What is mesothelioma?

Mesothelioma is an uncommon type of cancer that occurs in the tissues covering your lungs or your tummy (abdomen). Past exposure to asbestos is a risk factor for mesothelioma. Initial symptoms are variable but can include shortness of breath, chest pain or abdominal swelling. Although a cure is often not possible, there are different treatments to help any symptoms you may have.

What is cancer?

Cancer is a disease of the cells in the body. The body is made up from millions of tiny cells. There are many different types of cell in the body and there are many different types of cancer which arise from different types of cell. What all types of cancer have in common is that the cancer cells are abnormal and multiply 'out of control'.

A malignant tumour is a 'lump' or 'growth' of tissue made up from cancer cells which continue to multiply. Malignant tumours invade into nearby tissues and organs, which can cause damage. Malignant tumours may also spread to other parts of the body. This happens if some cells break off from the first (primary) tumour and are carried in the bloodstream or lymph channels to other parts of the body. These small groups of cells may then multiply to form 'secondary' tumours (metastases) in one or more parts of the body. These secondary tumours may then grow, invade and damage nearby tissues and spread again.

Some cancers are more serious than others, some are more easily treated than others (particularly if diagnosed at an early stage) and some have a better outlook than others.

So, cancer is not just one condition. In each case it is important to know exactly what type of cancer has developed, how large it has become and whether it has spread. This will enable you to obtain reliable information on treatment options and outlook.

See separate leaflet called What is Cancer? for further details about cancer in general.

What is mesothelioma?

Mesothelioma is a type of cancer that occurs in the tissues which cover your lungs or tummy (abdomen). The lining around the lungs is the pleura and in the abdomen it is called the peritoneum.

About 2,700 people in the UK are diagnosed with mesothelioma each year. Men are five times more likely than women to develop a mesothelioma. It most commonly occurs in people aged over 75 years.

Mesothelioma most commonly occurs in your pleura - the linings of your lungs. There are two layers of pleura - one lining your lungs and the other lining your chest wall. These two layers have some fluid in between them so they can slide over each other easily when you breathe in and out.

In a similar way, the lining of your abdomen also has two layers - one lining your bowel and abdominal organs and the other lining your abdominal wall. A mesothelioma occurring in your peritoneum is far less common than a mesothelioma occurring in the pleura.

Very rarely, mesothelioma can occur around your heart or your testicles (testes). This leaflet will not discuss these rare types of mesothelioma.

What causes mesothelioma?

A cancerous tumour starts from one abnormal cell. It is thought that something damages or alters certain genes in the cell. This makes the cell abnormal and multiply 'out of control'. Certain risk factors increase the chance of certain cancers forming. See separate leaflet called What Causes Cancer? for more details.

The most important risk factor for developing mesothelioma is being exposed to asbestos in the past. Around nine out of ten people with a mesothelioma have been exposed to asbestos in the past. A mesothelioma may even occur up to 50 years after you have been exposed to asbestos.

Compensation is possible if your mesothelioma is due to asbestos exposure. This can be done either through benefits paid by the government or, if you believe your mesothelioma is due to asbestos exposure within a work environment, by suing the employer in question for the period (or periods) during which you were exposed to asbestos.

What is asbestos?

Asbestos is a material that was used in buildings in the past. It is an insulating material that is both heat-resistant and fire-resistant. There are different types of asbestos: white, brown and blue. Although they are all harmful, blue and brown asbestos are the most strongly linked with mesotheliomas and they have not been imported into the UK since 1985. However, they are still present in some buildings and equipment produced before the ban. White asbestos has been banned in the UK since 1999.

Asbestos materials which are left undisturbed are probably safe. It is asbestos dust or fibres which cause the harm when they are breathed in (inhaled) or swallowed (ingested).

Note: the majority of people who have been exposed to asbestos in the past are not likely to develop mesothelioma. However, it is not possible to identify which people exposed to asbestos are likely to develop mesothelioma in the future. As a general rule, the greater and more prolonged the exposure, the greater the risk.

What are the symptoms of mesothelioma?

The symptoms depend on the site of the mesothelioma. It often takes many years after being exposed to asbestos for mesothelioma to occur.

In the early stages, there may be no symptoms at all. Both types of mesothelioma can cause nonspecific symptoms such as increasing tiredness, weight loss, increased sweating and a reduction in your appetite.

When mesothelioma develops in the pleura, this causes the pleura to thicken and it may press inwards on the lung.

Symptoms may then include:

• Shortness of breath. This may be due to the pleura becoming thickened and pressing in towards your lung. In addition, an increase in the amount of fluid may also collect between the two layers of the pleura (a pleural effusion).
• Chest pain. This can be quite severe and can be due to the mesothelioma pressing on the nerves and even the bones near your lung.
• Cough.
• Hoarse voice.

Tummy (abdominal) swelling may occur if you have mesothelioma in your peritoneum. The lining of the abdomen becomes thickened and fluid can collect in the abdomen (ascites).

If the cancer spreads to other parts of the body then various other symptoms can develop.

to be continue........