Mesothelioma

Malignant mesothelioma is a disease in which 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.

In this section, you can learn more about mesothelioma, including:

• The risk factors for developing mesothelioma
• The process of detecting and diagnosing mesothelioma
• Mesothelioma staging
• Treatment options for mesothelioma

Risk Factors for Mesothelioma

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 form.

Other risk factors for malignant mesothelioma include:

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

Detecting and Diagnosing Mesothelioma

Sometimes malignant mesothelioma 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 also cause the same symptoms. Check with your doctor if you have any of the following problems:

• Trouble breathing.
• Pain under the rib cage.
• Pain or swelling in the abdomen.
• Lumps in the abdomen.
• Weight loss for unknown reasons.

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: To check general signs of health, including 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 goes through the body, making a picture of areas inside the body onto film.
• Complete blood count (CBC): To draw a sample of blood to check 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 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:
  • Bronchoscopy: Looks 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: To examine 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.

Stages of Mesothelioma

The following stages are used for malignant mesothelioma:

Stage I (Localized)

Stage I is divided into Stages IA and IB:

• In Stage IA, cancer is found in one side of the chest in the lining of the chest wall and may also be found in the lining of the chest cavity between the lungs and/or the lining that covers the diaphragm. Cancer has not spread to the lining that covers the lung.
• In Stage IB, cancer is found in one side of the chest in the lining of the chest wall and the lining that covers the lung. Cancer may also be found in the lining of the chest cavity between the lungs and/or the lining that covers the diaphragm.

Stage II (Advanced)

In Stage II, cancer is found in one side of the chest in the lining of the chest wall, the lining of the chest cavity between the lungs, the lining that covers the diaphragm, and the lining that covers the lung. Also, cancer has spread into the diaphragm muscle and/or the lungs.

Stage III (Advanced)

Either of the following is true:

• Cancer is found in one side of the chest in the lining of the chest wall. Cancer may have spread to:
  • the lining of the chest cavity between the lungs;
  • the lining that covers the diaphragm;
  • the lining that covers the lung;
  • the diaphragm muscle;
  • the lung.
• Cancer has spread to lymph nodes where the lung joins the bronchus, along the trachea and esophagus, between the lung and diaphragm, or below the trachea.

or

• Cancer is found in one side of the chest in the lining of the chest wall, the lining of the chest cavity between the lungs, the lining that covers the diaphragm, and the lining that covers the lung. Cancer has spread into one or more of the following:
  • Tissue between the ribs and the lining of the chest wall
  • Fat in the cavity between the lungs
  • Soft tissues of the chest wall
  • Sac that covers the heart
• Cancer may have spread to lymph nodes where the lung joins the bronchus, along the trachea and esophagus, between the lung and diaphragm, or below the trachea.

Stage IV (Advanced)

In Stage IV, cancer cannot be removed by surgery and is found in one or both sides of the body. Cancer may have spread to lymph nodes anywhere in the chest or above the collarbone. Cancer has spread in one or more of the following ways:

• Through the diaphragm into the peritoneum (the thin layer of tissue that lines the abdomen and covers most of the organs in the abdomen).
• To the tissue lining the chest on the opposite side of the body as the tumor.
• To the chest wall and may be found in the rib.
• Into the organs in the center of the chest cavity.
• Into the spine.
• Into the sac around the heart or into the heart muscle.
• To distant parts of the body such as the brain, spine, thyroid, or prostate.

Mesothelioma Treatment Options

There are many options when it comes to treatment for Mesothelioma. The main three treatments are as follows:

Surgery

The following surgical treatments may be used for malignant mesothelioma:

• Wide local excision: Surgery to remove the cancer and some of the healthy tissue around it.
• Pleurectomy and decortication: Surgery to remove part of the covering of the lungs and lining of the chest and part of the outside surface of the lungs.
• Extrapleural pneumonectomy: Surgery to remove one whole lung and part of the lining of the chest, the diaphragm, and the lining of the sac around the heart.
• Pleurodesis: A surgical procedure that uses chemicals or drugs to make a scar in the space between the layers of the pleura. Fluid is first drained from the space using a catheter or chest tube and the chemical or drug is put into the space. The scarring stops the build-up of fluid in the pleural cavity.

Even if the doctor removes all the cancer that can be seen at the time of the surgery, some patients may be given chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.

Radiation

Radiation therapy is a cancer treatment that uses high-energy X-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy).

Combination chemotherapy is the use of more than one anticancer drug. The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Visit the National Cancer Institute where this information and more can be found about Mesothelioma or ask your cancer care team questions about your individual situation.