Exposure to asbestos is the major risk factor for the development of mesothelioma. The first association between asbestos and cancer was established in 1955 in a case-Control study, appearing in 1960 related data that also pleural mesothelioma. As discussed in previous chapters, there are two types of asbestos fibers, the “curvilinear” (chrysotile) and “straight” (crocidolite), the latter being primarily involved in tumor pathogenesis are being transported to the periphery of the lung and contact with the pleural surface, while the former remain in the central airways and are eliminated more easily. The latency period between initial exposure and death varies widely, with an average of 48 years.

Numerous epidemiological studies have demonstrated the relationship between exposure to asbestos and mesothelioma as well as its development after the intrapleural instillation or inhalation of asbestos fibers. However, although 80% of patients have a history of exposure to asbestos, only 10% of those exposed developed mesotelioma which suggests the existence of other associated factors among which highlights the role given to the simian virus SV- 40 as a cofactor in the pathogenesis of mesothelioma after checking the expression of viral sequence animales8 models. Some chromosomal abnormalities and deletions of regions 1q, 3p, 9p and 6q chromosome 22 have also been cited in the pathogenesis of mesothelioma.

Antman and col9 and col10 Roviaro and have found no relationship between the existence of prior radiation and presence of calcification postuberculosa, respectively, with cases of mesothelioma. There is no definitive evidence that snuff increases the risk of developing the disease.

Asbestos mainly affects the lungs and lining of the lungs, the pleura. Asbestos causes two main types of diseases: cancer and asbestosis.

Asbestosis

Breathing high levels of asbestos fibers have long or short exposure to high levels of asbestos can cause scarring lesions that appear in the lung and pleura. This disease is called asbestosis, lung was the first disease that was associated with asbestos and can cause disability and death.

It is defined as diffuse interstitial fibrosis of the lungs resulting from exposure to asbestos dust and, therefore, commonly occurs in workers exposed to asbestos. People with asbestosis because of the scars in the lungs, difficulty breathing, often a cough, and in severe cases suffer enlarged heart.

Breathing low levels of asbestos can cause alterations in the pleura, generating so-called “plaques”. Pleural plaques can occur in workers and occasionally in people who live in areas with high environmental levels of asbestos. The effects of pleural plaques on respiration are not usually serious, but exposure to higher levels can cause a thickening of the pleura which may restrict breathing.

Cancer

The Department of Health and Human Services (DHHS), the World Health Organization (WHO / WHO) and the EPA (Environmental Protection Agency – EPA) EE. UU. have determined that asbestos is carcinogenic to humans.

It is known that breathing asbestos can increase the risk of cancer in humans. There are two types of cancer caused by exposure to asbestos: lung cancer and mesothelioma.
The first reports linking lung cancer and asbestos date back to 1935. The cancer caused by asbestos is not immediately apparent but emerges after several years (pleural mesothelioma usually has a latency period of 20 to 40 years). Studies of workers also suggest that breathing asbestos can increase the chances of getting cancer in other body parts (stomach, larynx, intestines, esophagus, pancreas and kidneys). The early identification and treatment of all cancer can increase the quality of life and survival of the individual.

Common symptoms are loss of appetite and weight, fatigue, chest pain, hemoptysis, or coughing up blood and shortness of breath.

It was suggested that the combination of exposure to asbestos and cigarette smoke significantly increases the chances of contracting lung cancer. Although this combination is considered to asbestos as the main cause of death, up from smoking. Generally production companies are hiding, even today, consider the potential impact of smoking on cancer development, since most of the manufacturing population were smokers at times of peak use of asbestos. Several court decisions have ruled out, depending on levels of exposure that the incidence of smoking is higher than that of asbestos for the development of occupational cancer.

Lots of deaths from cancer, previously diagnosed as being due only to lung cancers are currently considered caused by asbestos, but only if done correctly autopsy of the deceased, so that relevant statistics are not entirely reliable.

There is controversy about whether chrysotile is carcinogenic potency higher or lower than other varieties of asbestos.

Malignant mesothelioma caused by exposure to asbestos, a mineral that was commonly used as building material-is often incurable.

But some experts thought that chemotherapy could help prolong patients’ lives and improve their quality of life.

However, new research published in the medical journal The Lancet, found no benefit with this treatment.

Exhibition

Asbestos is a group of minerals that occur naturally in the environment. Due to its characteristics of strength and flexibility, this material was commonly used in various applications, mainly in construction.

However, when breathed, asbestos fibers can lodge and accumulate in the lungs and cause injuries and diseases such as mesothelioma.

Currently there are laws around the world to control the use of asbestos, but thousands of people die each year because the symptoms can appear up to 50 years after exposure.

According to experts, these decades of delay between exposure and onset of the disease means that cases continue to rise over the next five years.

The study, conducted by the Medical Research Council UK, analyzed the cases of 409 patients, mainly in the country which had received the standard treatment for mesothelioma.

This usually includes steroid drugs and radiotherapy sessions. Some patients in study received additional doses of chemotherapy to compare the effect of his illness.

Real benefit

According to the researchers, patients who received chemotherapy lived an average of slightly more than those who received standard treatment.

But this, scientists say, not a statistical test and can be misleading.
Moreover, they add, chemotherapy did not improve quality of life of these patients.

“Thousands of people are or will be affected by this deadly disease, and our study shows how difficult it is to treat mesothelioma,” said Dr Richard Stephens from the Medical Research Council.

“This is mainly because mesothelioma forms in the pleura, the lung lining layer, which is very difficult to achieve,” he adds.

The results of the study, the researchers explain, show that you get no real benefit in the treatment of disease symptoms when added to standard chemotherapy drugs.

It is known that chemotherapy also have serious effects.