Malignant Mesothelioma

General Information | Treatment Options | Additional Resources

General Information
  • About
  • Risk Factors
  • Signs & Symptoms
  • Detection
  • Stages

Malignant mesothelioma is a disease in which malignant (cancer) cells form in the lining of the chest or abdomen.

Malignant mesothelioma is a disease in which malignant (cancer) cells are found in the pleura (the thin layer of tissue that lines the chest cavity and covers the lungs) or the peritoneum (the thin layer of tissue that lines the abdomen and covers most of the organs in the abdomen). This summary is about malignant mesothelioma of the pleura.

Being exposed to asbestos can affect the risk of developing malignant mesothelioma.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor.

Many people with malignant mesothelioma have worked or lived in places where they inhaled or swallowed asbestos. After being exposed to asbestos, it usually takes a long time for malignant mesothelioma to occur. Other risk factors for malignant mesothelioma include the following:

  • Living with a person who works near asbestos.
  • Being exposed to a certain virus.

Possible signs of malignant mesothelioma include shortness of breath and pain under the rib cage.

Sometimes the cancer causes fluid to collect around the lung or in the abdomen. These symptoms may be caused by the fluid or malignant mesothelioma. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

  • Trouble breathing.
  • Pain under the rib cage.
  • Pain or swelling in the abdomen.
  • Lumps in the abdomen.
  • Weight loss for no known reason.

Tests that examine the inside of the chest and abdomen are used to detect (find) and diagnose malignant mesothelioma.

Sometimes it is hard to tell the difference between malignant mesothelioma and lung cancer. The following tests and procedures may be used:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits, exposure to asbestos, past illnesses and treatments will also be taken.
  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
    • The number of red blood cells, white blood cells, and platelets.
    • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
    • The portion of the blood sample made up of red blood cells.
  • Sedimentation rate: A procedure in which a sample of blood is drawn and checked for the rate at which the red blood cells settle to the bottom of the test tube.
  • Biopsy: The removal of cells or tissues from the pleura or peritoneum so they can be viewed under a microscope by a pathologist to check for signs of cancer. Procedures used to collect the cells or tissues include the following:
    • Fine-needle (FNA) aspiration biopsy of the lung: The removal of tissue or fluid using a thin needle. An imaging procedure is used to locate the abnormal tissue or fluid in the lung. A small incision may be made in the skin where the biopsy needle is inserted into the abnormal tissue or fluid, and a sample is removed.
    • Thoracoscopy: An incision (cut) is made between two ribs and a thoracoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted into the chest.
    • Peritoneoscopy: An incision (cut) is made in the abdominal wall and a peritoneoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted into the abdomen.
    • Laparotomy: An incision (cut) is made in the wall of the abdomen to check the inside of the abdomen for signs of disease.
    • Thoracotomy: An incision (cut) is made between two ribs to check inside the chest for signs of disease.
  • Bronchoscopy: A procedure to look inside the trachea and large airways in the lung for abnormal areas. A bronchoscope is inserted through the nose or mouth into the trachea and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue samples, which are checked under a microscope for signs of cancer.
  • Cytologic exam: An exam of cells under a microscope (by a pathologist) to check for anything abnormal. For mesothelioma, fluid is taken from around the lungs or from the abdomen. A pathologist checks the cells in the fluid.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

  • The stage of the cancer.
  • The size of the tumor.
  • Whether the tumor can be removed completely by surgery.
  • The amount of fluid in the chest or abdomen.
  • The patient's age and general health, including lung and heart health.
  • The type of mesothelioma cancer cells and how they look under a microscope.
  • Whether the cancer has just been diagnosed or has recurred (come back).

After malignant mesothelioma has been diagnosed, tests are done to find out if cancer cells have spread to other parts of the body.

The process used to find out if cancer has spread outside the pleura or peritoneum is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the spread of the cancer in order to plan treatment. The following tests and procedures may be used in the staging process:

  • Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of the chest and abdomen, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
  • MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of the chest or abdomen. This procedure is also called nuclear magnetic resonance imaging (NMRI).
  • Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography. EUS may be used to guide fine-needle aspiration (FNA) biopsy of the lung, lymph nodes, or other areas.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The stages of malignant mesothelioma are divided into two groups.

Malignant mesothelioma stages are grouped into localized and advanced.

Localized malignant mesothelioma (stage I)

In localized malignant mesothelioma, cancer is found in the lining of the chest wall and may also be found in the lining of the lung, the lining of the diaphragm, or the lining of the sac that covers the heart on the same side of the chest.

Advanced malignant mesothelioma (stage II, stage III, and stage IV)

Advanced malignant mesothelioma includes stage II, stage III, and stage IV.

  • In stage II, cancer is found in the lining of the chest wall and the lymph nodes on the same side of the chest. Cancer may also be found in the lining of the lung, the lining of the diaphragm, or the lining of the sac that covers the heart on the same side of the chest.
  • In stage III, cancer has spread to any of the following areas:
    • The chest wall.
    • The mediastinum.
    • The heart.
    • Beyond the diaphragm.
    • The peritoneum.
    Cancer may have also spread to lymph nodes on the other side of the chest or outside the chest.
  • In stage IV, cancer has spread to distant organs or tissues.

Recurrent Malignant Mesothelioma

Recurrent malignant mesothelioma is cancer that has recurred (come back) after it has been treated. The cancer may come back in the chest or abdomen or in other parts of the body.

Cancer information from the NCI PDQ service