INTRODUCTION: Mesothelioma is a form of cancer that is almost always caused by previous exposure to asbestos. Most people who develop it have worked on jobs where they inhaled asbestos particles, or they have been exposed to asbestos dust and fibre in other ways, such as by washing the clothes of a family member who worked with asbestos.
It is a serious disease with an average survival time of only 1 to 2 years after diagnosis. Unlike lung cancer, there is no association between mesothelioma and smoking. The disease occurs more often in men than in women and risk increases with age, but this disease can appear in either men or women at any age. It is also known to occur in those who are genetically pre-disposed to it.
SYMPTOMS: It may not appear until 20 to 50 yrs after exposure to asbestos. Diagnosing it is usually difficult, because the symptoms are like those of a number of other conditions. These symptoms include shortness of breath due to pleural effusion (fluid between the lungs and the chest wall) or pain of the chest wall, and more generalized symptoms such as weight loss.
Signs of mesothelioma may also include abdominal pain, ascites, or an unusual buildup of fluid in the abdomenal mass in the abdomen, bowel function problems. Other signs of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and high body temperature.
If the cancer has metastatized beyond the mesothelium to other parts of the body,possible signs may include pain, trouble with swallowing, or swelling of the neck or face.
In severe cases of the disease, the following signs may be present: blood clots in the veins, which may lead to thrombophlebitis, disseminated intravascular coagulation, a situation causing severe bleeding in many body organs, jaundice, or yellowing of the eyes and skin, low blood sugar level, pleural effusion, pulmonary emboli, or blood clots in the arteries of the lungs, severe ascites. These symptoms may be brought about by mesothelioma or by other, less serious diseases.
TREATMENT: There are number of types of treatment options available: Radiation, Surgery, and chemotherapy including newly approved medications. Despite treatment with chemotherapy, radiation therapy and sometimes surgery, the disease has a poor prognosis. For those with localized disease, and who can tolerate a radical surgery, radiation is usually given post-operatively as a consolidative treatment.
Although the disease is normally resistant to curative treatment with radiotherapy alone, palliative treatment regimens are sometimes used to ease symptoms arising from tumor growth, such as blockage of a major blood vessel. In February 2004, the United States FDA approved pemetrexed (brand name Alimta) for treatment of cancerous pleural mesothelioma.
CONCLUSION: Mesothelioma is a type of cancer that is nearly always caused by previous exposure to asbestos. Cancer that affects the pleura can cause these signs and symptoms: A painful chest wall, pleural effusion, or fluid surrounding the lungs, shortness of breath, fatigue or anemia, wheezing, hoarseness or cough, blood in the sputum (fluid) coughed up (hemoptysis).
It is described as localized if the condition is found only on the membrane surface where it started. Screening tests might diagnose mesothelioma earlier than conventional methods thus increasing the survival prospects for patients.
The processes leading to the development of peritoneal mesothelioma remain unresolved, although it has been proposed that asbestos fibres from the lung are transported to the abdomen and associated organs via the lymphatic system.
It has been argued that in humans, transport of fibres to the pleura is critical to the pathogenesis of the condition.
Experimental evidence suggests that asbestos acts as a total and complete carcinogen with the development of mesothelioma occurring in sequential stages of initiation and promotion.
Although reported incidence rates have risen in the past 2 decades, the disease is still a relatively rare occurence. Incidence of malignant mesothelioma presently ranges from about 7 to 40 per 1 million in industrialized Western nations, depending on the amount of asbestos exposure of the populations during the past several decades.
Between 1973 and 1984, there has been a threefold increase in the diagnosis of pleural mesothelioma in Caucasian males. From 1980 to the late 1990s, the death rate from mesothelioma in the USA increased from 2,000 per year to 3,000, with men four times more likely to acquire it than women. These rates may not be accurate, since it is possible that many cases are mis-diagnosed as adenocarcinoma of the lung, which is difficult to differentiate from mesothelioma.
Working with asbestos is the most important risk factor for mesothelioma. However, the disease has been reported in some people without any known asbestos exposure. Besides mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous, chronic lung ailment), and others, such as cancer of the larynx and kidney.
Smoking modern cigarettes does not appear to raise the risk of developing the disease. The Kent brand of cigarettes used asbestos in its filters for the first few years of production in the 1950s and some cases of mesothelioma are the result.