Mesothelioma (also known as ‘diffuse' or ‘malignant' Mesothelioma) is a type of cancer, which typically affects the thin membranes that line the chest (pleural mesothelioma). Less commonly it can affect the linings of the abdomen (peritoneal mesothelioma). It may also affect the lining of the heart {pericardial mesothelioma} and very rarely the lining of the testes {testicular mesothelioma}.



Pleural Mesothelioma

The pleural lining has two layers - an inner (visceral) layer which lines the lung and an outer (parietal) layer which lines the chest wall. The pleura produces pleural fluid to lubricate the space between the two layers allowing the layers to slide easily over each without friction other as we inhale and exhale during breathing.

Pleural Mesothelioma causes the pleura to thicken. This will lead to compression of the lung or attachment of the tumor to the chest wall. Fluid, sometimes several litres, can collect between the two layers and cause breathlessness. This is known as a Pleural effusion.

Peritoneal Mesothelioma

The peritoneum also has two layers, the inner (visceral) layer which is next to the abdominal organs and the outer (parietal) layer which lines the abdominal wall. This cancer will make the peritoneum to thicken and fluid to collect in the abdomen, this collection of fluid is called ascites and it causes abdominal swelling. Peritoneal Mesothelioma is not as common as Pleural Mesothelioma.

What causes Mesothelioma?

Exposure to asbestos is the major cause of this type of cancer. There may however be some other unknown less common causes. It has previously been a rare disease but is now occurring more frequently because of the heavy use of asbestos in the post-war years. For most people diagnosed with Mesothelioma the exposure happened 20-40 years before the onset of symptoms (It may in some instances be a longer or a shorter interval than this.). Sometimes the asbestos exposure may have been very brief and not always easy to identify. However most commonly, the cancer usually shows up in people that have had repeated exposure to asbestos, usually in a working environment. There are several types of asbestos all of which have been known to cause Mesothelioma.

How is Mesothelioma diagnosed?

Early diagnosis is difficult as the symptoms do not appear until the disease is well advanced, and in most cases the first obvious sign is sudden difficulty in breathing caused by an accumulation of fluid in the pleural space - a pleural effusion. There may also be some other symptoms like as chest pain, weight loss, hemoptysis {coughing blood in sputum},and anaemia. Scans and X-rays can provide strong evidence to support the diagnosis especially coupled with a history of asbestos exposure. However, these symptoms are also common to other less serious diseases so other diseases to be certain of a correct diagnosis more investigations often need to be carried out.

These tests include Scans, Fluid taken for laboratory examination, possibly needle biopsy or keyhole surgery to take a biopsy (a small sample of tissue) is likely to be carried out to help with the confirmation of the diagnosis. These tests and results may take several weeks to complete.

What are the available treatment options?

Mesothelioma does not respond very well to usually recommended cancer therapy such as chemotherapy and radiotherapy. There are a number of trials being run in an attempt to improve treatment but nothing has been found to cure this disease. The type of treatment offered depends on several factors. These should include patient choice, the general condition of the patient, and the stage of the how cancer {the level of advancement of the cancer}.

The initial most helpful treatment is that which deals with symptoms.

Removing fluid from around the lung can help to relieve breathlessness. Firstly the fluid may be drained either by drawing off fluid or inserting a small drainage tube. However the fluid often re accumulates and the chest physician or surgeon may perform a procedure called a ‘Pleurodesis'. This is an attempt to stick the lung surface to the chest wall by inserting sterile talc into the pleural space. This may be done by a surgeon using ‘key hole surgery' otherwise called VATS - Video Assisted Thoracoscopic Surgery.

Surgery

There are minor forms of surgery which the surgeon may carry out during the VATS procedure to remove some of the bulk of the tumour. Surgery may also improve some of the symptoms of the disease.

A very major operation which is called an Extra-pleural Pneumonectomy(EPP) is only suitable for a very select group of patients with early stage disease and who are physically and mentally able to tolerate such extensive surgery. The operation involves the removal of the whole affected lung along with its lining, the lining of the heart and part of the

diaphragm. This operation can only be carried out by a limited number of thoracic surgeons in the country.

Chemotherapy

This is drug treatment used to try to destroy or control cancer cells. Unlike some other cancers there is no evidence that chemotherapy ever cures Mesothelioma. Some trials and studies have however indicated that it may help to improve symptoms temporarily and may extend life expectancy slightly.

Not all patients with Mesothelioma will benefit from chemotherapy and there is no way of knowing which patients will benefit and which will not. It is important for you to discuss this with the doctors and nurses involved in providing it.

Radiotherapy

This is the use of high energy radiation to kill diseased cells in the body.

In Mesothelioma it can be used in two ways:

1) A short course of treatment to the chest wall where a biopsy has

been done. This is a preventative measure and is intended to stop

Mesothelioma growing in the skin layer.

2) Some patients with pain may get some benefit from radiotherapy to help to kill any remaining cancer cells after major surgery.