Mine waste containing asbestos was used to cover schoolyards and playgrounds in Wittenoom and an article published in the British Journal of Industrial Medicine in 1965 established that people who lived in neighbourhoods with asbestos factories & mines, but did not work in them had contracted mesothelioma just like those who had worked in the mines.

Inspite of proof that the dust from asbestos mines & mills causes asbestos related disease, mining still was started at Wittenoom in 1943 and continued there until 1966. The first time the dangers of blue asbestos were publicly announced was through a cover story in Australia’s Bullet magazine called “Is this killer in your home?” The Government of Western Australia in 1978 decided to phase out the town of Wittenoom, after the publication of a booklet “The Health Hazard at Wittenoom” by the Health Dept. which contained the results of air sampling and an overview of medical information on asbestos related diseases from all over the world.

The first writs alleging negligence related to Wittenoom were issued against CSR & its subsidiary ABA in 1979, and the Asbestos Diseases Society was formed to represent the victims of the Wittenoom mines.

Surgery

Surgery both itself as well as along with pre and post-operative therapies has also not worked well. Pleurectomy/decortication a procedure in which the lining of the chest is removed is the most common surgery. Another way is an extrapleural pneumonectomy (EPP) where the lung, the inner lining of the chest, the hemi-diaphragm and the pericardium are removed. It is however impossible to remove the mesothelium, keeping the patient alive.

Radiation

Radiation is given post operations to patients with localized disease and to those who can tolerate a radical surgery. The hemi-thorax is given radiation therapy, sometimes along with chemotherapy. Radiation along with chemotherapy has led to increases life expectancy and some patients have survived for more than 5 years. As a curative approach, radiotherapy is applied to the sites of the chest drain, in order to prevent the growth of the tumor along the track in the chest wall.

Although generally radiotherapy as a sole curative treatment does not work, palliative treatments routines are used to relive symptoms caused due to tumor growth. The dose of radiation that would be required to threat mesothelioma which has not been removed by surgery, would be very toxic.

Chemotherapy

The United States Food and Drug Administration approved pemetrexed as a drug to be used in the treatment of malignant pleural mesothelioma and is give along with cisplatin and folic acid to reduce its side effects.

Immunotherapy

http://www.tirgan.com/intrluk.htmImmunotherapy has also given variable results like intrapleural inoculation of Bacillus Calmette-Guerin while attempting to boost the immune response was of no use while in vitro lysis by LAK following activation by interleukin-2 was successful, though the patients experienced side effects. It was for this reason that trials have been suspended. Other trials with interferon alpha have had better results with more than 50% reduction in the tumor with minimal side effects for 20% of patients.

Heated Intraoperative Intraperitoneal Chemotherapy

Paul Sugarbaker of the Washington Cancer Institute developed as procedure called heated intraoperative intraperitoneal chemotherapy. In this the surgeon removes as much of the tumor as is possible through chemotherapy with the use of a chemotherapy agent in the abdomen.

Through this technique high concentration of selected drugs can be given in the abdominal and pelvic surfaces. Heating of the chemotherapy agent increases the chance of the drugs entering the tissue and there is greater chance of the malignant cells being destroyed due to heating than normal cells.

Contamination of the pleural cavity by asbestos and other mineral fibres has been known to lead to cancer. Among asbestos fibres, there are certain kinds which can be more potent to the human body. Long and thin fibres such as blue asbestos and amphibole fibres are more potent carcinogens as compared to what are known as “feathery fibres” such as chrysotile or white asbestos fibres. However in the recent past, studies have show that since smaller particles remain suspended in the air whereby they are inhaled and find their way into the lungs more easily, they are by far more dangerous that the longer variety. Dr. Alan Fein who is chief of pulmonary and critical-care medicine at the North Shore Long Island Jewish Health System, said following the World Trade Center attacks that due to the asbestos exposure to many patients from the collapsed buildings; a lot could be learnt about the various aspects of asbestos.

