What is Mesothelioma and what causes it?
Mesothelioma is a malignant tumour (cancer) of the mesothelium. The mesothelium is the membrane that lines either the chest wall, separating it from the lung (the pleura) or the abdominal wall, separating it from the intestines ( the peritoneum). There can therefore be a mesothelioma of the pleura or peritoneal mesothelioma. Pleural mesothelioma is about 10 times more common than peritoneal.
In the vast majority of cases mesothelioma is caused by inhalation of asbestos fibres. Most common are a result of occupational exposure, but it can also occur from asbestos in the enviroment, or handling or washing clothes of the asbestos workers. There is a long time interval between the expoure and developing mesothelioma, on average about 40 years, but the range can be be 10-60 years. As the use of asbestos in industry and buildings reached a peak in the 1970s before it was banned, we can expect cases to continue to rise for the next 8-10 years.
What are the symptoms?
Pleural mesothelioma
This usually presents with breathlessness,chest pain, or cough, or a combination of these. The breathlessness is usually due to fluid from the tumour filling the pleural cavity and compressing the underlying lung. This is called a pleural effusion. Other less specific symptoms include loss of appetite and weight, fatigue and sweating.
Peritoneal mesothelioma
Common symptoms include abdominal distension due to fluid ( called ascites) and pain. Other local symtoms may include disturbances of bowel function and vomiting. Weight loss,fatigue and swaeting can also occur.
How is it diagnosed?
Pleural mesothelioma
A chest x-ray is usually the start, probably followed by a CT (computerised tomoraphy) or ultrasound scan. The next step willl be to get aa tissue sample. Sometimes the diagnosed is confirmed by drawing off the pleural fluid with a needle, but usually a more formal biopsy is required.
The biopsy can be obtained under local anaesthetic ( CT biopsy) or general anaesthetic (thoracoscopy). Thoracoscopy involves inserting a fibreoptic camera into the pleural space and taking sample under direct vision. The next step is staging, this is to ascertain the extent of the tumour withinthe boddy and is done by a CT scan of the body.
Peritoneal mesothelioma
The process is similar to pleural, except the samples are taken from the peritoneal cavity, by simple aspiration, CT biopsy or a laparoscopy ( under anaesthetic). A staging CT scan will also be done.
