The only way to definitively diagnose mesothelioma is through analysis of tissue taken from the mesothelium through biopsy. The biopsy can be done by inserting a camera and surgical instruments through a small incision (thoracoscopy in the chest or laparoscopy in the abdomen) or by opening up the abdominal or chest cavity (thoracotomy or laparotomy). The tissue sample will be examined through a microscope to detect patterns that differentiate it from benign cells or other types of cancerous cells. If diagnosis is still unclear, tests for different chemicals in the cells or genetic testing of the cells may be needed, or an electron microscope can offer a closer look at the cells.

There are also benign (noncancerous) tumors of the mesothelium, and these are also called mesothelioma.

Types:
Pleural: The most common (75 percent). Of the mesothelial tissue surrounding the lungs and lining the chest wall.
Peritoneal: Second-most common (10-20 percent). Of the mesothelial tissue surrounding the abdominal organs.
Pericardial: Of the mesothelial tissue surrounding the heart. Rare.
Mesothelioma of the tunica vaginalis testis (in men) or and tunica serosa uteri (in women): Of the mesothelial tissue surrounding the male or female internal reproductive organs. Rare.

Chemotherapy: Palliative. Can be taken intravenously or intramuscularly, by mouth as a pill or locally injected into affected area.

Radiation: Palliative. Also used after surgery to avoid spreading mesothelioma to the incision site.

Combination therapy: Using surgery, chemotherapy and radiation, it is the most effective, but the most difficult; and in most cases the cancer will still return at some point.

Other theorized risk factors include exposure to simian virus 40 through old polio vaccines, radioactive thorium dioxide and the asbestos-like mineral zeolite.

Mesothelioma is relatively rare. About 2,000 to 3,000 people are diagnosed in the U.S. each year, but these rates seem to be going down. The average life expectancy after diagnosis is one year. The 5-year relative survival rate for mesothelioma is about 10 percent, but new treatments offered today may improve survival rates for those recently diagnosed.

Many asbestos producers began to pressure the U.S. government in preventing any asbestos laws that would restrict asbestos use because they feared the loss of profits. But by 1989, most products containing asbestos were banned.

Today, the EPA regulates the emission of asbestos from factories and also from building demolitions. OSHA also upholds asbestos laws limiting the amount of asbestos fibers found in the air and in the workplace. As a result of these regulations, many law firms are now set up to assist mesothelioma sufferers in processing claims to receive the compensation for which they are entitled.

• A surgical procedure called a pneumonectomy can be used for pleural mesothelioma, which involves the removal of the diseased lung. Depending upon the spread of the disease, this may also involve removing parts of the diaphragm, as well as the lung.

• Radiation is a commonly used method for treating mesothelioma and can be used along with surgery or alone if the patient is not well enough for surgery.

• Chemotherapy can be administered orally or as injected medication. However, these drugs can be highly toxic to healthy tissues and the side effects can make the patient extremely ill.

• In advanced stages of the disease, palliative therapies may be the treatment of choice. This may include draining excess fluids and providing comfort measures such as medications to ease the symptoms.

These tests are performed in one of two ways, depending upon the condition of the patient. A needle biopsy is a minimally invasive procedure in which cells from the affected area are abstracted through a hollow needle. A more precise test is to perform an “open biopsy”, in which a small piece of tissue is surgically removed for biopsy. After samples are sent to pathology, and if mesothelioma is present, it will then be determined if the disease is benign or malignant.

• Peritoneal Mesothelioma: This cancer may also affect the abdomen and symptoms include nausea and vomiting, abdominal pain, loss of appetite, bowel obstruction and fever.

• Pericardial Mesothelioma: This form of the disease affects the heart and the tissues surrounding it. Although this is the most rare variation of mesothelioma, the symptoms may include heart palpitations, chest pain, breathing difficulties and persistent coughing.

The symptoms of mesothelioma are very common to a number of many other diseases. For this reason, it is not unusual for the patient to be initially misdiagnosed. People who have worked with asbestos should inform their physician if they experience any symptoms because it is most important that a speedy diagnosis be made in order for treatment to be most effective.

Those most at risk in developing mesothelioma are people that have worked with asbestos over a period of 25 to 50 years. Due to the lack of protection and regulations during those years, these workers were constantly exposed to the dust and fibers from asbestos, which eventually caused the cells of the mesothelium to become abnormal.
Others at risk include family members who have had prolonged contact with asbestos workers because they carry the toxic material on their clothes, skin and hair.

•         T refers to whether the original tumor has exceeded its margins.

•         N stands for lymph nodes that are affected.

•         M refers to metastasis to other areas of the body.

Pleural mesothelioma is further divided into overall stages:

Stage I -The cancer is present only on the pleura of the chest wall and the outer lining of the lungs.

Stage II-The cancer has spread into the lining of the lung, the internal lung tissues, or the diaphragm.

Stage III-The cancer has invaded chest lymph nodes, or has not yet invaded lymph nodes but has spread to the mediastinum or the outer layer of the heart.

Stage IV-The cancer is present in adjacent structures, with or without spread to remote areas of the body.