Some scientists believe that the transport of fibres to the pleura is critical to the pathogenesis of mesothelioma. This observation is backed by the increase of macrophages and other cells of the immune system in localized lesions of accumulated asbestos fibres in the pleural and peritoneal cavities of rats that were experimented upon.

During experiments it has been found that asbestos could be a carcinogen with the development of mesothelioma that occurs in the stages of initiation and promotion. The molecular mechanisms that cause normal mesothelial cell into malignant ones by asbestos fibres are still unknown even though its oncogenic capabilities are known. The complete in vitro change of normal mesothelial cells into malignant ones subsequent to asbestos exposure has not yet been achieved. It is believed that asbestos fibres directly interact with the cells of the mesothelium along with the other effects of interaction with inflammatory cells.

It has been shown through observing the reactions between asbestos fibres and DNA that phagocysted fibres make contact with chromosomes, getting attached to chromatin fibres or becoming entangled with the chromosome. Such interaction between the asbestos fibres and the chromosomes can cause severe abnormalities, the most common being the monosomy of chromosome 22 and the structural change of 1p,3p,9p and 6q chromosome arms.

Some gene abnormalities in mesothelioma cell lines are deletion of Neurofibromatosis type 2 at 22q12, P16^INK4A, P14^ARF which are tumor suppressor genes.

Asbestos is also known to control the entry of DNA into target cells and the entry of this foreign DNA may lead to complications, mutations and oncogenesis in the following ways including-

Inactivation of tumor suppressor genes

Activation of oncogenes

Activation of proto-oncogenes due to incorporation of foreign DNA

Activation of DNA repair enzymes which may be likely to cause errors

Activation of telomerase

Prevention of apoptosis

Asbestos fibres also have in the past altered the function and secretory properties of macrophages thereby creating conditions which lead to the development of mesothelioma. After asbestos phagocytosis an increased amount of hydroxyl radicals which could also be routine bi-products of cellular anaerobic metabolism. These free radicals are also clastogenic and membrane-active agents which are believed to promote asbestos carcinogenicity. These oxidants are capable of participating in the oncogenic process by directly and indirectly coming into contact with DNA, modifying membrane-related cellular events, including oncogene activation and disturbance of cellular antioxidant defences.

Asbestos in some cases may have immunosuppressive properties like chrysotile fibres are known to reduce the in vitro spread of phytohemagglutin-stimulated peripheral blood lymphytes, reduce natural killer cell lysis and decrease lymphokine-activated killer cell viability and recovery. Also, genetic changes in asbestos-activated macrophages could cause the release of deadly mesothelial cell mitogens such as platelet-derived growth factor and transforming growth factor- ? which may lead to the chronic stimulation and spread of mesothelial cells after injury due to asbestos fibres.

Asbestos also may possess immunosuppressive properties. For example, chrysotile fibres have been shown to depress the in vitro proliferation of phytohemagglutinin-stimulated peripheral blood lymphocytes, suppress natural killer cell lysis and significantly reduce lymphokine-activated killer cell viability and recovery. Furthermore, genetic alterations in asbestos-activated macrophages may result in the release of potent mesothelial cell mitogens such as platelet-derived growth factor (PDGF) and transforming growth factor-? (TGF-?) which in turn, may induce the chronic stimulation and proliferation of mesothelial cells after injury by asbestos fibres.

Another Australian activist Bernie Benton claimed compensation from James Hardie who contracted the disease while working. Steve McQueen died of a heart attack while in mexico a year after he was diagnosed with mesothelioma. His death occurred immediately after he was operated upon for cancer. Earlier he had been refused surgeryand chemotherapy because doctors were of the opinion that the cancer was too advanced. There have been some speculations as to how he came into contact with asbestos. McQueen had been serving with the US Marines when asbestos was commonly used as an insulator for pipers or when he was wokring in a shipyard during World War II. Another source of asbestos could have been racing suits where it was used as an insulator.

