What is mesothelioma?

Mesothelioma is a rare form of cancer in which malignant (cancerous) cells are found in the mesothelium, a protective sac that covers most of the body's internal organs," states the web site of National Cancer Institute (NCI).

Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles. "The mesothelium is a membrane that covers and protects most of the internal organs of the body. It is composed of two layers of cells: one layer immediately surrounds the organ; the other forms a sac around it."

"The mesothelium produces a lubricating fluid that is released between these layers, allowing moving organs (such as the beating heart and the expanding and contracting lungs) to glide easily against adjacent structures."

How common is mesothelioma?

The National Cancer Institute says that "although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer." However, according to cancer.gov there are about 2,000 new cases of mesothelioma diagnosed in the United States each year. The statistics show that mesothelioma is more likely to occur in men than in women and risk increases with age. However, this does not women are 'immune' to the disease. According to NCI the "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.

What is 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 (click here for more details about materials containing asbestos).

If tiny asbestos particles float in the air, especially during the manufacturing process, they may be inhaled or swallowed. This leads to serious health problems.

Does smoking increase the risk?

According to NCI smoking does not appear to increase the risk of mesothelioma. However, the Institue adds, "the combination of smoking and asbestos exposure significantly increases a person's risk of developing cancer of the air passageways in the lung."