Since doctors first found tumors on the lining of a
patient's lung in 1890, researchers have entertained several theories about
what causes pleural mesothelioma. It wasn't until 1960, however, that a
scientist named J.C. Wagner clearly attributed this cancer to asbestos
exposure.These genetic mutations affect cell division and cause mesothelioma tumors. Mesothelioma may take between 20-50 years to show symptoms. Symptoms are often mistaken as a common cold or pneumonia with chest pain, breathing discomfort, or a consistent cough.
The most recent consensus among medical professionals is that amphibole asbestos forms – in particular, crocidolite – are more potent than serpentine forms of asbestos, such as chrysotile. Even so, both forms of asbestos are highly carcinogenic. As the Environmental Protection Agency (EPA) has reported, there is no safe level of asbestos exposure, regardless of the type.
Mesothelioma is generally resistant to radiation and chemotherapy treatment. Long-term survival and cures are exceedingly rare. Treatment of malignant mesothelioma at earlier stages has a better prognosis. Clinical behavior of the malignancy is affected by several factors including the continuous mesothelial surface of the pleural cavity which favors local metastasis via exfoliated cells, invasion to underlying tissue and other organs within the pleural cavity, and the extremely long latency period between asbestos exposure and development of the disease. The histological subtype and the patient's age and health status also help predict prognosis. The epithelioid histology responds better to treatment and has a survival advantage over sarcomatoid histology.
Because of its extensive use, asbestos was handled daily by countless industrial and military workers. Anyone directly handling asbestos or working near it could have unknowingly breathed in asbestos fibers at work, inhaling them deep into their lungs, abdomen or heart linings.
More than 80% of mesothelioma cases are caused by exposure to asbestos. The greater the exposure the greater the risk. As of 2013 about 125 million people have been exposed to asbestos at work. High rates of disease occur in people who mine asbestos, produce products from asbestos, work with asbestos products, live with asbestos workers, or work in buildings containing asbestos. Asbestos exposure and the onset of cancer are generally separated by about 40 years. Washing the clothing of someone who worked with asbestos also increases the risk. Other risk factors include genetics and infection with the simian virus 40. The diagnosis may be suspected based on chest X-ray and CT scan findings, and is confirmed by either examining fluid produced by the cancer or by a tissue biopsy of the cancer.
An etiologic role for simian virus 40 in malignant mesothelioma has been suggested. However, although asbestos exposure alone has been associated with malignant mesothelioma, simian virus 40 alone has not. Thus, some epidemiologic evidence exists that simian virus 40 is a possible cocarcinogen. Its direct role at this point is still controversial.
Fast facts on mesothelioma: Here are some key points about mesothelioma. More detail is in the main article. Mesothelioma is an aggressive form of cancer that most commonly affects the lungs. It is most likely to result from exposure to asbestos, which may have been up to 30 years before symptoms appear. There is no cure, and treatment focuses on relieving symptoms and improving quality of life.
Mesothelioma is a rare form of cancer (malignancy) that most frequently arises from the cells lining the sacs of the chest (the pleura) or the abdomen (the peritoneum). Pleural mesothelioma is the most common form, often presenting with symptoms in the chest area. Peritoneal mesothelioma is much less common. This can affect the organs in the abdomen, and its symptoms are related to this area of the body, that is, abdominal swelling, nausea, vomiting, and bowel obstruction. The rarest form of mesothelioma is pericardial mesothelioma, which involves the sac surrounding the heart.
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