma occurs when abnormal cells in the lining of the lungs, heart, abdomen or testes start to grow rapidly. We don’t fully understand why this happens with mesothelioma, but doctors know some factors that may put you more at risk.

The majority of mesothelioma cases—about 80% —are linked to asbestos exposure. But other factors like your environment, health history, lifestyle or genetics could also play a role in causing mesothelioma.

Mesothelioma risk factors

Knowing your risk of mesothelioma and its symptoms means that you and your healthcare team can be proactive in detecting any signs of the disease. While some risk factors may be out of your control, there are steps you can take to protect yourself.

  • Asbestos exposure

    Asbestos exposure is the leading risk factor for developing mesothelioma. When you breathe in or swallow tiny asbestos fibers, these fibers can get into your chest or abdomen. Over time, doctors believe these fibers cause irritation, eventually leading to an increased chance of abnormal cell DNA changes, causing mesothelioma.

  • Occupational exposure

    You have a higher chance of asbestos exposure if you work in certain occupations. Talk with your doctor about your risk and what you can do to prevent exposure and protect your health.

    Some high-risk occupations include:

    • Mine workers
    • Construction and home remodelers
    • Auto and aircraft mechanics
    • Shipyard workers and ship crews
    • Textile mill workers
    • Oil refinery workers
    • Electricians
    • Plumbers
    • Pipefitters
    • Insulators
    • HVAC workers
    • Demolition workers
    • Machine operators
    • Military personnel
    • Firefighters
  • Other risk factors

    While asbestos exposure is the leading risk factor of mesothelioma, a few other factors may increase your risk, too. These could include a family history of the condition, smoking, age or previous radiation treatment. Genetics may play a role in developing mesothelioma, but only about 1% of people who get mesothelioma have an inherited genetic change.

How is mesothelioma diagnosed?

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If you’re having any symptoms of mesothelioma, especially if you’ve been exposed to asbestos, your doctor has several tools to help diagnose your condition. You’ll likely have imaging or blood tests to give your team more information. A biopsy will take tissue samples to diagnose mesothelioma.

If mesothelioma is found through your biopsy, your care team will also classify your condition based on the specific type of cells involved. The most common cell type in mesothelioma is epithelioid cells—found in about 70% of cases. Another less common type is sarcomatoid cells. If you have both types of cells, it’s called biphasic mesothelioma.

Medical history and physical exam

Your care starts with a visit to the doctor, where you'll discuss your medical history and any risk factors for mesothelioma, such as asbestos exposure. During your exam, your doctor will listen to your heart and lungs, tap your abdomen or chest and look for signs of fluid buildup.

If you have symptoms of pleural mesothelioma, you may also have a pulmonary function test to check how your lungs are working. As mesothelioma shares symptoms with many other conditions, your doctor may order additional tests after your exam to help with diagnosis.

Imaging tests

While imaging tests alone can't diagnose mesothelioma, they can give your care team important details about your health and look for signs that might indicate mesothelioma. You will have access to several imaging tests, including:

  • Chest X-ray: A chest X-ray gives your care team a closer look at your lungs. You may have this imaging test if you have symptoms of pleural mesothelioma.
  • Computed tomography (CT): A CT scan combines multiple X-rays to provide detailed images of your body. This test helps find where mesothelioma may be located and the stage of mesothelioma after you are diagnosed.
  • Echocardiogram: An echocardiogram is an ultrasound imaging test of the heart and shows signs of fluid in the sac around your heart. It helps with the diagnosis of pericardial mesothelioma.
  • Magnetic resonance imaging (MRI): An MRI uses magnets and radio waves to create images of the body and look for signs of mesothelioma. Your care team sometimes uses this test to look for signs of mesothelioma spreading to the diaphragm.
  • Positron emission tomography (PET): A PET scan uses an injection of radioactive sugar to help highlight any areas of cancer cells inside the body. It may help your care team tell the difference between cancer and scar tissue that has been seen on another imaging test.

Blood tests

There isn't a specific blood test to diagnose mesothelioma. However, high levels of certain substances in your blood could indicate the condition. Your doctor may also order other blood tests to check the function of your liver or kidneys.

Biopsies

If your exam, imaging or blood tests show signs of mesothelioma, lung cancer or another type of cancer, your doctor will order a biopsy to take samples of fluid or tissue. These samples are examined in the lab to look for cancer cells and diagnose your condition.

If you have fluid buildup, your care team can take a sample using a hollow needle. A thoracentesis procedure will take a fluid sample from the lining around your lungs. When fluid is taken from around the heart, it’s called pericardiocentesis; when taken from the abdomen, it's called paracentesis.

  • Needle biopsies: Your care team may use a needle to take a small tissue sample in a mass or lymph node to help diagnose mesothelioma. Sometimes, imaging will be used to help guide the needle to the right spot.
  • Endoscopic biopsies: If the area needing to be biopsied can't be reached using a needle, you may have an endoscopic biopsy to take samples. These procedures use a thin tube with a camera inserted into the body through small incisions. Thoracoscopy is used to take biopsies in the chest and laparoscopy is used to take biopsies in the abdomen.
  • Open surgical biopsy: Sometimes, your care team may need to use a more invasive procedure with a larger incision to reach a mass, take samples or remove it. Thoracotomy is a surgical procedure that uses a larger incision in the chest, and laparotomy uses a larger incision in the abdomen.

