Mesothelioma
General Information / Anatomy / Function / Statistics
Mesothelioma are tumours originating from the lining of the body cavities; this includes the chest and abdomen. Although the most common type of mesothelioma begins within the chest, this cancer should not be confused with lung cancer. Mesothelioma arises from the serosal lining outside of the lungs within the chest or outside the bowel within the abdomen.
Malignant mesothelioma is usually not curable.
Symptoms / Signs
Symptoms and signs from mesothelioma depend upon location of the mesothelioma, its size and whether it is benign or malignant. Benign forms of the disease are generally asymptomatic. The symptomatology of malignant mesotheliomas is due to tumour growth resulting in invasion of surrounding structures and/or the production of fluid (pleural effusion, ascites, or pericardial effusion). Chest pain may be caused by invasion of the chest wall. Pleural effusion causes collapse of adjacent lung and shortness of breath.
Symptoms of distant spread are possible, but uncommon since the tumour is usually a local problem and blood borne spread is uncommon. Patients with more advanced disease may be ill generally with fever, night sweats and weight loss. Involvement of the membrane around the heart (pericardium) may cause heart rhythm disturbances.
Carcinogens / Risks
There is a definite association between asbestos and mesothelioma. The risk associated with asbestos exposure has been shown by many investigators and inhalation of asbestos poses the most serious hazard. Crocidolite (Cape blue asbestos), the main cancer causing form of asbestos, is associated with over 90% of pleural and peritoneal mesotheliomas. Individuals at highest risk are those employed in the asbestos industry; dockyard workers, especially if they dismantle asbestos-insulated steam piping; those who handle and manufacture asbestos compounds; insulators and steam fitters; and those in demolition and construction industries. Spouses and children of asbestos workers are also at risk. The latent interval between exposure to asbestos and development of tumour is long (15-25 years).
Prevention
The only method of prevention is avoidance of asbestos exposure.
Diagnosis / Staging / Grading / Types
The chest X-ray is a very helpful test, usually showing thickening of the pleura or pleural effusion in patients with pleural mesothelioma. Sometimes a CT scan of the chest may be required for further information. A pleural biopsy is essential for pathological confirmation of the disease.
Types
Mesothelioma may be of epithelial or sarcomatous. Sarcomatous types are more malignant and tend to be resistant to treatment.
Treatment
Malignant mesotheliomas are serious illnesses and cure of the disease is rare.
Survival with this type of cancer obviously varies with the extent of the disease, but overall it is in the region of one year.
Surgery
Because of the large area of pleural surfaces, complete surgical removal is rarely technically feasible. The advisability of resection is always considered at diagnosis, but only a small minority of cases are eligible for an attempted resection. Spread of disease to the chest wall, heart, or esophagus often rules out the possibility of an operation.
Radiation
Radiation may be given for control of symptoms in a localized area. Radiation therapy does not have the power to cure this disease. Radiation cannot be given to the entire tumour because this would involve the treatment of large volumes of normal tissue and the dose of radiation required for tumour control is too high for this to be tolerated. Radiation can, however, be of value in controlling pain in a localized area.
Chemotherapy
Benefits from chemotherapy treatments for mesothelioma are uncertain as the tumour is often resistant. 20% of patients may have a temporary shrinkage of the disease with currently available drugs.
General Support and Symptom Control
If pain is associated with mesothelioma, good drug prescriptions are available that can control this. Pleural effusions (fluid build up) can be treated by a small surgical procedure that removes the fluid, permitting re-expansion of the lung and improvement in shortness of breath. Some patients with mesothelioma may have very slow growing tumours and if symptoms are not present, it is often advisable to follow the patient with regular chest X-rays without specific therapy.
ehealthy.ca
