Introduction
Asbestos refers to a mineral that is composed of fine fibres. Asbestos is classified into three main types. These include crocidolite asbestos, chrysotile asbestos and amosite asbestos. The first category is made up of asbestos that is white in colour while the second is made up of asbestos that is blue in colour. The last category of asbestos is brown in colour.
Apart from these main categories of asbestos, there are other minor types like anthophyllite, which refers to grey fibred asbestos (Early 2011). Asbestos fibres can enter the human body when a person inhales it. Some fibres subsequently get trapped within the body and end up causing diseases. Damages asbestos has loose fibre, which enter the lungs when breathed causing cancer.
Research has also shown that “long, thin fibres are more likely to be deposited deep in the lungs, while shorter, wider fibres are relatively less dangerous” (Fayed 2010, p. 1). Asbestos is a common phenomenon although it was banned some fourteen years ago. Almost everyone has therefore been exposed to it. This paper is an investigation into how asbestos causes cancer.
How asbestos causes cancer
Among the cancers caused by asbestos is mesothelioma, which is quite rare. In the UK, this cancer is found in approximately 3000 people per annum. Mesothelioma has been observed to occur in more men than women (National Cancer Institute 2009), which is because exposure to asbestos is more likely for men due to the nature of their work.
Abdominal mesothelioma also known as peritoneal mesothelioma is less common than pleural mesothelioma, which occurs in the chest. Asbestos is responsible for most cases of mesothelioma of the chest (pleural mesothelioma). The risk depends on the amount of asbestos one is exposed to and the length of the period during which one is exposed to asbestos.
Many cases of abdominal mesothelioma can also be attributed to exposure to asbestos (Rosen 2010). Additionally, mesothelioma can occur in the pericardium, the heart’s lining. This type is called pericardial mesothelioma (Early 2012).
Studies show that 90% of UK men with mesothelioma and 80% of UK women with mesothelioma “have been in contact with asbestos” (Cancer Research UK 2012). Asbestos may stay in an individual’s body for a period ranging between 15 and 60 years without causing mesothelioma (Cancer Research UK 2012). This is because after a person breathes in asbestos fibres, the fibres move to the lining of the lung, known as pleura.
Once there, they take years to irritate the pleura and cause mutations in the genes of the lung. It is only after these mutations that pleural mesothelioma can occur. In some cases, the irritation of the pleura makes the victim to develop a cough. As the patient coughs, he/she may swallow some of the inhaled fibres, moving them to the abdomen.
Once the fibres reach the abdomen, they may irritate the abdominal lining and cause mutations that may result in peritoneal mesothelioma (Cancer Research UK 2012). The same process takes place in the pericardium, causing mutation of the cells of the pericardium and eventually causing pericardium mesothelioma.
Some studies have shown that inhalation of asbestos can cause scarring of lungs, also known as asbestosis, colon cancer and throat cancer (Fayed 2010). As in the case of peritoneal mesothelioma, colon cancer is caused by asbestos when the inhaled fibres are coughed and swallowed by the victim.
After being swallowed, they move through the gut and get deposited in the colon, which is greatly folded. Once in the colon, the chemicals in the fibres cause irritation in the wall of the colon causing mutations. These mutations then lead to colon cancer. Asbestosis is caused by damaged pleura.
These pleura are destroyed by the chemicals in the asbestos fibres leading to death of cells that make up the pleura. Throat cancer is more likely to occur in individuals who, after exposure to asbestos, develop persistent coughs due to irritation of the lungs.
During this cough, some fibres are coughed up and thus they may get deposited in the throat, or scratch the throat leaving some chemicals. These chemicals may alter the genetic make-up of cells in the throat leading to mutations that cause throat cancer.
Other factors
Some other factors influence the development of cancer in people who have inhaled asbestos. One of these factors is the SV40 virus. Studies have indicated that if one is exposed to asbestos for some time and comes into contact with the aforementioned virus, he/she is more likely to develop mesothelioma than another person who is exposed to similar levels of asbestos without contracting the virus (Cancer Research UK 2012).
Despite the fact that the contribution of the virus to mesothelioma development is unclear, the virus is considered a possible co-factor in the development of mesothelioma. In some countries like Britain, polio vaccines were sometimes contaminated with the SV40 virus in the 1950s and 1960s (Cancer Research UK 2012).
Another factor considered a catalyst in development of cancer in asbestos-exposed individuals is radiation, especially from thorotrast, “a chemical used until the 1950s in some X-ray tests” (Cancer Research UK 2012). Studies show that peritoneal and pleural mesothelioma develops after thorotrast radiation exposure.
There has been conflicting evidence from studies on the effect of radiotherapy on the risk of developing mesothelioma. The conflicting evidence is a pointer to the possibility of negligible influence of radiotherapy on mesothelioma development (Cancer Research UK 2012).