Mesothelioma stages

When you're diagnosed with mesothelioma, your care team will place your cancer into one of four stages. Your cancer stage is important in your mesothelioma care because it helps you and your team make informed choices about the right treatment options for you. Stages 1 and 2 are considered early-stage cancer. Stages 3 and 4 are more advanced.

Stage 1

Stage 1 mesothelioma is still localized and hasn't spread. You may have more treatment options during this stage, such as surgery.

Stage 2

Stage 2 mesothelioma has spread into nearby tissues or lymph nodes. Sometimes, surgery is still an option.

Stage 3

Stage 3 mesothelioma has started to spread further away from its original location. At this stage, you may have fewer treatment options.

Stage 4

Stage 4 mesothelioma has spread to distant areas of the body. Care plans at this stage often focus on managing symptoms.

Treatment for mesothelioma

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When it comes to treatment for mesothelioma, this rare type of cancer requires a specialized, team approach. You may visit multiple doctors who will work together to create a plan for your needs and specific stage of cancer.

Surgery is a standard treatment option in the earlier stages of mesothelioma. Your treatment could also include chemotherapy, radiation therapy, immunotherapy, targeted therapies, pain management or palliative care. Often, you’ll have a combination of treatments.

Surgery

Surgery can be used to treat mesothelioma to remove as much of the cancer as possible. Though often, mesothelioma can’t be completely removed with surgery. The type of surgery that your care team recommends will depend on the location of your cancer and how much your mesothelioma has spread.

  • Extrapleural pneumonectomy: This extensive and complex surgery aims to remove all the areas of cancer caused by pleural mesothelioma, like a pneumonectomy, where your surgeon will remove one of your lungs. An extrapleural pneumonectomy also removes the lining in the chest on that same side, part of your diaphragm, lymph nodes and, in some cases, the sac around your heart.
  • Pleurectomy and decortication: During this surgery, known as P/D, your doctor removes the lining around the affected lung and the pleural coating around your lung and diaphragm on that side of the body.
  • Debulking: Debulking surgery removes as many areas of cancer as possible in the lining of the lungs or abdomen, while leaving as much healthy tissue in place as possible. When used in the lining of the lungs, it may be called a partial pleurectomy.
  • Pleurodesis: Pleurodesis is a procedure that removes fluid buildup and then uses chemicals to make scar tissue in the lining of the lungs. This process prevents any additional fluid from building up in the space.

Chemotherapy

Chemotherapy is often used in the care of mesothelioma. It’s sometimes given before, after or during surgery. If surgery isn’t an option for you, these cancer-killing drugs may be your primary treatment.

Two common types of localized chemotherapy given during surgery are hyperthermic intraperitoneal chemotherapy and hyperthermic intrathoracic chemotherapy. During these types of chemotherapy, a high dose of heated chemotherapy drugs is placed straight into the abdomen or the chest.

Radiation therapy

The primary type of radiation therapy for mesothelioma is external beam radiation therapy, which uses high-energy rays from outside the body to destroy cancer cells. When radiation therapy is delivered inside the body, it's called brachytherapy.

Radiation therapy is more common as a treatment option for pleural mesothelioma. When all the cancer can’t be removed by surgery, it may help destroy the cancer cells that remain or be used as an option to manage and reduce symptoms.

Immunotherapy

Immunotherapy helps your immune system find and attack cancer cells and typically has fewer side effects than chemotherapy. It could be a treatment option if you have pleural mesothelioma that can't be treated using surgery.

The primary type of immunotherapy drug approved to treat mesothelioma is checkpoint inhibitors. They help the body recognize cancer cells by blocking a specific protein in the cells.

Targeted therapy

Targeted therapies are drugs that target specific changes or attributes of mesothelioma cancer cells. One of the most common types of targeted therapy is monoclonal antibody therapy. In mesothelioma treatment, a monoclonal antibody targets a cancer cell’s protein that promotes blood vessel growth. By blocking this protein and stopping blood vessel formation, the therapy prevents the cancer cells from receiving vital nutrients needed to grow.

Finding specialized mesothelioma cancer treatment

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Frequently asked questions

  • How common is mesothelioma?

    Mesothelioma is not very common. In the United States, only about 3,000 cases are diagnosed each year. And since the 1990s, cases of this type of cancer have slightly declined.

  • How much asbestos exposure causes mesothelioma?

    Even one-time exposure to asbestos increases your risk of mesothelioma and repeated or prolonged exposure increases your risk even more. It’s estimated that 8-13% of people who have long-term asbestos exposure will be diagnosed with mesothelioma.

  • Is mesothelioma curable?

    For most people, mesothelioma is not curable. But you have treatment options that can reduce symptoms and prolong your life. Research and clinical trials continue to find more ways to treat mesothelioma and improve the quality of life of those living with the condition.

  • Is mesothelioma lung cancer?

    No. Lung cancer develops in the lungs, and mesothelioma starts in the cells that make up the tissue that surrounds the lungs, heart, abdomen or testes. While asbestos may put you at risk for both lung cancer and mesothelioma, care of these cancers is often different.

  • What causes mesothelioma other than asbestos?

    In general, your risk increases with age, and men are much more likely to develop mesothelioma. Some studies have also shown an increased risk if you have radiation treatment or are exposed to minerals called Zeolites. A rare genetic mutation called BAP1 may also increase your risk.