Mesothelioma is a tumour that most often develops in the pleura of the chest wall, although it can also extend to the pleura that covers the lungs. Between the pleura is the pleural cavity. Mesothelioma can also develop in the membrane that covers the heart (the pericardium) or the membrane that forms the lining of the abdominal cavity (peritoneum). These membranes are composed of connective tissue and cells. These cells can become malignant and form tumourous growths. Mesotheliomas are rare tumours that can be malignant or benign. Malignant mesotheliomas affect the pleura of the chest wall in 75% of cases.
Tumours arise after cells are damaged and they then begin to grow and replicate uncontrollablely. Tumours can be cancerous or non-cancerous (malignant or benign). Cancerous tumours grow quickly and aggressively, and spread into surrounding tissues where they form metastases (areas of secondary growth further away from the original tumour site). Non-cancerous tumours grow slowly and do not spread into surrounding tissues and do not metastasize. The disadvantage of non-cancerous tumours is that they can press on surrounding tissues and potentially negatively affect their function.
Risk factors for mesothelioma
The most serious risk factor for the emergence of mesothelioma is exposure to asbestos, which is a carcinogenic material. Asbestos induces malignant cell growth, where cells begin to replicate and grow uncontrollablely. Asbestos enters the body when it is breathed into the lungs and causes diseases of the respiratory system. Apart from causing mesothelioma, asbestos also causes an illness called asbestosis. Contact with asbestos is documented in more than half of individuals with mesothelioma. Affected individuals are most often those that have direct contact with asbestos in their professions, such as miners and factory workers. Family members of these workers are also at risk because asbestos fibers cling to the clothes and therefore the workers bring asbestos into their homes. Indirect contact also increases risk and this is most common for people that live in buildings built with materials containing asbestos. This is why asbestos is no longer used in building materials, although it can still be a part of many old buildings. The period of time between contact and appearance of mesothelioma is 20-40 years. The tumour occurs most commonly around the age of 60. Apart from asbestos, genetic factors may also play a part in the formation of mesothelioma.
Symptoms of mesothelioma
Symptoms of mesothelioma are most often chest pain, shortness of breath and hacking cough. As these symptoms can be caused by many other illnesses, it is important to inform your physician of contact with asbestos. Mesothelioma can also damage other organs, such as the spine, esophagus, and the superior vena cava. Mesothelioma commonly causes fluid to accumulate in the pleural cavity, which can compress the lungs. Other symptoms include fever, large weight loss in a short amount of time and lack of appetite. These are general symptoms of cancer. The weight loss can occur even without loss of appetite. Mesothelioma has a very poor prognosis.
Diagnosis and treatment of mesothelioma
The main diagnositc tool for mesothelioma is the chest X-ray, followed by the CT scan. CT scans are a modern diagnostic tool that use X-rays to form a very detailed picture of an organ’s tissues. The disadvantage of the CT is that the individual receives a very large dose of radiation. Another method is the MRI (magnetic resonance) which uses a magnetic field to create the picture and therefore is not as harmful to the pacient. Although the disadvantage of the MRI is its high cost. In order to confirm the diagnosis of mesothelioma a biopsy must be taken. Treatment is lead by an oncologist. The basic treatment plan includes surgery, radiation and chemotherapy, that are selected based on the stage of the tumour and the overall health of the pacient. The first choice is surgery where the entire tumour may be removed, followed by radiation and chemotherapy. If the pacient is unable to undergo surgery then treatment begins with chemotherapy.
Prevention of mesothelioma
The most important step to preventing the occurence of mesothelioma is to remove asbestos from living environment. Individuals that work in an at-risk environment must complete regular physicals and in case of the appearance of the discussed symptoms of mesothelioma, they should immediately contact their physician. If the diagnosis of mesothelioma is confirmed then the pacient must avoid all contact with the harmful factors.