General Information about Malignant Mesothelioma

Malignant mesothelioma is a disease in which malignant (cancerous) 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 of the abdomen). Malignant mesothelioma can form in the heart or testicles, but this is not common

Exposure to asbestos can influence the risk of malignant mesothelioma.Anything that increases the risk of getting a disease is called a risk factor. Having a risk factor does not mean you are going to have cancer; Having no risk factors does not mean you will not have 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 exposure to asbestos, it usually takes a long time for a malignant mesothelioma to form. Living next to a person who works near asbestos is also a risk factor for malignant mesothelioma.

The signs and symptoms of malignant mesothelioma include shortness of breath and pain below the rib cage. Sometimes cancer causes fluid to build up in the chest or abdomen. Signs and symptoms can be caused by fluid, malignant mesothelioma or other conditions. Check with your doctor if you have any of the following symptoms:

•     Difficulty breathing.
•     Cough.
•     Pain below the rib cage.
•     Abdominal pain or inflammation of it
•     Nodules in the abdomen.
•     Constipation.
•     Problems with blood clots (clots that form when they should not).
•     Weight loss without known reason.
•     Feeling very tired. 

To detect (find) and diagnose malignant mesothelioma, tests are used to examine the inside of the chest and abdomen.

In some cases it is difficult to differentiate a malignant mesothelioma in the chest and a lung cancer.

To diagnose malignant mesothelioma of the chest or peritoneum, the following tests and procedures may be used:

• Physical examination and history: examination of the body to check general signs of health, including the control of signs of disease, such as masses or anything else that seems abnormal. It also takes the history of the patient's health habits, exposure to asbestos, and previous diseases and treatments.
•   X-ray of the thorax: X-ray of the organs and bones inside the thorax. An X ray is a type of energy beam that can go through the body and be reflected in a movie that shows an image of the inside of the body. 
• CT scan (CT scan): a procedure in which a series of detailed images of the chest and abdomen are taken from different angles. The images are created by a computer connected to an X-ray machine. A dye is injected into a vein or swallowed, so that the organs or tissues stand out more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. 
•  Biopsy: removal of cells or tissues from the pleura or peritoneum by a pathologist to observe under a microscope and determine if there are signs of cancer. The procedures used to collect cells or tissues are the following: 

• Fine needle aspiration biopsy (FNA) of the lung: extraction of tissue or fluid using a fine needle. An imaging procedure is used to locate abnormal tissue or fluid in the lung. A small incision can be made in the skin where the biopsy needle is inserted into the abnormal tissue or fluid, and a sample is removed.
• Thoracoscopy: A procedure in which an incision (cut) is made between two ribs and a thoracoscope (a thin, tube-shaped instrument with a light and a lens to be observed) is inserted into the chest.
•  Thoracotomy: incision (cut) made between two ribs to examine the inside of the chest and determine if there are signs of disease.
•  Peritoneoscopy: a procedure for which an incision (cut) is made in the abdominal wall and a peritoneoscope (a thin, tube-like instrument with a light and a lens to be observed) is inserted into the abdomen.
• Laparotomy: A procedure in which an incision (cut) is made in the wall of the abdomen to check for signs of disease inside the abdomen.
•  Open biopsy: A procedure in which an incision (cut) is made in the skin to expose and remove tissues to examine them for signs of disease.

The following tests can be performed on the samples of cells and tissues that are taken:

• Cytological examination: examination of cells under a microscope to determine if something is abnormal. In the case of mesothelioma, fluid is removed from the chest or abdomen. A pathologist checks these fluids for signs of cancer.
• Immunohistochemistry: A test for which antibodies are used to look for certain antigens in a tissue sample. The antibody usually binds to a radioactive substance or a dye that causes the tissue to glow under the microscope. This type of test can be used to establish the difference between different types of cancer.
• Electron microscopy: a laboratory test in which cells from a tissue sample are observed under a high power microscope in order to see changes in the cells. An electron microscope shows tiny details better than other types of microscopes.

Certain factors affect the prognosis (probability of recovery) and treatment options. The prognosis (probability of recovery) and treatment options depend on the following:

• The stage of cancer. 
• The size of the tumor
• If the tumor can be removed completely by surgery.
• The amount of fluid in the chest or abdomen.
• The age of the patient. 
• The degree of activity of the patient. 
• The general state of health of the patient, including the health of the lungs and the heart. 
• The type of mesothelioma cells and their appearance under a microscope.
• The number of white blood cells and the amount of hemoglobin in the blood. 
•  If the patient is male or female. 
•  If the cancer was recently diagnosed or relapsed (returned). 

Stages of malignant mesothelioma 

After diagnosing malignant mesothelioma, tests are done to determine if cancer cells have spread to other parts of the body.The process used to determine if cancer has spread outside the pleura or peritoneum is called staging. The information obtained in the staging process determines the stage of the disease. It is important to know if the cancer has spread and where to plan the treatment. In the staging process, the following tests and procedures can be used:

• CT scan (CT scan): a procedure in which a series of detailed images of the inside of the chest and abdomen are taken from different angles. The images are created by a computer connected to an x-ray machine. A dye is injected into a vein or swallowed so that the organs or tissues stand out more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• PET scan (scan with positron emission tomography): a procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and takes a picture of the places in the body that absorb glucose. Malignant tumor cells appear brighter in the image because they are more active and absorb more glucose than normal cells
• Endoscopic ultrasound (EE): procedure for which an endoscope is inserted into the body. An endoscope is a thin, tube-shaped instrument with a light and a lens to observe. A probe located at the end of the endoscope is used to bounce high-energy (ultrasonic) sound waves in tissues or internal organs and create echoes. The echoes form an image of the tissues of the body called the echogram. This procedure is also called endoechography. EUS can be used to guide the fine needle aspiration biopsy (FNA) of the lung, lymph nodes, or other areas.
• Pulmonary function test (PFT) -a test that is used to determine if the lungs are working well. It allows to measure the amount of air that the lungs can contain and the rapidity with which the air moves in and out of the lungs. It also measures the amount of oxygen that is used and the amount of carbon dioxide that is released during respiration. It is also called pulmonary functional test.

