Mesothelioma-Medical Information

Malignant mesothelioma is an uncommon tumor. The incidence of malignant mesothelioma in the general population is one to two cases per million. The association between asbestos with mesothelioma is well established. and it is clear that the vast majority of mesothelioma cases arise in people exposed to asbestos fibers.

All asbestos fiber types produce mesothelioma, including amosite which was typically used in pipe coverings and insulation, as well as chrysotile which was used in building products and brakes. Because all commercial forms of asbestos both initiate and promote the growth of tumors, asbestos is considered a complete carcinogen in the induction of mesothelioma.

Usually, shortness of breath or chest wall pain are the first symptoms noticed by the patient. . Many times, chest x-rays will reflect a pleural effusion-accumulation of fluid around the lungs.. Fever, weight loss and declining physical performance are other complaints frequently encountered. The median duration of survival, according to the literature, is 4 to 18 months. However, many new treatment protocols are having success in prolonging life expectancy. For a list of links to sites which discuss the variety of possible treatments, click here.

On chest x-rays, malignant mesothelioma typically appears as diffuse nodular thickening of the pleura. The involved hemithorax generally shows volume loss despite a large tumor volume. As the tumor advances, there is encasement of the underlying lung and fixation or shift of the mediastinum. CT scans are a necessary for staging and more accurate than chest x-rays for defining the extent of the tumor, invasion of other sites and the status of the underlying lung.

Pathology materials are needed for a definitive diagnosis. Sometimes the diagnosis can be made on the basis of cytology-examination of the pleural fluid. A biopsy is often the preferred method of diagnosis. Needle biopsy is frequently utilized, although and open thoracotomy biopsy is optimal for establishing a firm diagnosis of malignant mesothelioma.

The role of surgery other than for biopsy in mesothelioma remains a topic of ongoing research and experimentation. One of the standard approaches in the treatment of recurrent pleural effusions is to attempt to obliterate the pleural space by producing an irritation or inflammation of the pleural surfaces, thereby causing them to adhere, thus eradicating the target space for future effusions. This is called pleurodesis. Techniques to accomplish this have included the instillation of various agents, such as talc, radioisotopes, antibiotics, antiparasitics, chemotherapeutic agents, biologic substances and steroids. The approaches and agents have met with varying levels of clinical response and further research continues with regard to these procedures. Another, more invasive, option for the control of recurrent pleural effusions is the use of thoracotomy and pleural stripping or pleurectomy, thereby achieving a mechanical form of pleurodesis. Although highly successful in achieving control of pleural effusions it is of very limited potential application because of the high morbidity and mortality associated with the procedure, even in experienced hands in those individuals with advanced disease. The current literature recommends that this procedure be reserved for the relatively healthy patient. Because of the progressive nature of mesothelioma and the extent of surgery needed to eradicate the disease, any patient considered for radical surgery must be able to withstand possible major surgery and prolonged anesthesia. Many cancer experts advocate supportive care alone.

For more information on mesothelioma, see the National Cancer Institute's PDQ on mesothelioma at: http://www.cancer.gov/CancerInformation/CancerType/malignantmesothelioma