Summary

Key Points

• Malignant mesothelioma is a disease in which malignant (cancer) cells form in the lining of the chest or abdomen.
• Being exposed to asbestos can affect the risk of malignant mesothelioma.
• Signs and symptoms of malignant mesothelioma include shortness of breath and pain under the rib cage.
• Tests that examine the inside of the chest and abdomen are used to detect (find) and diagnose malignant mesothelioma.
• Certain factors affect prognosis (chance of recovery) and treatment options.

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). Malignant mesothelioma may also form in the heart or testicles, but this is rare.

Risk Factors

Being exposed to asbestos can affect the risk of 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. Talk to your doctor if you think you may be at risk.

Most 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. Living with a person who works near asbestos is also a risk factor for malignant mesothelioma.

Screening and Detection

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 in the chest and lung cancer.

The following tests and procedures may be used to diagnose malignant mesothelioma in the chest or peritoneum:

• 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, and 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.
• 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.
• 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.
  • Thoracotomy: An incision (cut) is made between two ribs to check inside the chest for signs of disease.
  • 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.
  • Open biopsy: A procedure in which an incision (cut) is made through the skin to expose and remove tissues to check for signs of disease.

The following tests may be done on the cells and tissue samples that are taken:

• • Cytologic exam: An exam of cells under a microscope to check for anything abnormal. For mesothelioma, fluid is taken from the chest or from the abdomen. A pathologist checks the fluid for signs of cancer.
  • Immunohistochemistry: A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
  • Electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under a high-powered microscope to look for certain changes in the cells. An electron microscope shows tiny details better than other types of microscopes.

Signs and Symptoms

Signs and symptoms of malignant mesothelioma include shortness of breath and pain under the rib cage.

Sometimes the cancer causes fluid to collect in the chest or in the abdomen. Signs and symptoms may be caused by the fluid, malignant mesothelioma, or other conditions. Check with your doctor if you have any of the following:

• Trouble breathing.
• Cough.
• Pain under the rib cage.
• Pain or swelling in the abdomen.
• Lumps in the abdomen.
• Constipation.
• Problems with blood clots (clots form when they shouldn’t).
• Weight loss for no known reason.
• Feeling very tired.

Treatment Options

There are different types of treatment for patients with malignant mesothelioma.

Different types of treatments are available for patients with malignant mesothelioma. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Three types of standard treatment are used:

Surgery

The following surgical treatments may be used for malignant mesothelioma in the chest:

• 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 therapy

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 chest or peritoneum, the drugs mainly affect cancer cells in those areas (regional chemotherapy). Combination chemotherapy is the use of more than one anticancer drug.

Hyperthermic intraperitoneal chemotherapy is used in the treatment of mesothelioma that has spread to the peritoneum (tissue that lines the abdomen and covers most of the organs in the abdomen). After the surgeon removes all the cancer that can be seen, a solution containing anticancer drugs is heated and pumped into and out of the abdomen to kill cancer cells that remain. Heating the anticancer drugs may kill more cancer cells.

The way the chemotherapy is given depends on the type and stage of the cancer being treated.

See Drugs Approved for Malignant Mesothelioma for more information.

New types of treatment are being tested in clinical trials.

This summary section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied. Information about clinical trials is available from the NCI website.

Biologic therapy

Biologic therapy is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to attack specific cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do. Monoclonal antibodies and kinase inhibitors are types of targeted therapies being studied in the treatment of malignant mesothelioma.

Monoclonal antibody therapy is a cancer treatment that uses antibodies made in the laboratory, from a single type of immune system cell. These antibodies can identify substances on cancer cells or normal substances that may help cancer cells grow. The antibodies attach to the substances and kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.

Kinase inhibitors are targeted therapy drugs that block signals needed for tumors to grow.

Patients may want to think about taking part in a clinical trial.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today’s standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI’s listing of clinical trials.

Follow-up tests may be needed.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.