United States Congressman Bruce Vento died of mesothelioma in 2000 and his wife awards the The Bruce Vento Hopebuilder to persons and organizations that have supported mesothelioma research, in an annual function at the MARF symposium. Musician Warren Zoven died of a painful & untreated illness after he refused treatment fearing it would incapacitate him and concentrated his energies on wrapping up his final album before his death.

Even though the life expectancy with this disease is limited, there are quite a few notable people who have survived, including Stephen Jay Gould who was diagnosed with peritoneal mesothelioma in July of 1982 and wrote an article titled “The Median isn’t the Message for Discover magazine, wherein he argued that statistics were just abstractions that were useful and not destiny. He lived for another twenty years before finally succumbing to another disease, to metastatic adenocarcinoma of the lung.

Author Paul Kraus was found to have mesothelioma in 1997 after he underwent an umbilical hernia operation. Doctors gave him a few months but he is has survived using a variety of integrative & complementary methods and has written a book about his experiences with mesothelioma.

Approximately 27.5 million people were estimated to have been exposed to asbestos at work in the United States between 1940 and 1979 and between 1973 and 1984, the incidence of pleural mesothelioma has found to have increased threefold in Caucasian males. The casualties of Mesothelioma have increased by 50% from 2000 to 3000 per year in the U.S with men being four times more likely to acquire it than women. These figures however may not be entirely accurate since in many cases it is likely that mesothelioma has been mistakenly diagnosed as adenocarcinoman of the lung, which is similar and difficult to differentiate.

Risk factors

Constant contact with asbestos is a major risk factor for mesothelioma and exposure to asbestos is found in almost every reported case. However quite often, mesothelioma has also been reported in cases where there is no known exposure to asbestos. In sparingly few cases mesothelioma has also been found to have been caused by irradiation, intrapleural thorium dioxide and by inhaling other fibrous silicates such as erionite.

Asbetos is a group of minerals that occur naturally and in the form of masses of strong and flexible fibres that can be separated into thin threads and woven. It is this property of asbestos that makes it an oft-used material in industrial products such as cement, flooring products, textiles and for the purpose of insulation and in the form of brake linings and roof shingles. During the manufacturing process, tiny asbestos particles float in the air and such particles are liable to be swallowed or inhaled and can cause serious health hazards. In addition to causing mesothelioma, contact to asbestos can also increase the risk of lung cancer, asbestosis and cancers of the larynx and kidneys, among others.

Together smoking and exposure to asbestos can markedly increase the risk of a person developing cancer of the airways. Although by itself smoking cigarettes does not increase the risk of mesothelioma, a brand of cigarettes known as Kent was known to have used asbestos in its filters a few years in the 1950s and a few cases of mesothelioma were found to have been caused in persons who had smoked these cigarettes.

A few studies have lead to the belief that the simian virus 40 or SV40 may also play a contributing role in the development of mesothelioma.

Exposure

Though the properties of asbestos were known, it wasn’t until the late 1800s that the mining and commercial use of asbestos began. By the time of World War II it was used in great quantities and since the 1940s several million workers in America have been exposed to asbestos dust. However the risk of developing mesothelioma was first noticed among people who worked in shipyards, asbestos mines and mills and those who produced asbestos products and worked in heating and construction industries. The U.S Occupational Safety and Health Administration has set upper limits for asbestos exposure at the workplace and has laid down guidelines for engineering controls and respirators, putting up of warning signs, labeling, recordkeeping and the conducting of medical exams. The Health and Safety Executive (HSE), an initiative of the British Government however that made formal statements that the threshold for mesothelioma must be very low and that in case the threshold is very low, then it cannot be quantified at all. Therefore the assumption by the HSE is that a threshold does not exist at all. Thus people who come into contact with asbestos at work are required to wear protective gear to protect themselves from the risk of exposure.

