How common is mesothelioma?

Although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer. About 2,000 new cases of mesothelioma are diagnosed in the United States each year. Mesothelioma occurs more often in men than in women and risk increases with age, but this disease can appear in either men or women at any age.
What are the risk factors for mesothelioma?

Working with asbestos is the major risk factor for mesothelioma. A history of asbestos exposure at work is reported in about 70 percent to 80 percent of all cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos.
Asbestos is the name of a group of minerals that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven. Asbestos has been widely used in many industrial products, including cement, brake linings, roof shingles, flooring products, textiles, and insulation. If tiny asbestos particles float in the air, especially during the manufacturing process, they may be inhaled or swallowed, and can cause serious health problems. In addition to mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous, chronic lung ailment), and other cancers, such as those of the larynx and kidney.
Smoking does not appear to increase the risk of mesothelioma. However, the combination of smoking and asbestos exposure significantly increases a person's risk of developing cancer of the air passageways in the lung.
What are the symptoms of mesothelioma?

Symptoms of mesothelioma may not appear until 30 to 50 years after exposure to asbestos. Shortness of breath and pain in the chest due to an accumulation of fluid in the pleura are often symptoms of pleural mesothelioma. Symptoms of peritoneal mesothelioma include weight loss and abdominal pain and swelling due to a buildup of fluid in the abdomen. Other symptoms of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and fever. If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face.
These symptoms may be caused by mesothelioma or by other, less serious conditions. It is important to see a doctor about any of these symptoms. Only a doctor can make a diagnosis.
How is mesothelioma diagnosed?

Diagnosing mesothelioma is often difficult, because the symptoms are similar to those of a number of other conditions. Diagnosis begins with a review of the patient's medical history, including any history of asbestos exposure. A complete physical examination may be performed, including x-rays of the chest or abdomen and lung function tests. A CT (or CAT) scan or an MRI may also be useful. A CT scan is a series of detailed pictures of areas inside the body created by a computer linked to an x-ray machine. In an MRI, a powerful magnet linked to a computer is used to make detailed pictures of areas inside the body. These pictures are viewed on a monitor and can also be printed.
A biopsy is needed to confirm a diagnosis of mesothelioma. In a biopsy, a surgeon or a medical oncologist (a doctor who specializes in diagnosing and treating cancer) removes a sample of tissue for examination under a microscope by a pathologist. A biopsy may be done in different ways, depending on where the abnormal area is located. If the cancer is in the chest, the doctor may perform a thoracoscopy. In this procedure, the doctor makes a small cut through the chest wall and puts a thin, lighted tube called a thoracoscope into the chest between two ribs. Thoracoscopy allows the doctor to look inside the chest and obtain tissue samples. If the cancer is in the abdomen, the doctor may perform a peritoneoscopy. To obtain tissue for examination, the doctor makes a small opening in the abdomen and inserts a special instrument called a peritoneoscope into the abdominal cavity. If these procedures do not yield enough tissue, more extensive diagnostic surgery may be necessary.
If the diagnosis is mesothelioma, the doctor will want to learn the stage (or extent) of the disease. Staging involves more tests in a careful attempt to find out whether the cancer has spread and, if so, to which parts of the body. Knowing the stage of the disease helps the doctor plan treatment.
Mesothelioma is described as localized if the cancer is found only on the membrane surface where it originated. It is classified as advanced if it has spread beyond the original membrane surface to other parts of the body, such as the lymph nodes, lungs, chest wall, or abdominal organs.
What are the stages of mesothelioma?

