Mesothelioma cancer (asbestos) Asbestos and cancer April 06 2021
Jenny Boss Jenny Boss Health Writer

You might have heard asbestos is dangerous, but what is it and what health problems can it cause?

What is asbestos?

Asbestos is a group of naturally occurring toxic minerals. It was commonly used throughout the 20th century in thousands of products and many industries. Asbestos is naturally resistant to heat and fire, making it ideal for use in insulation. The fine, flexible fibres that make up asbestos were frequently mixed with cement and woven into fabrics.

Why is asbestos a problem?

Exposure to asbestos fibres can result in the development of serious illnesses such as malignant mesothelioma, lung cancer and asbestosis. Hundreds of Australians die each year due to asbestos-related illnesses. Australia has the second highest rate of asbestos-related cancer deaths in the world.

Asbestos was phased out in Australia during the 1980s and it was ultimately banned from building products in 1989, though it remained in car gaskets and brake linings until recently. Asbestos was prohibited completely after 31 December 2003.

Who is most at risk of asbestos exposure?

Exposure to asbestos occurred frequently on the job in many different occupations. It was often prevalent in asbestos mines and the processing and manufacturing plants where asbestos products were produced.

From 1945 until the mid-1980s, those working in the construction industry were likely to have been exposed to asbestos. Many public buildings built during this period, as well as around a third of private dwellings, used building materials that contained asbestos. This included concrete, cement sheeting, vinyl floor coverings, pipes and boilers, and insulation.

Shipyards, oil refineries, power and chemical plants were also common exposure sites. Those who worked in certain occupations such as firefighters, auto mechanics and machinists may have been frequently exposed to asbestos.

People who haven’t worked directly with asbestos could also have been exposed to it, such as anyone cleaning work clothes with asbestos fibres on them, or people disturbing asbestos during home renovations or maintenance.

Those who work to remove asbestos or deal with asbestos that remains at certain sites are also at risk of exposure and have to take careful precautions against the consequences of uncontrolled, unsafe removal.

What cancers are caused by asbestos exposure?

Asbestos exposure has been linked to the development of several cancers, including mesothelioma and lung cancer. Exposure has also been linked to cancer of the ovary and larynx, and there is limited evidence that it may increase the risk of stomach, pharynx and colon cancer.

Asbestosis is a progressive pulmonary (lung) disease that is also caused by asbestos exposure. Conditions such as pleural plaques, chronic obstructive pulmonary disease and interstitial lung disease are among other illnesses associated with asbestos exposure.

What is mesothelioma?

Each year in Australia, between 700 and 800 people are diagnosed with mesothelioma. Mesothelioma is a rare and aggressive cancer that develops in the mesothelium, a protective membrane that lines several areas of the body. The only known cause of mesothelioma is asbestos exposure.

In 2018, 699 Australians died of mesothelioma. The majority of those individuals were men (569), probably because more men were exposed to asbestos at work. More than 70 percent of mesothelioma deaths are among men and women over the age of 65.

What are the different types of mesothelioma?

The four different types of mesothelioma are named for the area of the body they affect.

  • The most common type is pleural mesothelioma, which accounts for over 90% of all mesotheliomas. It develops in the mesothelial lining of the lungs, known as the pleura.
  • Peritoneal mesothelioma occurs in the peritoneum, the lining of the abdominal cavity.
  • Pericardial mesothelioma affects the membrane surrounding the heart, known as the pericardium.
  • Testicular mesothelioma develops in the tunica vaginalis, the lining around the testicles.
Diagram of body with Mesothelioma

How does mesothelioma develop?

The cancer develops when asbestos fibres are inhaled or ingested into the body where they can become lodged in organs or cavities, causing inflammation and scarring. This can damage the cells’ DNA, causing changes that result in uncontrolled cell growth that leads to cancer. When mesothelioma develops in the pleura, the layers of the pleura thicken and may press on the lung, preventing it from expanding when breathing in.

What are the symptoms of mesothelioma?

A mesothelioma patient may not notice any symptoms of mesothelioma until 20 to 50 years after initial exposure to asbestos. Symptoms often resemble illnesses such as influenza and pneumonia, and in the case of pericardial mesothelioma, symptoms can resemble other cardiac conditions. This can make diagnosis difficult though informing a doctor of prior asbestos exposure can alert them of the possibility of an asbestos-related disease.

Patients with pleural mesothelioma may experience symptoms including shortness of breath, persistent raspy cough, difficulty swallowing, night sweats, fatigue and chest pain. Symptoms expressed by a peritoneal mesothelioma patient include diarrhea or constipation, nausea, fever, swelling or pain in the abdomen and anaemia. Pericardial mesothelioma patients may experience chest pain, heart palpitations, difficulty breathing, fever and fatigue. The only known symptom of testicular mesothelioma is the appearance of testicular lumps.

What is the typical prognosis for a patient with mesothelioma?

Since a mesothelioma diagnosis often occurs once the cancer has progressed to later stages of development, prognosis (the probable outcome due to a disease) is typically poor. Since 1986, the 5-year relative survival rate has remained at around 5.5%.

However, if a patient is diagnosed before the cancer has spread or elects to undergo treatment to combat the cancer, their prognosis may improve. Factors that may influence prognosis include: the stage of a patient’s mesothelioma at the time of diagnosis, type of mesothelioma, size of the tumour, location of the tumour and whether it may be surgically removed, and the age and overall health of the patient.

Is there a cure for mesothelioma?

While a cure for mesothelioma doesn’t currently exist, treatment options such as surgery, chemotherapy and radiation are available for patients to help combat the cancer. Extensive studies and clinical trials are in progress internationally and cancer specialists and doctors are constantly working towards the discovery of a cure.

Further information

Asbestos Diseases Research Institute
www.adri.org.au

Australian Mesothelioma Registry
www.mesothelioma-australia.com  

The Mesothelioma Center
www.asbestos.com

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Jenny Boss Jenny Boss Health Writer Jenny is a health writer and qualified nutritionist with the goal of debunking nutrition myths and making eating well accessible to everyone.

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