Apart from the factors discussed above, risk of mesothelioma development is also increased by inhalation of paint chemicals while working as a painter. A mineral called erionite (mined in Turkey) is also a catalyst for development of mesothelioma.
Attributing cancer to asbestos
Majority of cancers of the lungs are caused by smoking of tobacco, but a small percentage of lung cancers can be attributed to exposure to asbestos (Agius 2011). Many of the latter cases are also associated to tobacco smoking. In some cases, it is important to identify if a certain case of lung cancer is due to asbestos or tobacco smoking.
For instance, in the United States, lung cancer victims can be compensated through litigation if it is established that the cancer is due to asbestos exposure in their places of work. It is also important to establish if cases of cancer are related to asbestos exposure in order to understand the extent to which asbestos is affecting public health (Agius 2011).
Studies have shown that people who are exposed to relatively high levels of asbestos, like industrial workers, have a higher risk of developing lung cancer. In this population, those who smoke tobacco are more likely to develop the cancer than their non-smoking counterparts.
Therefore, among the population exposed to asbestos, lung cancer will develop in more smokers than non-smokers. In industries, the minimum exposure for increased risk of developing lung cancer is “25 fibres per cubic centimetre year” (Cagle, 2002, p. 1). It has been estimated that this level of exposure can double the lung-cancer risk (Cagle, 2002, p. 1).
A study in Italy investigating the number of cancers attributable to asbestos revealed that 6% of the sample points had lung cancers that could be directly linked to asbestos exposure (Cagle, 2002, p. 1). These results indicate that the effect of asbestos to human health, especially development of cancers may be underestimated.
In the United States, 90% of all lung cancer incidences are attributed tobacco smoking. Second hand smoke also accounts for a considerable percentage of the remainder while asbestos exposure accounts for less than 5% (Cagle, 2002, p. 1).
Ignoring the contribution of asbestos to development of lung cancers can therefore be disastrous because in the 90% of cases explained by smoking, a considerable percentage also has asbestos as a secondary factor (Cagle, 2002, p. 1).
Recommendations
In order to limit exposure and minimize the chances of developing asbestos cancer, workers should avoid using all forms of asbestos (World Health Organization 2006). Asbestos materials should therefore be banned from being used. Workers should also be trained on asbestos in cases where asbestos materials have to be used. It is advisable to avoid using power tools.
Workers should use hand tools instead and keep materials damp. Workers should also ensure that they clean materials as they work on them using a vacuum cleaner. It is dangerous to use brushes for cleaning because brushes can increase the number of asbestos fibres circulating in the workshop.
Workers are also advised to wear special masks (different from dust masks) when working with asbestos materials (Asbestos and Lung Cancer 2011, Para. 15). To effectively avoid developing cancer due to asbestos exposure, workers should quit smoking tobacco because it has been shown to contribute to cancer development. That is, in case the worker smokes.
For those who do not smoke, the above preventive measures will be instrumental. In a nutshell, workers should avoid using materials that have asbestos. If asbestos has to be used, the works should be accomplished with strict preventive measures to avoid exposure to asbestos (World Health Organization 2006).
Conclusion
From the discussion above, it is evident that asbestos poses a health risk that cannot be ignored. Among the diseases that asbestos can cause include scarring of lungs, mesothelioma of the lungs, abdomen and the heart, colon cancer, throat cancer, etcetera.
People who have been exposed to high amounts of asbestos fibre over long periods of time are more likely to develop the aforementioned problems. Additionally, people who smoke tobacco and are exposed to considerable levels of asbestos have a greater risk of developing the aforementioned cancers and conditions.
There may be treatment for some of the conditions discussed above, but all the conditions lack a good prognosis. It is therefore vital to ensure that preventive measures are taken by workers who are at risk of coming in contact with asbestos. Workers should avoid working with asbestos or wear masks and avoid activities that may lead to significant exposure.
Reference List
Agius, R. 2011, Asbestos and Disease. Web.
Asbestos and Lung Cancer 2011. Web.
Cagle, P. 2002, Criteria for Attributing Lung Cancer to Asbestos Exposure. Web.
Cancer Research UK 2012, Mesothelioma risks and causes, Mesothelioma, Cancer Research UK, England. Web.
Early, J. 2011, Types of Asbestos. Web.
Early, J. 2012, Asbestos Cancer. Web.
Fayed, L. 2010, Being exposed to asbestos increases your cancer risk. Web.
National Cancer Institute 2009, Asbestos Exposure and Cancer Risk, Cancer. Web.
Rosen, G. 2010, Asbestos and Cancer Risk, Web.
World Health Organization 2006, Elimination of asbestos-related diseases, Public Health and the Environment, World Health Organization, Switzerland. Web.