Once malignant mesothelioma is found, more tests will be done to find out if cancer cells have spread to other parts of the body. This is called staging. A doctor needs to know the stage of the cancer to plan treatment. The following stages are used for malignant mesothelioma.
Localized malignant mesothelioma Stage I The cancer is found in the lining of the chest cavity near the lung and heart or in the diaphragm or the lung.
Advanced malignant mesothelioma Stage II The cancer has spread beyond the lining of the chest to lymph nodes in the chest.
Stage III Cancer has spread into the chest wall, center of the chest, heart, through the diaphragm, or abdominal lining, and in some cases into nearby lymph nodes.
Stage IV Cancer has spread to distant organs or tissues.
Recurrent malignant mesothelioma Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back in the lining of the chest or abdomen or in another part of the body.
How is mesothelioma treated?

Treatment for mesothelioma depends on the location of the cancer, the stage of the disease, and the patient's age and general health. Standard treatment options include surgery, radiation therapy, and chemotherapy. Sometimes, these treatments are combined.
Surgery is a common treatment for mesothelioma. The doctor may remove part of the lining of the chest or abdomen and some of the tissue around it. For cancer of the pleura (pleural mesothelioma), a lung may be removed in an operation called a pneumonectomy. Sometimes part of the diaphragm, the muscle below the lungs that helps with breathing, is also removed.
Radiation therapy, also called radiotherapy, involves the use of high-energy rays to kill cancer cells and shrink tumors. Radiation therapy affects the cancer cells only in the treated area. The radiation may come from a machine (external radiation) or from putting materials that produce radiation through thin plastic tubes into the area where the cancer cells are found (internal radiation therapy).
Chemotherapy is the use of anticancer drugs to kill cancer cells throughout the body. Most drugs used to treat mesothelioma are given by injection into a vein (intravenous, or IV). Doctors are also studying the effectiveness of putting chemotherapy directly into the chest or abdomen (intracavitary chemotherapy).
Intraoperative photodynamic therapy is a new type of treatment that uses special drugs and light to kill cancer cells during surgery. A drug that makes cancer cells more sensitive to light is injected into a vein several days before surgery. During surgery to remove as much of the cancer as possible, a special light is used to shine on the pleura. This treatment is being studied for early stages of mesothelioma in the chest.
To relieve symptoms and control pain, the doctor may use a needle or a thin tube to drain fluid that has built up in the chest or abdomen. The procedure for removing fluid from the chest is called thoracentesis. Removal of fluid from the abdomen is called paracentesis. Drugs may be given through a tube in the chest to prevent more fluid from accumulating. Radiation therapy and surgery may also be helpful in relieving symptoms.
What treatments are used at the different stagesof mesothelioma?

Treatment depends on where the cancer is, how far it has spread, and the patient's age and general health. Standard treatment may be considered because of its effectiveness in patients in past studies, or participation in a clinical trial may be considered. Not all patients are cured with standard therapy and some standard treatments may have more side effects than are desired. For these reasons, clinical trials are designed to find better ways to treat cancer patients and are based on the most up-to-date information. Clinical trials are ongoing in many parts of the country for many patients with malignant mesothelioma. To learn more about clinical trials, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.
Localized Malignant Mesothelioma (Stage I) If the cancer is only in one place in the chest or abdomen, treatment will probably be surgery to remove part of the pleura and some of the tissue around it.
If the cancer is found in a larger part of the pleura, treatment may be one of the following:
Surgery to remove the pleura and the tissue near it to relieve symptoms, with or without radiation therapy after surgery.
Surgery to remove sections of the pleura, the lung, part of the diaphragm, and part of the lining around the heart.
External beam radiation therapy to relieve symptoms.
A clinical trial of surgery followed by chemotherapy given inside the chest.
A clinical trial of surgery, radiation therapy, and/or chemotherapy.
Advanced Malignant Mesothelioma (Stages II, III, and IV) Treatment may be one of the following:
Draining of fluid in the chest or abdomen (thoracentesis or paracentesis) to reduce discomfort. Drugs also may be put into the chest or abdomen to prevent further collection of fluid.
Surgery to relieve symptoms.
Radiation therapy to relieve symptoms.
Chemotherapy.
A clinical trial of surgery, radiation therapy, and chemotherapy.
Chemotherapy given in the chest or abdomen.