Mesothelioma is a form of cancer which affects the membrane which surrounds the lungs called the pleura or, less commonly, the membrane enclosing the contents of the abdomen (the peritoneum).

Mesothelioma is very uncommon but has become more frequent over the last few decades. It is more often seen in men than women, and occurs in older age, usually around 60. Exposure to asbestos is now recognised as the major cause of mesotheliomas. About four out five people with mesothelioma have a history of asbestos exposure. Usually contact with asbestos will have occurred many years before the cancer develops, 30 to 40 years being typical. There are various types of asbestos and some of these are more likely to cause mesotheliomas than others. For example crocidolite and amosite are types of asbestos strongly linked to mesothelioma whereas chrysotile, another sort of asbestos, seems to carry a very low risk.

As the link between asbestos and mesothelioma was only found in the 1960s and time between exposure and the cancer appearing can be so long, it means that although contact and use of asbestos has been greatly reduced in recent years, new cases of mesothelioma are still appearing in increasing numbers.

For one in ten people there does not seem to be any evidence of contact with asbestos and the cause of the mesothelioma remains a mystery for most of them although occasionally previous exposure to radiation may be a factor. Smoking cigarettes does not increase the risk of developing mesothelioma.

When mesothelioma affects the pleura, the outer lining of the lungs, the commonest symptom is persistent chest pain. This may be accompanied by other symptoms such as breathlessness, a persistent cough or hoarseness of voice.

When mesothelioma affects the peritoneum, the lining membrane of the abdomen, then abdominal pain and swelling are the main problems.

Unfortunately mesothelioma is very resistant to treatment. If it is confined to a small area then an operation may be possible to remove it. If it is more widespread then a partial removal may be possible, and radiotherapy or chemotherapy may sometimes help to control the cancer but a cure is not possible.