Asbestos and Mesothelioma
Overview of an Occupational Exposure and an Associated Lung Cancer
Jul 4, 2008
The substance called asbestos and the disease called mesothelioma are frequently heard together. Even so, this environmental exposure and its resulting conditions are fairly uncommon. When they do occur, the consequences can be a real challenge.
Asbestos
Asbestos is a group of long, thin glass fibers produced for various purposes, including but not limited to home-building materials like pipes and shingles, spray cans, textile materials like rope and tape, and brake linings. Once researchers discovered a clear association between asbestos and lung cancer, specifically bronchogenic carcinoma and malignant mesothelioma, production of asbestos stopped in the latter half of the 20th century.
By inhaling the fine silicate fibers of asbestos, the lungs become inflamed and develop permanent damage. Eventually, the person may experience difficulty with breathing (dyspnea), cough, and sometimes chest pain. Asbestos-related lung disease, called asbestosis, often has a long delay from exposure to onset of symptoms, often after at least 20 years. In addition, individuals with exposure to asbestos without concurrent smoking are already six times more likely to develop lung cancer than nonexposed individuals.
Mesothelioma
Mesothelioma is a rare malignant cancer originating from mesothelial cells, which line the pleura surrounding the lungs, the pericardium surrounding the heart, and the peritoneum surrounding the abdominal organs. The vast majority of mesothelioma cases occur in the pleura, with pericardial and peritoneal mesothelioma each seen in less than 10% of cases. Given the timeframe of its natural course, mesothelioma is generally found in older adults.
Mesothelioma classically presents with chest pain and dyspnea. Although these symptoms are not specific to only this condition, an occupational history mentioning industries with potential asbestos exposure, including shipyard work, mining, construction work, and manufacturing, raises clinical suspicion for mesothelioma. Methods to evaluate include thoracentesis to drain a pleural effusion, if present, and imaging studies like x-ray, computed tomography (CT), and magnetic resonance imaging (MRI) of the chest. However, to confirm mesothelioma, a physician must take a biopsy of the tumor and have it analyzed microscopically by a pathologist.
Options to treat mesothelioma include chemotherapy with cisplatin and other agents, radiation to relieve chest pain, and surgical removal of the affected pleura (pleurectomy) with or without removal of other lung tissue (pneumonectomy). Unfortunately, mesothelioma is associated with poor survival rates, even with intense treatment using all three modalities. In the best case scenario, only 14% of patients manage to survive for five years or more.
