A type of cancer occurring in the mesothelium which is the thin tissue layer covering internal organs, mesothelioma is aggressive and potentially fatal. Mesothelioma can be treated, but many patients with the disease do not receive a positive prognosis. Primary types of mesothelioma include pleural mesothelioma around the lungs and peritoneal mesothelioma in the abdomen. Pericardial mesothelioma around the heart and mesothelioma of tunica vaginalis, the tissue that covers the testicles, are both rare but known to occur.
Definition & Facts
The mesothelium is a thin protective membrane lining most of the internal organs. This membrane is where mesothelioma occurs, with 75 percent of all cases beginning in the chest cavity. The abdominal cavity is another area where this aggressive form of cancer often starts.
A mesothelioma diagnosis often occurs only after the disease has become advanced. Only between five and 10 percent of mesothelioma patients survive five years after diagnosis, with most dying as a result of pneumonia or respiratory failure. Other patients may suffer from a bowel obstruction due to tumor growth through the diaphragm or cardiac complications from growth into the pericardium or even the heart itself. Malignant cancer cells often metastasize to other body parts.
Symptoms & Complaints
- Pain in the chest under ribs
- Shortness of breath
- Painful cough
- Odd tissue lumps under skin on chest
- Unexplained weight loss
Mesothelioma of the abdomen's tissues, known as peritoneal mesothelioma, may cause the following symptoms:
Pericardial mesothelioma of heart tissues can cause difficulty breathing and chest pains. Mesothelioma of tunica vaginalis, affecting the testicular region, is often discovered through swelling or a mass on a testicle.
While some may have a genetic predisposition towards developing mesothelioma, asbestos exposure is the primary risk factor for mesothelioma. This fibrous mineral material used in construction, automotive and industrial environments for heat resistance can become airborne and may be swallowed or inhaled. About 75 percent of mesothelioma cases can be directly linked to asbestos exposure in occupational environments. Even members of workers' families can be exposed to mesothelioma-causing asbestos due to dust carried home on the workers' hair or clothing.
Asbestos was once commonly used in commercial and public building construction. This included schools, libraries and other high exposure properties. Health risk is elevated when damage to the asbestos occurs, the material is disturbed, or when it is improperly removed. Mesothelioma is more common among certain populations due to common fields of work. Those fields include:
- Factory workers
- Railroad workers
- Insulation manufacturers
- Insulation installers
- Automotive workers
- Gas mask manufacturers
- Ship builders
- Construction workers
- Navy military members or contractors
Mesothelioma has also been reported to occur from exposure to the following:
- Zeolites, minerals related to asbestos in regions like areas of Turkey
- Radiation, after high doses of delivery to chest or abdomen after thorium dioxide injections
- SV40 viral infection
Diagnosis & Tests
To diagnose mesothelioma, a tissue sample is removed through biopsy. A pathologist then views the sample under a microscope to make a diagnosis. Biopsies are usually ordered after patients experience fluid buildup around their lungs, chest pain, pain or swelling in their abdomen or shortness of breath. X-rays and CT scans are also often ordered by doctors to enable diagnosis. Other tests to help diagnose mesothelioma include:
- Thoracoscopy in which the inside of the chest is viewed through a thoracoscope
- Peritoneoscopy in which the inside of the abdomen is viewed using a peritoneoscope
Treatment & Therapy
One or more forms of treatment may be used to treat this aggressive cancer. There are three widely used treatment methods for malignant mesothelioma, including:
Surgery will consist of removing cancer growth and possibly even affected tissues, such as chest lining, abdomen lining, diaphragm tissue, heart lining, or a lung. When fluid has collected in the abdomen or chest due to mesothelioma, the doctor may insert a needle into the region to drain the fluid. In the chest, this procedure is known as a thoracentesis. It is called a paracentesis when the fluid is extracted from the abdomen. When fluid persistently collects, the doctor may insert a tube in the chest for delivery of drugs to prevent this accumulation. Researchers are working to find new methods of treatment for mesothelioma.
Prevention & Prophylaxis
Older homes constructed prior to the 1980s frequently have insulation containing asbestos and similar materials. Before living in or renovating such properties, it is important to have an expert inspect the home to identify any asbestos and vulnerability for exposure. These experts may test the air quality for their report.
While presence of asbestos creates greater risk than not being exposed at all, the material can still be safe to live around as long as it is not disturbed or damaged. Homeowners or other building owners with asbestos insulation in their property should not drill into the structure or remodel without the help of a qualified contractor with asbestos safety experience.
Federal laws are now in place to regulate use of asbestos in products. But not all uses have been banned in the United States. The government does regulate how pre-existing asbestos is handled and workers are protected from exposure in order to ensure greater safety from mesothelioma.