Malignant Mesothelioma

Malignant mesothelioma is a rare form of cancer that begins in the tissue that surrounds different organs in the body called the mesothelium. Depending on the location in the body, the mesothelium has different names. The tissue that surrounds the lungs and lines the wall of the chest cavity it called the pleura. The tissue that covers organs in the abdominal cavity is called the peritoneum. The tissue that surrounds the heart is called the pericardium. The most common type of mesothelioma is pleural mesothelioma, which occurs in about three-fourths of all cases. Ten to twenty percent of the cases are peritoneal mesothelioma. Pericardial mesothelioma is extremely rare. Only about 2000 cases of mesothelioma are diagnosed per year in the United States and three to five time more men are affected than women (2).

Malignant mesothelioma is caused by the inhalation of asbestos. Asbestos is known for its use as insulation. It has been used in products such as cement, brake linings, roof shingles, textiles, and insulation. The fibers that make up asbestos are very fine and crystalline. When inhaled, the fibers go to the end of small airways and penetrate the lining of the lungs. The fibers then eventually cause a tumor to grow in the lung. If the fibers are swallowed, they infect the lining of the abdominal cavity. Symptoms of mesothelioma, however, may not be present until twenty to fifty years after the initial exposure to asbestos ( 7).

Symptoms of malignant mesothelioma may often be overlooked because they are easily mistaken as other, more common ailments. Symptoms of pleural mesothelioma include shortness of breath, chest pain, coughing, or pleural effusion (fluid that has accumulated between the lining of the lung and the chest cavity). Symptoms of peritoneal mesothelioma include abdominal pain, weight loss, nausea and vomiting (3).

Because the symptoms are similar to other ailments, diagnosing mesothelioma is difficult. A physical examination would have to be performed. The examination would include X-rays, a computed tomography (CT) scan or magnetic resonance imaging (MRI) (6). A biopsy is then performed if any of the tests show signs of mesothelioma. A biopsy is performed in different ways depending on the location of the cancer. In the case of pleural mesothelioma one common way is performing a thoracoscopy. A think tube called a thoracoscope is inserted into a small cut in the chest wall. The doctor can ten obtain tissue samples and see inside the chest. In the case of peritoneal mesothelioma the procedure is similar. The procedure is called a peritoneoscopy. A peritoneoscope is inserted into the abdomen to obtain tissue samples (4).

Once the biopsy is completed, the stage of the disease can then be measured. The stage is the “extent of spread” of the mesothelioma. The staging system is based on pleural mesothelioma mainly because it is the most common type. The staging system is called the Butchart system and consists of four stages. Stage I: The mesothelioma is present in the pleura. Stage II: The mesothelioma has spread to the chest wall, esophagus or heart. Stage III: The mesothelioma has spread to the diaphragm and into the peritoneum. Stage IV: The mesothelioma has possible spread to other organs. The staging system is very important because once the cancer is staged, the doctor knows which type of treatment to use (5).

The type of the treatment depends on the location and stage of the cancer and also depends on the patient’s age and health condition. Three types of treatment for malignant mesothelioma exist. Usually more than one treatment is used to increase the success rate. These treatments include surgery, chemotherapy and radiation therapy (3).

Surgery has different options. One type of surgery is a pleurectomy, which means that part of the chest or abdominal lining is removed. This surgery is used more for pain relief because even if the tumor is removed during the surgery, cancer can still be left along the lungs or diaphragm. Another type of surgery is a pneumonectomy, which means that an entire lung is removed or a part of the diaphragm is removed. Surgery is not used often though because it is believed that only one to five percent of patients are in good condition to undergo surgery (2).

Chemotherapy uses drugs to kill the cancer cells. It is usually given to the patient through an IV. The drugs given for chemotherapy are very toxic and have many different side effects. Some of the side effects include nausea, vomiting, weight loss, fatigue and hair loss. Sometimes the patient is given more than one drug at a time because using more than one drug has shown to be more effective in treating the mesothelioma. Less than twenty percent of patients respond well to being give only one drug at a time (4).

Radiation therapy is the use of high-energy rays to kill the cancer cells and shrink tumors. Radiation therapy is administered either by a machine or by putting materials that produce radiation through small tubes to the location of the cancer. Radiation therapy is usually used if the patient is too weak for surgery ( 3).

The treatments for mesothelioma are often not enough to control the disease even when they are combined. The survival rate for a person with malignant mesothelioma is approximately one year after diagnosis. If the cancer is diagnosed and treated early it is possible to increase the survival rate to two years or possible more (5).

Because mesothelioma is very difficult to diagnose and treat, cancer research centers are conducting clinical trials to help with this problem. One of these trials is intraoperative photodynamic therapy, which is the use of special drugs and light to kill cancer cells. Nine patients were involved in this trial. Two of them were successful, showing no symptoms of the disease. The other seven patients have since died from the disease. Although the survival rate with this treatment is low, it could help with future research (5).

Research and clinical trials are very important for patients who have malignant mesothelioma because often time they are not well enough to undergo many of the treatment options. As long as research and clinical trials are continued, treatments look to be promising to help extend the lives of patients with the disease.

Author: C. Parker and E. Neville

Title: Lung Cancer *8: management of malignant mesothelioma

Date of Article: September 2003

Journal: Thorax

Volume #: 58

Issue #: 9

Page #(s): 809(5)

Database: InfoTrac

Article #: A108266343

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Author: Dina Savastano

Title: Prolonging life for mesothelioma patients

Date of Article: March-April 1998

Journal: Radiologic Technology

Volume #: 69

Issue #: 4

Page #(s): 365(3)

Database: InfoTrac

Article #: A204470029

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Author: Alvin S. Teirstein

Title: Diagnosing malignant pleural mesothelioma

Date of Article: September 1998

Journal: Chest

Volume #: 114

Issue #: 3

Page #(s): 666(2)

Database: InfoTrac

Article #: A21195498

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Author: Barbara Apgar

Title: Diagnosis of Malignant Pleural Mesothelioma

Date of Article: January 15, 2000

Journal: American Family Physician

Volume #: 61

Issue #: 2

Page #(s): 536

Database: InfoTrac

Article #: A59486911

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Title: About Malignant Mesothelioma

Date of Article: 2003

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URL: http://mesothelioma-cancer-treatment.com

Website Name: Malignant Mesothelioma

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Title: Mesothelioma: Questions and Answers

Date of Article: May 13, 2003

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URL: http://cis.nci.gov/fact/6_36.htm

Website Name: National Cancer Institute

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Title: What is Mesothelioma?

Date of Article: 2001

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URL: http://www.mesothelioma-update.com/what.htm

Website Name: The Mesothelioma Online Information Resource