Mesothelioma: Causes, Symptoms, Diagnosis, and Treatment

Mesothelioma is a rare type of cancer of the mesothelium, the protective covering on and around most of the organs in the human body. The major cause of the disease is overexposure to asbestos. It most commonly affects the pleura, which lines the lungs and the chest cavity, but can also be found in the peritoneum (lining of the abdominal cavity) and the pericardium (sac surrounding the heart). Despite a common assumption that the disease is of the same origin as a smoker's lung cancer, there is no link between mesothelioma and smoking.

Symptoms of the disease may take as many as 20 to 50 years after exposure to become apparent. Different forms of mesothelioma present with different symptoms, but all are unpleasant. Coughing, shortness of breath, and chest pain resulting from a build-up of fluid in the pleural area are common symptoms of pleural mesothelioma.

Peritoneal mesothelioma may result in weight loss, ascites (a build-up of fluid in the abdomen), and abdominal pain. A person with peritoneal mesothelioma may also experience bowel obstruction, fever, anemia, or abnormal blood clotting. If the cancer metastasizes past the mesothelium, difficulty swallowing and swelling of the neck and face may occur.

In severe cases where many tumor masses are present, symptoms include: collapsed lung/lungs, blood clotting in the veins, blood clotting in the heart's arteries, severe bleeding in many organs, jaundice, a low blood sugar level, and severe ascites.

The symptoms of mesothelioma are shared by various other disorders, making this cancer a difficult disease to diagnose. When the above symptoms are presented, suspicion of mesothelioma is raised if the patient has a history of exposure to asbestos. A physical examination, chest x-rays, and lung-function tests are performed to rule out other possible problems. X-rays are used to determine if there is the pleural thickening that is normally seen after exposure to asbestos. A CAT scan and an MRI are performed if pleural thickening is detected, and tests are performed to detect abnormal cells in the pleural fluid. If abnormalities are found, a biopsy is performed to confirm results. A laparoscopy may be performed to determine if the cancer is in the abdomen.

Once the diagnosis has been made, doctors will assess the stage of the cancer. The stage is classified as "localized" if the cancer is limited to the membrane surface from which it originated, and "advanced" if it has spread farther.

The disease can be treated with surgery (but the average result is a 5 year survival rate of less than 10%), chemotherapy, radiation (used to relieve symptoms as the tumors are highly resistant to radiation), immunotherapy (which has produced varying results of success and disappointment), and heated intraoperative intraperitoneal chemotherapy (a procedure in which the surgeon removes as much of the tumor as possible before administering chemotherapy treatment immediately after, allowing 60 to 120 minutes to take effect before it is drained).