Of all people with intense and prolonged exposure to asbestos, 2 to 10% develop pleural mesothelioma. Symptoms of mesothelioma usually do not appear until 20-50 years after exposure to asbestos, which is when tumors have grown and spread. The average life expectancy of patients with mesothelioma is 12 to 22 months. Mesothelioma is caused by exposure to asbestos.
When asbestos fibers are inhaled or ingested, they cause scarring and inflammation, which can develop into a mesothelioma tumor. Research has shown that 80% of all cases of mesothelioma are caused by known exposure to asbestos. There are no other proven causes of mesothelioma. Researchers continue to investigate other possible causes and risk factors, such as exposure to the SV40 virus or minerals that look like asbestos.
Mesothelioma was practically unknown until the 20th century. Mesothelioma incidence rates increased as industries expanded the use of asbestos. The only proven cause of mesothelioma is exposure to asbestos. Most risk factors for mesothelioma involve different sources of exposure to asbestos.
Other risk factors, such as the genes you inherit or exposure to the simian virus 40, known as SV40, have not been shown to cause mesothelioma. Other potential risk factors that remain unproven causes of mesothelioma include genetic factors and exposure to radiation, zeolite minerals, and the polio vaccine between 1955 and 1963 that was contaminated with simian virus 40 (SV40). Asbestos fibers take an average of 20 to 50 years to convert normal mesothelial cells into mesothelioma cancer cells. This time lag between exposure and the development of the disease is known as the latency period.
Asbestos fibers take decades to cause damage that leads to mesothelioma, but once mesothelial cells become cancerous, they can quickly form mesothelioma tumors that grow and spread within months to a few years. According to the American Cancer Society, 80% of mesothelioma cases are caused by known exposure to asbestos. Studies have shown that radiation treatment for other types of cancer or certain genetic markers may increase the risk of developing mesothelioma. However, asbestos is still the only proven cause of the disease.Short-term exposure to asbestos dust can cause mesothelioma and other forms of cancer.
However, unless the exposure is intense, the risk of cancer from short-term exposure is very low. The main risk factor for pleural mesothelioma is exposure to asbestos. In fact, most cases of pleural mesothelioma have been linked to high levels of exposure to asbestos, usually in the workplace.Asbestos is a well-established cause of mesothelioma and lung cancer. It is generally accepted that the risk of mesothelioma persists and increases long after exposure to asbestos has ended.
Less is known if the risk of lung cancer changes when exposure to asbestos ceases. Some studies indicate that the risk decreases some years after exposure has ended. The results of studies based on industrial cohorts are difficult to assess because workers may have been exposed in other industries after leaving the industry because the use of asbestos has been common in many industries, for example, the construction industry and the shipyard industry.The risk of asbestos was highlighted in Sweden in the 1970s, and the import of asbestos fell dramatically (Fig.). Some industries, such as the shipyard and construction industry, decreased the use of asbestos in the mid-1970s following agreements between employers and unions.
A law banned the use of asbestos in 1982.Subsequently, the exhibition of almost all Swedish workers ended in the early 1980s. This provides an opportunity to study the risk of lung cancer after cessation of exposure.Even if a Swedish worker changed jobs and employers after the early 1980s, there was almost no exposure to asbestos. We know that asbestos causes most cases of pleural mesothelioma. This starts in the two sheets of tissue that cover the lungs, called the pleura.
Being exposed to large amounts of asbestos for a long period of time increases the risk of mesothelioma. Many people with mesothelioma in the abdomen (peritoneal mesothelioma) have also been exposed to asbestos.The link between mesothelioma and asbestos was found in the 1960s. This is due to the intensive use of asbestos in industry since the end of the Second World War until the mid-1970s. However, some people with mesothelioma say they have no history of exposure to asbestos.There are 3 main types of asbestos: blue, brown and white.
Blue and brown asbestos is strongly related to mesothelioma. It is now also thought that white asbestos is harmful. Asbestos is made up of tiny fibers. You can inhale these fibers when it comes into contact with asbestos.There is some evidence that families of people exposed to asbestos are at increased risk of developing mesothelioma.
This is because you can wear asbestos fibers home in your clothes. Smoking also increases the risk of cancer in people who have been exposed to asbestos.Mesothelioma may not develop until 15 to 60 years after you've been exposed to asbestos. That is why we have seen an increase in cases in recent years.If you worked as a painter, you could have a higher risk of mesothelioma. This is because until the 1990s some paintings contained asbestos.
You may also have been exposed to asbestos in workplaces.In Turkey, an asbestos-like mineral called erionite has been shown to increase the risk of mesothelioma. But this hasn't been found anywhere else.Because asbestos was used in the construction of the North Tower of the WTC, when the building was attacked, hundreds of tons of asbestos were released into the atmosphere.The time exponent was greater for peritoneal mesothelioma (3.2) than for pleural mesothelioma (2.8) (table). When asbestos fibers move to different parts of the body, they can cause different types of mesothelioma.Conclusions Exposure to asbestos confers a long-term risk of developing pleural and peritoneal mesothelioma, which increases after cessation of exposure.Mesothelioma doctors will order CT scans and other tests based on your medical history and symptoms.