Cancer spreads in the body in three ways. Cancer can spread through the tissue, lymphatic system and blood: 
 

• Tissue. Cancer spreads from where it started and extends to nearby areas.
• Lymphatic system. Cancer spreads from where it started to enter the lymphatic system. The cancer travels through the lymphatic vessels to other parts of the body.
• Blood. Cancer spreads from where it started and enters the blood. The cancer travels through the blood vessels to other parts of the body. 

Cancer can spread from where it started to other parts of the body. When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they originated (primary tumor) and move through the lymphatic system or blood:

• Lymphatic system. The cancer penetrates the lymphatic system, travels through the lymphatic vessels, and forms a tumor (metastatic tumor) in another part of the body.
• Blood. Cancer penetrates the blood, travels through blood vessels, and forms a tumor (metastatic tumor) in another part of the body. 

The metastatic tumor is the same type of cancer as the primary tumor. For example, if malignant mesothelioma spreads to the brain, the cancer cells in the brain are, in reality, malignant mesothelioma cells. The disease is metastatic malignant mesothelioma, not brain cancer.The following stages are used for malignant mesothelioma: 

Stage I (located)

 Stage I is divided into stages IA and IB:
 

• In stage IA, the cancer is located on the side of the chest in the lining of the chest wall and can also be found in the lining of the chest cavity, between the lungs, or in the lining of the diaphragm. The cancer did not spread to the lining that covers the lung.
• In stage IB, cancer is found on one side of the chest in the lining of the chest wall and the lining of the lung. Cancer can also be found in the lining of the chest cavity between the lungs or in the lining of the diaphragm.
  

Stage II (advanced) 

In stage II, cancer is found on one side of the chest in the lining of the chest wall, the lining of the chest cavity between the lungs, the lining of the diaphragm, and the lining of the lung. In addition, the cancer has spread to one or both of the following sites: 
 

• Lung tissue 
• Diaphragm. 

Stage III (advanced)

In stage III, any of the following situations occur: Cancer is found on one side of the chest in the lining of the chest wall. The cancer may have spread to:

• The lining of the thoracic cavity between the lungs; 
• The lining that covers the diaphragm; 
• The lining that covers the lung; 
• The tissue of the lung; 
• The diaphragm; 

 The cancer has spread to the lymph nodes where the lung joins the bronchus, along the trachea and esophagus, between the lung and the diaphragm or below the trachea.

or 

Cancer is found on one side of the chest in the lining of the chest wall, the lining of the chest wall between the lungs, the lining of the diaphragm, and the lining that covers the lung. The cancer has spread to one or more of the following sites:

• The tissue between the ribs and the lining of the chest wall. 
• The fat of the area between the lungs. 
• The soft tissues of the chest wall. 
• The bag that surrounds the heart.

The cancer may have spread to the lymph nodes where the lung joins the bronchus, along the trachea and esophagus, between the lung and the diaphragm, or below the trachea.Stage IV (advanced)In stage IV, the cancer can not be removed by surgery and is found on one or both sides of the body. The cancer may have spread to the lymph nodes anywhere on the chest or above the clavicle. The 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 of the abdomen).
• The tissue that lines the chest on the opposite side of the body where the tumor is.
• To the thoracic wall and can be found in the rib.
• To the organs of the center of the thoracic cavity.
• To the vertebral spine.
• To the bag that surrounds the heart or to the heart muscle.
• To distant parts of the body such as the brain, vertebral spine, thyroid or prostate.

Recurrent Malignant Mesothelioma

 
Recurrent malignant mesothelioma is cancer that has recurred (come back) after it has been treated. Cancer can return to the chest, abdomen or other parts of the body. 

General aspects of treatment options

There are different types of treatment for malignant mesothelioma patients.

There are different types of treatment available for malignant mesothelioma patients. Some treatments are standard (the treatment currently used) and others are under evaluation in clinical trials. A clinical trial of treatment is a research study that seeks to improve current treatments or obtain information about new treatments for cancer patients. When clinical trials show that a new treatment is better than the standard treatment, the new treatment can become the standard treatment. Patients should think about participating in a clinical trial. Some clinical trials are open only for patients who have not started treatment.

Three types of standard treatment are used:

Surgery

The following surgical treatments can be used for malignant mesothelioma in the breast:

• Wide local excision: surgery to remove the cancer and some of the healthy tissue that surrounds it.
• Pleurectomy and decortication: surgery to remove a part of the lung cover and the lining of the chest, and part of the outer surface of the lungs.
• Extrapleural pneumonectomy: surgery to remove a whole lung and part of the lining of the chest, the diaphragm, and the lining of the sac that surrounds the heart.
• Pleurodesis: surgical procedure for which chemical substances or drugs are used to create a scar in the space between the layers of the pleura. First, the fluid is drained from the space with a catheter or chest tube, and the chemical or medication is placed in that space. The scarring stops the accumulation of fluid in the pleural cavity.