Mesothelioma is cancer of the mesothelial cells. These cells make up the membrane (lining) that covers the outer surface of most of our body’s organs.

There are two main types of mesothelioma:

• pleural mesothelioma – the most common type, which develops in the tissue covering the lungs
• peritoneal mesothelioma – which develops in the lining of the tummy (abdomen)

Symptoms of mesothelioma

Symptoms of pleural mesothelioma can include:

• pain in the chest or lower back
• shortness of breath
• a high temperature (fever) of 38ºC (100.4ºF) and sweating, particularly at night
• a persistent cough
• unexplained weight loss

Symptoms of peritoneal mesothelioma can include:

• pain or swelling in the tummy (abdomen)
• feeling sick (nausea) or being sick (vomiting)
• loss of appetite
• unexplained weight loss
• diarrhoea or constipation

In very rare cases, mesothelioma can affect the lining around the testes (testicular mesothelioma). The main symptom of this is a fluid-filled sac on a testicle.

Who is at risk?

Over 2,500 people in the UK are diagnosed with mesothelioma each year, and men are five times more likely to be diagnosed than women.

Mesothelioma is almost always caused by exposure to asbestos. Asbestos is a soft, greyish-white material that used to be widely used in building construction as a form of insulation and to protect against fire.

Mesothelioma usually develops many years (usually 20 to 60) after the initial exposure.

Read more information about the effects of prolonged exposure to asbestos.

When to see your GP

See your GP if you notice any unusual or persistent symptoms, particularly if you have been exposed to asbestos in the past. It’s unlikely to be mesothelioma, but it’s important to get checked out by a doctor.

If you are referred to hospital for further tests, they may include:

• imaging studies – such as an X-ray, CT scan, MRI scan or ultrasound scan
• a thoracoscopy – a surgical procedure, usually performed under sedation or a general anaesthetic (where you are made very sleepy or put completely to sleep), which allows the doctor to examine your chest and take a biopsy (a sample of tissue) without having to make a large incision in the skin
• fluid drainage (pleural aspiration) – if there is a build up of fluid around the lungs or abdomen, a sample may be taken by inserting a needle through an area of skin (usually guided by ultrasound) that has been numbed with local anaesthetic

Mesothelioma can be difficult to diagnose, as the cells can be hard to recognise. They may also look like normal cells or another type of cancer, such as lung cancer or ovarian cancer.

Treating mesothelioma

The best treatment for mesothelioma depends on several factors, including the stage of your cancer and your general health.

Chemotherapy is the main treatment for mesothelioma. This involves using medicine to help control symptoms and shrink a tumour.

In some cases, radiotherapy (using high-energy radiation) may be used to help prevent complications of mesothelioma from developing.

There are several surgical treatments being investigated as potential treatments for mesothelioma. However, there is no strong evidence that they are effective treatments.

As mesothelioma is often diagnosed at an advanced stage, treatment is usually focused on controlling the symptoms for as long as possible. This is known as palliative or supportive care.

Outlook

The outlook for mesothelioma is poor, because it is usually diagnosed at an advanced stage. Unfortunately, most people diagnosed with mesothelioma will die within three years of being diagnosed, and the average person survives for around 12 months. Every year in the UK, there are around 2,300 deaths from the condition.

The number of deaths from mesothelioma is expected to rise, due to the long gap between exposure to asbestos and the onset of the cancer. Experts believe that by 2050, 90,000 people in the UK will have died as a result of mesothelioma.

Want to know more?

• Cancer Research UK: mesothelioma 
• Macmillan: mesothelioma
• Asbestosis