What is mesothelioma?
Mesothelioma is a type of cancer that starts from mesothelial cells. These cells line the outer surface of most of the body's internal organs, forming a protective membrane called the mesothelium.
Some mesotheliomas form a mass (tumour), while others grow along the mesothelium and form a thick covering. In later stages, mesothelioma may spread (metastasise) to other parts of the body.
Your guide to best cancer care
A lot can happen in a hurry when you’re diagnosed with cancer. The guide to best cancer care for mesothelioma can help you make sense of what should happen. It will help you with what questions to ask your health professionals to make sure you receive the best care at every step.
Read the pleural mesothelioma guide
Read the peritoneal mesothelioma guide
Pleural mesothelioma develops in the pleura, the membrane that covers the lungs. The lungs are the main organs for breathing and are part of the respiratory system. About 90% of all mesotheliomas are in the chest.
Although pleural mesothelioma involves the lining of the lungs, it is not lung cancer and is diagnosed and treated differently.
There are two layers in the pleura. The inner layer lines the surface of the lungs and is called the visceral pleura. The outer layer lines the chest wall and the diaphragm, and is called the parietal pleura.
Between the two layers is the pleural cavity, which normally contains a small amount of fluid. This fluid allows the two layers of pleura to slide over each other so the lungs move smoothly against the chest wall when you breathe.
When mesothelioma develops in the pleura, the delicate layers of the pleura thicken and may press on the lung, preventing it from expanding when inhaling. Excess fluid often collects between the two layers. This is called a pleural effusion.
Peritoneal mesothelioma develops in the peritoneum, the membrane that lines the walls and covers the organs of the abdomen and pelvis. These organs include the stomach, bowel, liver, kidneys and, in women, the uterus and ovaries.
Less than 10% of all mesotheliomas are in the abdomen.
The peritoneum has two layers. The inner layer lines the surface of organs such as the bowel, liver and ovaries and is called the visceral peritoneum. The outer layer lines the walls of the abdomen and pelvis, and is called the parietal peritoneum.
Between the two layers is the peritoneal cavity, which normally contains a small amount of fluid. This fluid allows the two layers to slide over each other as you move around.
In people with peritoneal mesothelioma, excess fluid often collects between the two layers. This is known as ascites or peritoneal effusion.
Rare types of mesothelioma
It is rare for mesothelioma to start in more than one area of the body. Rarely, mesothelioma occurs in the pericardium, the lining of the heart. This is called pericardial mesothelioma.
Even more rarely, mesothelioma can occur in the membrane around the testicles, the tunica vaginalis. This is called testicular mesothelioma.
Exposure to asbestos fibres or asbestos dust is the main cause of mesothelioma, but in some cases there is no clear link to asbestos.
Asbestos is a group of naturally occurring minerals that are resistant to high temperatures and humidity. It was used in many building products in Australia from the 1940s until 1987. Since 2004, Australia has banned asbestos being sold, reused and/or imported.
Despite the ban, asbestos has been found in some products recently imported from overseas. It is still found in many older buildings, so special care needs to be taken when renovating.
It can take many years for mesothelioma to develop after a person is exposed to asbestos. This is called the latency period or interval – it is usually between 20 and 60 years (most commonly around 40 years) after exposure.
How common is mesothelioma?
Australia has one of the highest rates of mesothelioma in the world, with 757 Australians diagnosed in 2016. Men are four times more likely than women to be diagnosed with mesothelioma, probably because many cases have been caused by exposure to asbestos at work.
Pleural mesothelioma makes up about 93% of all mesothelioma cases. Peritoneal mesothelioma is less common and makes up nearly 7% of cases. Mesothelioma is more common in people over the age of 65, but can occur in younger people.
The first signs of mesothelioma are often vague and similar to other conditions. It may take some time to be diagnosed, as the symptoms may come and go, and more common conditions are likely to be investigated first.
Pleural mesothelioma may cause:
- shortness of breath, which usually feels worse with activity or when you are lying down
- pain in the chest around the ribs or in the shoulder, which may be sharp and stabbing, made worse by breathing in deeply, or dull and persistent
- extra sensitive skin or change in skin sensation
- loss of appetite with weight loss
- loss of muscle bulk
- loss of energy
- a persistent cough or a change in coughing pattern
- night sweats.
Peritoneal mesothelioma may cause:
- abdominal pain
- a swollen abdomen
- poor appetite, nausea and vomiting
- night sweats or fever
- bowel or urinary problems.
Let your GP know if you may have been exposed to asbestos in the past. Finding mesothelioma early will mean you have more treatment options.
If you have mesothelioma, you will be cared for by a range of health professionals who specialise in different aspects of your care. This is known as a multidisciplinary team (MDT) and may include a gastroenterologist, respiratory physician, thoracic surgeon and dietician, among others.
Download our Understanding Mesothelioma booklet learn more.Download now
Expert content reviewers:
A/Prof Brian McCaughan, Cardiothoracic Surgeon, Chris O’Brien Lifehouse, NSW; Theodora Ahilas, Principal Lawyer, Maurice Blackburn Lawyers, NSW; Prof David Ball, Director, Lung Service, Peter MacCallum Cancer Centre, VIC; Shirley Bare, Consumer; Cassandra Dickens, Clinical Nurse Consultant, Cancer Care Coordinator – Thoracic Malignancies, Sunshine Coast University Hospital, QLD; Penny Jacomos, Social Worker, Asbestos Diseases Society of South Australia, SA; A/Prof Thomas John, Medical Oncologist, Senior Clinical Research Fellow, Austin Health, and Olivia Newton-John Cancer Research Institute, VIC; Victoria Keena, Executive Officer, Asbestos Diseases Research Institute, NSW; Penny Lefeuvre, Consumer; Jocelyn McLean, Mesothelioma Support Coordinator, Asbestos Diseases Research Institute, NSW; Prof David Morris, Peritonectomy Surgeon, St George Hospital and University of New South Wales, NSW; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council Western Australia; Prof Anna Nowak, Medical Oncologist, Sir Charles Gairdner Hospital, and Professor of Medicine, School of Medicine and Pharmacology, The University of Western Australia, WA; Prof Jennifer Philip, Palliative Care Specialist, St Vincent’s Hospital, Peter MacCallum Cancer Centre and Royal Melbourne Hospital, VIC; Nicole Taylor, Acting Lung Cancer and Mesothelioma Cancer Specialist Nurse, The Canberra Hospital, ACT.
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The information on this webpage was adapted from Understanding Mesothelioma - A guide for people with cancer, their families and friends (2019 edition). This webpage was last updated in August 2021.