11/08/2007

Peritoneal Mesothelioma

Peritoneal Mesothelioma by http://www41.websamba.com/mesox

Mesothelioma Mesothelioma is a rare form of cancer that arises in the mesothelium. The mesothelium is made up of visceral and parietal membranes (thin layers of tissue), which surround organs and body cavities, such as the lungs or abdomen. The visceral membrane immediately surrounds the organ, and the parietal membrane is a sac covering the visceral membrane. There is a lubricating fluid between these membranes that make up the mesothelium. This fluid helps organs move easily among surrounding structures. In the case of the lung, it helps reduce friction between the lung and chest wall during normal breathing as the lung expands. There are different types of mesothelioma, depending where it is found in the body. In the abdomen, it is called peritoneal mesothelioma ; on the lungs, it is called pleural mesothelioma ; and if it develops on the heart, pericardial mesothelioma .

What causes mesothelioma?
Asbestos is a major known cause Studies show that asbestos is a major cause of mesothelioma. By various estimates, it accounts for about 75-80% of all mesothelioma cases in the United States . Asbestos is a mineral that occurs as a long, thin fiber in the environment. Before its usage was banned due to health dangers in the 1980s, it was used in many industrial and insulation materials as a fire retardant. Some of the jobs in which people have been exposed to asbestos directly or indirectly are those that involve factory work, demolition, insulation, shipbuilding, carpentry, and installation of brake linings in vehicles. Despite rigorous efforts to eliminate asbestos from our environment, some public and private buildings still contain asbestos.

Personnel who remove asbestos from such structures or work around asbestos are required to wear personal protective equipment to lower their risk of exposure. Asbestos fibers may be inhaled and become lodged in the lungs, which can cause damage. If swallowed, asbestos may lead to peritoneal mesothelioma. Scientists are still researching exactly how asbestos fibers cause mesothelioma. It may be by a direct action on the cells of the body or by forming substances that affect genes in the body.

There may be other causes Although asbestos is the major cause of mesothelioma, up to 30-50% of all cases are not obviously related to prior asbestos exposure. Other possible causes include prior exposure to radiation or to certain minerals closely related to asbestos that are found in the soil. Smoking has not been shown to be a cause of mesothelioma. However, if a smoker has also been exposed to asbestos, this greatly increases his or her risk of developing other types of lung cancer.

What are the facts about mesothelioma?
It takes a long time to develop Mesothelioma is characterized by having a long latency period, which means that symptoms don't develop for 20-50 years after environmental exposure. The average age at which symptoms usually begin to appear is around 60 years old. It is a relatively rare disease An estimated 2,000 to 3,000 cases of mesothelioma are diagnosed each year in the US . In other countries, the number of cases differs. Overall, the number of cases reported each year appears to be increasing. It occurs in men more than in women Mesothelioma affects men about three times more often than women in the US .

Incidence rises steadily with age. In other parts of the world, where exposure comes primarily from other environmental sources, such as in Turkey , mesothelioma occurs about equally in men and women. It develops mostly on the lungs The most common place for mesothelioma to develop is on the lungs. About two-thirds of all mesothelioma cases develop in the pleural mesothelium. This mesothelioma on the lungs is called malignant pleural mesothelioma (MPM). The remaining cases develop in the peritoneal mesothelium in the abdomen. A tumor in the abdominal mesothelium is called peritoneal mesothelioma. Rarely, mesothelioma occurs in other mesothelial tissue, such as on the heart or on the reproductive organs.

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