Mesothelioma

Published by Bupa's Health Information Team, July 2010.

This factsheet is for people who have mesothelioma, or who would like information about it.

Mesothelioma is an abnormal and uncontrolled growth of cells in the mesothelium - the thin layer of tissue that lines some of the organs in the body.

How cancer develops

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About mesothelioma

The mesothelium is a thin layer of cells (mesothelial cells) that surround some of the organs in your body.

If you have mesothelioma, your mesothelium thickens due to an abnormal and uncontrolled growth of cells. This causes your mesothelium to restrict the organ it surrounds. Fluid can also collect between the inner and outer layers of your mesothelium, which can put pressure on surrounding organs and tissues.

In the UK, about 2,300 people get mesothelioma each year. Mesothelioma is five times more common in men than women.

Most mesotheliomas are cancerous (malignant). A type of non-cancerous (benign) mesothelioma can develop in the lining of your lungs, or in the lining of your reproductive organs. However, this is rare. This factsheet will concentrate on cancerous mesothelioma only.

Types of mesothelioma

There are two main types of mesothelioma.

• Pleural mesothelioma. This affects the mesothelium surrounding your lungs, which is called the pleura. It's the most common type of mesothelioma. Sometimes, pleural mesothelioma can spread to the mesothelium layer surrounding your heart, which is called the pericardium.
• Peritoneal mesothelioma. This affects the mesothelium surrounding your abdomen (tummy), which is called the peritoneum. This type of mesothelioma doesn't spread to other parts of your body.

Symptoms of mesothelioma

General symptoms of mesothelioma include:

• fever
• sweating - particularly at night
• unexplained weight loss
• feeling tired

If you have pleural mesothelioma you may:

• have chest or back pain
• feel breathless
• cough
• have a hoarse voice
• have difficulty swallowing

If you have peritoneal mesothelioma you may:

• have a swollen abdomen
• have pain in your abdomen
• lose your appetite
• have diarrhoea or constipation

These symptoms aren't always caused by mesothelioma but if you have them, see your GP.

Causes of mesothelioma

Seven to eight out of 10 people with mesothelioma have previously been exposed to asbestos. Asbestos is a mineral that was used in construction, ship-building and household appliances until 1999, when it was banned.

Asbestos is made up of tiny fibres which, when breathed in, pass into your lungs. Here they cause inflammation and fibrous tissues to form. As your body tries to remove these fibres from your lungs, they pass into other areas such as your mesothelium.

Mesothelioma caused by asbestos takes between 15 and 40 years to develop. Because of this, doctors predict that an increasing number of people will be diagnosed with this condition over the coming years.

No-one fully understands what causes mesothelioma in people who haven't been exposed to asbestos. However, certain factors can make mesothelioma more likely, including:

• exposure to radiation
• exposure to zeolite - a Turkish mineral
• previous infection with the Simian monkey virus (SV40) - this may be a co-factor if you have come into contact with one of the other risk factors, such as asbestos

Diagnosis of mesothelioma

Your GP will ask you about your symptoms and examine you. He or she may refer you to a doctor who specialises in conditions affecting the lungs, or a gastroenterologist (a doctor who specialises in conditions of the digestive system). Further tests you may need include the following.

• A chest or abdominal X-ray - to reveal any fluid or swelling.
• Scans - these may include CT, MRI, PET or ultrasound scans.
• Fluid drainage - a sample of the fluid around your lungs or in your abdominal cavity is taken and sent to a laboratory for testing.
• A biopsy - a sample of cells from your pleura or peritoneum is taken and sent to a laboratory for testing.
• A mediastinoscopy - under general anaesthesia, a flexible narrow tube is placed through an incision in your neck to look for mesothelioma in your mediastinum (the centre of your chest).

Treatment of mesothelioma

Treatment depends on how advanced the cancer is. Sometimes, if it's diagnosed early enough, it can be surgically removed. However, as mesothelioma is usually diagnosed late, the cancer may have spread. In this case, treatment aims to ease your symptoms and slow the growth of the cancer.

Medicines

Your doctor may prescribe painkillers or steroid medicines. Steroid medicines, such as prednisolone, can reduce inflammation, improve your appetite and make you feel less tired. Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.

Non-surgical treatments

Chemotherapy
Chemotherapy is a treatment to destroy cancer cells using medicines. The medicines are usually injected into a vein but sometimes you may take them as tablets. Chemotherapy can be given alone, or alongside surgery or radiotherapy to control or shrink the cancer.

Pemetrexed is currently the only medicine licensed in the UK for pleural mesothelioma. It's suitable if your cancer is too advanced for surgery but you're fit enough for treatment. You may have to take it with another medicine called cisplatin, alongside supplements of folic acid and vitamin B12. Other chemotherapy medicines may be available in clinical trials. Ask your doctor for advice.

Radiotherapy
Radiotherapy uses X-rays to destroy cancer cells. It's generally only used to treat pleural mesothelioma, either to stop the cancer returning after you have had surgery or with chemotherapy to control your symptoms.

Fluid drainage
Excess fluid around your lungs or on your abdomen can be regularly drained using a needle. This procedure is carried out under local anaesthesia.

Pleurodesis
This procedure involves chemical powders being put into your pleural space through a tube. The powders inflame the layers of your mesothelium, which makes them stick together so that fluid can't build up between them again.

Surgery

There are several different types of surgery for mesothelioma, depending on which type you have and how advanced it is.

For pleural mesothelioma

• A pleurectomy - an operation to remove as much of the mesothelioma as possible to help control your symptoms.
• Extrapleural pneumonectomy (EPP) is - an operation to remove the whole pleura (mesothelium), your diaphragm, pericardium and one of your lungs.

For peritoneal mesothelioma
The lining of your abdomen (peritoneum) is removed in an operation called a peritonectomy.This may be combined with chemotherapy in a new treatment called cytoreductive surgery, which is suitable for people who have early stage mesothelioma. Chemotherapy is heated and given directly into your abdomen during or after surgery to help kill the mesothelioma.

Physical therapies

You may find physiotherapy, breathing and relaxation techniques helpful.

Help and support

Your doctor will be able to put you in contact with specialist help and support.

If you have mesothelioma because you have been exposed to asbestos, you may be entitled to compensation, either through government benefits and/or suing your employer. Your doctor may be able to put you in contact with a law firm specialising in asbestos claims. Alternatively, you can contact your local citizens' advice bureau for more information.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.