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.
Anatomy of the respiratory system, showing the trachea and both lungs and their lobes and airways. Lymph nodes and the diaphragm are also shown. Oxygen is inhaled into the lungs and passes through the thin membranes of the alveoli and into the bloodstream (see inset).
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 doesnít 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 mesothelioma include the following:
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 patientís 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.
Bronchoscopy. A bronchoscope is inserted through the mouth, trachea, and major bronchi into the lung, to look for abnormal areas. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a cutting tool. Tissue samples may be taken to be checked under a microscope for signs of disease.
- 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).
Mesothelioma Treatment Options
There are different types of treatment for patients with malignant mesothelioma.
Different types of treatments 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:
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 increase the chances of a cure, is called adjuvant 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 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 spinal column, 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.
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 Web site.
Biologic therapy is a treatment that uses the patientís immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the bodyís natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.
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 mesothelioma 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 clinical trials database.
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. This is sometimes called re-staging.
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.
Source: National Cancer Institute