Mesothelioma Cancer Basics
Mesothelioma is a relatively rare form of cancer that affects the mesothelium (a membrane that covers and protects most of the internal organs of the body). As a form of cancer, mesothelioma is a disease that causes the cells of the mesothelium to become abnormal and divide without control or order. Such 'malignant' cells can invade and damage nearby tissues and organs. These cancer cells can also spread from their original site to other parts of the body (a process called metastasis).
Most mesotheliomas begin in the tissues lining the lungs (called the pleura). In fact there are two pleural membranes (an inner and an outer) exude a fluid into the space between them which allows the membranes to move smoothly over one another as the lungs expand and contract with normal breathing. However, as the pleura of the lungs are so close to the heart mesothelioma can also affect the tissue lining of the heart itself, the pericardium. The pericardium performs much the same function for the heart as the pleural membranes do for the lungs.
The other form of mesothelioma affects the tissue lining of the abdominal cavity, the peritoneum. Again, this is a pair of membranes with a fluid lubricant between them that allows the contents of the abdomen (liver, stomach, intestines) to move smoothly inside the abdomen as we walk around. The form of mesothelioma that affects the tissues lining the abdominal cavity is called peritoneal mesothelioma. Generally it is unusual for mesothelioma to spread to other parts of the body. But if it does, it does not usually cause troublesome symptoms.
There is a third form of mesothelioma, known as benign mesothelioma that is non-cancerous and generally develops in the pleura (the lining of the lungs) or in the lining of the reproductive organs (testes or ovaries). However, this non-cancerous form of mesothelioma is extremely rare in incidence.
Incidence of Mesothelioma
Although a rare form of cancer, mesothelioma is on the increase, mostly due to environmental factors. In general there are four times as many cases in men as in women. This predominantly due to the main cause of mesothelioma, which is almost entirely caused by exposure to asbestos (although there may be other causes). Unfortunately the number of cases of mesothelioma in the developed world are expected to rise sharply over the next 20 years due to the heavy use of asbestos in industry in the years immediately following the second world war.
Indeed, almost 80% of those diagnosed with mesothelioma say that they have been in contact with asbestos. The risk is also greater if the affected person was exposed to a large amount of asbestos from an early age or if exposure lasted for a long period of time.
Asbestos and Mesothelioma
Unlike almost all other forms of cancer, the causes of mesothelioma are almost entirely known. With the predominant factor being exposure to asbestos.
Asbestos itself is a fire-resistant compound composed of many tiny fibres. Unfortunately these can easily break away from the main bulk of the material and are easily breathed in through the mouth and the nose. Being needle-like entities these tiny fibres can fairly easily work their ways into the pleura lining the lungs. They irritate these membranes and damage the cells that these pleura are composed of. Some of these fibres can also be coughed up and swallowed and this is what probably causes peritoneal mesothelioma.