Pleural mesothelioma develops when the cancer affects the pleura {the membranous lining of the lungs}.This form of cancer is commonest in the UK, followed by South Africa, then Australia, then USA, then Eastern Europe.

The pleura has two layers which gives support and protection to the lungs and chest cavity:

-The outer layer, or parietal layer, lines the entire chest cavity and the diaphragm.

-The inner layer or the visceral layer which applies directly over the lungs.

Pleural mesothelioma can start from any of these two layers then spread to the other layer. Exposure to asbestos has been strongly linked to the development of this type of cancer. The toxic fibers get trapped in the spaces between the mesothelial cells of the pleura.

Symptoms

The asbestos fibers trapped in the body cause cancerous cells to multiply and divide haphazardly without control. These results in the thickening of the pleural membrane and mesothelial cells, leading to fluid build up in the pleura {pleural effusion}. This accumulated fluid will gradually start pressing on the lungs and the respiratory system leading abnormal and difficult breathing.

These developments eventually form the basis of most of the symptoms of pleural mesothelioma. These symptoms include:

A} Persistent dry or raspy cough

B} Haemoptysis, the coughing up of blood in the sputum

C} Difficulty in swallowing {dysphagia}

D} Difficulty in breathing, laboured breathing known as dyspnoea

E} Pleurisy, pain in the chest during breathing

F} Development of lumps under the skin of the chest wall

G} Night sweats or fever

H} Unexplained weight loss

I} Fatigue

Diagnosis

Just like in other forms of mesothelioma, the symptoms of pleural mesothelioma show up many years after the initial exposure to asbestos and these symptoms are not specific to pleural mesothelioma, they also occur in some other less serious lung diseases like pneumonia and influenza.

All these factors make the diagnosis of pleura mesothelioma very difficult.

Once there is a strong clinical suspicion of pleural mesothelioma, diagnosis is then confirmed by imaging tests such as x-rays, CT scan, to confirm the location of the cancer. The patient is also subjected to fluid and tissue analysis known as biopsy to confirm the type of cancer involved.

Treatment

Newly developed drugs and detection techniques have improved the outlook for patients with pleural mesothelioma.

In general there are three main modes of treatment: a} Surgery b} Chemotherapy c} Radiotherapy. Most patients receive a combination of two or more of the different modes of treatment.

The earlier the cancer is detected, the better the prognosis and the wider the range of treatment options. When the tumor is detected early, curative surgery is done to remove the cancer, this is followed by chemotherapy or and radiotherapy to kill off any remnant cancerous cells. Curative surgeries is only carried out in patients that have good general state of health and whose cancers have not spread beyond localized sections of the lungs.

The level of progression of the tumor is classified in terms of the stage of the cancer. The stages range from stage 1 to stage 4 depending on the level of spread of the tumor.

Stage 1 and Stage 2 pleural mesothelioma have better prognosis and better treatment options.

The latter stages of the cancer, namely stage 3 and stage 4 are mostly limited to palliative modes of treatment to improve the quality of life and not their prognosis. These palliative treatments include the draining of excessive fluids in the pleural spaces and surgical removal of tumors to relieve pressure on the lungs.

According to current studies, approximately 10% of all pleural mesothelioma patients will survive for three to five years after diagnosis and 5% will survive for 5 years and above.