mardi 12 mars 2013

Mesothelioma

Mesothelioma is a rare form of cancer affecting the mesothelium, which is a membrane that covers and protects most of the internal organs of the body. In most cases, it begins in the pleura (the lining around the lungs) or peritoneum (the lining around the abdomen). The cancer is typically caused by asbestos exposure. A history of asbestos exposure at work is reported in about 70 to 80 percent of all cases of the disease. Standard treatment options include surgery, chemotherapy, and radiation therapy.

 


What Is Mesothelioma?

Mesothelioma is a benign (noncancerous) or malignant (cancerous) tumor affecting the mesothelium, which is a membrane that covers most of the body's internal organs. Most cases of mesothelioma begin in the pleura (lining around the lungs) or peritoneum (the lining around the abdomen).
Benign mesothelioma can also be called a fibroma, and cancerous mesothelioma is also known as malignant mesothelioma. A mesothelioma can further be named based on where it occurs. For example, malignant pleural mesothelioma is cancer that begins in the lining around the lungs.
Most people who develop malignant mesothelioma have worked on jobs where they inhaled asbestos particles. A benign mesothelioma does not appear to have any relationship to asbestos exposure.

Understanding the Mesothelium
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.
The mesothelium has different names, depending on its location in the body. The peritoneum is the mesothelial tissue that covers most of the organs in the abdominal cavity. The pleura is the membrane that surrounds the lungs and lines the wall of the chest cavity, while the pericardium covers and protects the heart. The mesothelial tissue surrounding the male internal reproductive organs is called the tunica vaginalis testis, and the tunica serosa uteri covers the internal reproductive organs in women.


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 to 80 percent of all cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos.
There is some evidence that family members and others living with asbestos workers have an increased risk of developing mesothelioma, and possibly other asbestos-related diseases. This risk may be the result of exposure to asbestos dust brought home on the clothing and hair of asbestos workers. To reduce the chance of exposing family members to asbestos fibers, asbestos workers are usually required to shower and change their clothing before leaving the workplace.
Smoking does not appear to increase the risk of mesothelioma. However, the combination of smoking and asbestos exposure significantly increases a person's risk of developing lung cancer (see Causes of Lung Cancer).

Mesothelioma and 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 mined and used commercially since the late 1800s; its use greatly increased during World War II. Asbestos has been widely used in many industrial products, including cement, brake linings, roof shingles, flooring products, textiles, and insulation. Since the early 1940s, millions of American workers have been exposed to asbestos dust.
If tiny asbestos particles float in the air, especially during the manufacturing process, they may be inhaled or swallowed and can cause serious health problems. In addition to mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous, chronic lung ailment), and other cancers, such as those of the larynx and kidney.
Initially, the risks associated with asbestos exposure were unknown. However, an increased risk of developing mesothelioma was later found among:
  • Shipyard workers
  • People who work in asbestos mines and mills
  • Producers of asbestos products
  • Workers in the heating and construction industries
  • Other tradespeople.
Today, the US Occupational Safety and Health Administration (OSHA) sets limits for acceptable levels of asbestos exposure in the workplace. People who work with asbestos wear personal protective equipment to lower their risk of exposure.
The risk of asbestos-related disease increases with heavier exposure to asbestos and longer exposure time. However, some individuals with only brief exposures have developed mesothelioma. On the other hand, not all workers who are heavily exposed develop asbestos-related diseases.

Symptoms and Diagnosis

For more about mesothelioma symptoms, click on the full eMedTV article about Mesothelioma Symptoms.
To find out more about making a mesothelioma diagnosis, click on the full eMedTV article about Mesothelioma Diagnosis.

How Is It Treated?

Treatment for mesothelioma depends on:
  • The location of the cancer
  • The stage of the disease
  • The patient's age and general health.
Standard mesothelioma treatment options include:
  • Surgery
  • Radiation therapy
  • Chemotherapy.
Sometimes, all three treatment methods are combined.

Statistics on Mesothelioma

Although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer. About 2,000 new cases of mesothelioma are diagnosed in the United States each year. Mesothelioma occurs more often in men than in women and risk increases with age, but mesothelioma can appear in either men or women at any age.
 Source : http://mesothelioma.emedtv.com/mesothelioma/mesothelioma.html

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