Pleural mesothelioma is cancer of the cells that make up the pleura, a membrane that lines the outside of the lungs and inside of the chest cavity.
Causes
Pleural mesothelioma is almost always caused by exposure to asbestos, a fibrous mineral that is known to cause cancer. Even people exposed to a small amount the dangerous form of asbestos fibers or those exposed for only a short time (a few weeks) may be at risk.
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition. The main risk factors for pleural mesothelioma are:
Symptoms
After being exposed to asbestos, it usually takes a long time (up to 20-40 years) for people to develop pleural mesothelioma. Early signs of pleural mesothelioma include:
Since the condition can develop gradually, many people with pleural mesothelioma have no symptoms for an extended period of time.
Diagnosis
Your doctor will first ask about your symptoms and medical history, and perform a physical exam. If your doctor suspects a mesothelioma, he or she may refer you to a doctor who specializes in lung problems (a pulmonologist) or cancer treatment (an oncologist).
Sometimes it is hard to tell the difference between pleural mesothelioma and other, more common types of lung cancer which are not caused by asbestos exposure. The following tests may be used to help diagnose which disease is present.
Blood Tests–including a complete blood count (CBC) and sedimentation rate (checks for the degree of inflammation within the body, which is often increased in the presence of cancer and other inflammatory conditions)
Chest X-ray–may show increased thickness of the pleural lining and/or excess fluid around the lungs
CT Scan (CAT Scan)–a type of x-ray that uses a computer to make pictures of structures inside the body; will show more detailed images of changes in the pleural lining
MRI (Magnetic Resonance Imaging)–a procedure that uses a magnet, radio waves, and a computer to make pictures of structures inside the body; use is similar to a CT scan
Biopsy–the removal of tissue from the pleura for evaluation under a microscope by a pathologist
These same tests and others may also be used to find out if cancer has spread outside the pleura. It is important to know whether and how far the cancer has spread to plan treatment. This step is called the staging process.
Treatment
Pleural mesothelioma is usually treated with chemotherapy, radiation, surgery, or a combination of these three treatments.
Prevention
The only known way to prevent pleural mesothelioma is to avoid asbestos exposure. People who could be exposed to asbestos at work include miners, factory workers, insulation workers, railroad workers, ship builders, makers of gas masks, and construction workers.
Family members of such workers have also developed mesothelioma because of fibers brought home on clothing. Although there is concern for asbestos exposure from building insulation (including older homes), roofing materials, and tiles, most of the household exposures have been in family members of individuals working with asbestos. This secondary exposure is just as dangerous as primary exposure and very common: about 10% of household contacts of those who work with asbestos will also show changes of asbestosis, the inflammatory and reactive changes that accompany significant asbestos exposure and precede the development of mesolthelioma.
The use of proper safety equipment and precautions can drastically reduce exposure in the workplace. To avoid exposing their families to asbestos, workers should also use approved safety measures so they do not bring asbestos dust home on their clothing.
Areas of exposed asbestos outside the workplace (eg, old public buildings and homes with asbestos shingles, tiles, or insulation) must be checked by experts, and these exposed areas must be removed by appropriate means or sealed off. A homeowner untrained in asbestos abatement should never attempt to remove asbestos material from a building.
RESOURCES:
American Lung Association
http://www.lungusa.org
National Cancer Institute
http://www.cancer.gov
CANADIAN RESOURCES:
Canadian Cancer Society
http://www.cancer.ca
Cancer Care Ontario
http://www.cancercare.on.ca
References:
American Lung Association website. Available at: http://www.lungusa.org/. Accessed August 2005.
Antunes G, Neville E, Duffy J, Ali N on behalf of the BTS Pleural Disease Group. BTS guidelines for the management of malignant pleural effusions. Thorax. 2003;58:ii29
Cugell DW, Kamp DW. Asbestos and the pleura: a review. Chest. 2004;125:1103-1117.
National Cancer Institute website. Available at: http://www.cancer.gov/. Accessed August 2005.
Nishimura SL, Broaddus VC. Asbestos-induced pleural disease. Clin Chest Med. 1998;19:311-329.
Roberts JR. Surgical treatment of mesothelioma: pleurectomy. Chest. 1999;116(6 Suppl):446S-449S.