Occupational

Since the beginning of the last century exposure to asbestos fibres has been regarded as and occupational hazard since it has been noted in various epidemiological studies that exposure to asbestos could be connected to the developing of lesions including asbestos bodies in the sputum, pleural plaques, diffusion of the pleural thickening and of mesothelioma of the pleura and peritoneum. Moreover asbestos has also been found to cause carcinoma of the lung and larynx.

The presence of asbestos fibred in food and water has given rise to concerns about the impact of long-term and in many cases unknown exposure of the population to asbestos. Though brief and transient exposure to these fibres has been considered to not be very harmful by many experts, some still believe that there is no known threshold of risk. People who have only breathed the air through air ventilation systems have been found to have mesothelioma as well as those who were direct exposure for a very minimal time period (3 months or less).

Between the years 1945 and 1966 commercial asbestos mining took place at Wittenoom in Western Australia. A longitudinal study of persons employed in the mine showed that while no deaths occurred within the first 10 years of crocidolite exposure, by 1985, 85 deaths and by 1994, 539 deaths caused due to mesothelioma had occurred.

Paraoccupational Secondary Exposure

The families of asbestos workers are at a much higher risk of developing asbestos related diseases since they are constantly exposed to asbestos dust which stays on the clothing and hair of an asbestos worker. To avoid exposing others to the risks of asbestos worker are requires to bathe and change their clothing prior to leaving the workplace.

Asbestos in buildings

Asbestos was used in building materials that was used to build both domestic as well as public premises prior to the banning of such material. People undertaking renovation or DIY activities are at a high risk of coming into contact with asbestos. The use of Chrysotile asbestos was banned in 1999 and brown and blue asbestos was banned around 1985 in the U.K. Buildings built or renovated prior to those dates however might have been built with asbestos containing materials.

Environmental Exposure

Mesothelioma has been found to occur at a higher rate among people living near areas with Naturally Occurring Asbestos or NOA.

Chrysotile and amphibole are the two major types of asbestos and it is believed that exposure to the amphibole has a higher risk of developing mesothelioma. But since chrysotile has been used more frequently, more mesothelioma is caused by this.

What are the long-term effects of the disease? Mesothelioma is a highly aggressive and potent tumour and the current treatment of it is such that the person is made comfortable. With the exception of Stephen Jay Gould, long-term survivors are not expected.

What are the risks to others? Mesothelioma is not contagious and after exposure to asbestos it takes many years and sometimes even decades before the disease can develop properly. People who live in close proximity with asbestos workers are at a higher risk of getting cancer.

What happens once treatment is over? Although mesothelioma is never very pleasant, a person should follow-up the treatment because further testing can detect relapses which may be even more dangerous.

Subsequent to the diagnosis a patient is placed in the Stage his symptoms are akin to among the following:

I. In the first stage cancer is localized or limited to a small area of the chest or abdomen.

II. In the second stage mesothelioma occurs in the mesothelium and also spreads to adjacent areas such as the lungs and diaphragm. This is known as advanced cancer.

III. Stage III mesothelioma is the same as Stage III, but is more advanced since the cancer has spread to lymph nodes in addition.

IV. When cancer has spread to other parts of the body including the brain it is known as Stage IV. This is the most advanced stage.

A physical examination is followed by chest X-ray and quite often by lung function tests. An X-ray may show pleural thickening which is quite common after exposure to asbestos and this finding further increases suspicion of mesothelioma. A CT (or CAT) scan or an MRI is usually performed. A process called cytology is performed whereby abnormal cells may be detected if a large amount of fluid is present, which is then aspirated with a syringe. The drainage of pleural fluid may be done with the help of a pleural tap or a chest drain, while a paracentesis or ascetic drain is used in ascites and a pericardiocentesis is resorted to in case of a pericardial effusion. If malignant cells are absent it makes the risk of (more…)