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: Mesothelioma may not appear until 20 to 50 years after exposure to asbestos. Diagnosing it is often difficult, because the symptoms are similar to those of a number of other conditions. The symptoms include shortness of breath due to pleural effusion (fluid between the lungs and the chest wall) or chest wall pain, and more general 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 disease has spread beyond the mesothelium to other areas of the body, signs may include pain, having trouble 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 several types of treatment options available: Radiation, Surgery, and chemotherapy including recently approved medications. Despite treatment with chemotherapy, radiation therapy or sometimes surgery, the disease carries a poor prognosis. For patients with localized disease, and who can tolerate a radical surgery, radiation is often given post-operatively as a consolidative treatment.

Although the cancer is usually resistant to curative treatment with radiotherapy alone, palliative treatment regimens are sometimes used to relieve symptoms caused by tumor growth, such as obstruction of a major blood vessel. In February 2004, the U.S. Food and Drug Administration approved pemetrexed (brand name Alimta) for treating malignant 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 disease is found only on the membrane surface where it began. Screening tests might diagnose it earlier than conventional methods thus raising 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 suggested that in humans, transport of fibres to the pleura is critical to the pathogenesis of the disease.

Experimental evidence indicates that asbestos acts as a complete carcinogen with the development of mesothelioma happening in sequential stages of initiation and promotion.

Although reported incidence rates have grown in the past 20 yrs, the disease is still a very rare cancer. Incidence of malignant mesothelioma currently ranges from about 7 to 40 cases per 1,000,000 in industrialized Western nations, depending on the amount of asbestos exposure of the populations during the past few 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 increase 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 have resulted.