Asbestosis is a chronic inflammatory lung disease caused by the inhalation of asbestos fibers. Asbestos is a mineral fiber that has been used in building materials, insulation and automotive parts. The Environmental Protection Agency banned several, but not all uses of asbestos in 1999. The Agency for Toxic Substances and Disease Registry, or ATSDR, reports that by the year 2030 asbestos-associated deaths may exceed 200,000 in the United States.
Asbestosis
Asbestosis is not a type of cancer, but a progressive buildup of scar tissue in the lungs, also called pulmonary fibrosis. Once inhaled, the asbestos fibers can lodge in lung tissue and cause an inflammatory response, in which cells of the immune system attempt to rid the lungs of the fibers. The cells, called macrophages, fail to dispose of the fibers and the ensuing chronic inflammation leads to the replacement of functioning lung tissue with non-functioning scar tissue. In rare instances asbestosis may progress to lung cancer, or mesothelioma, which is a specific type of cancer that affects the membranes surrounding the lungs and other organs.
Cancer
Asbestos exposure may cause different types of lung cancer, including adenocarcinoma, oat-cell carcinoma and squamous cell carcinoma. A study in the journal, "Pathology" reported the incidence of lung cancer in persons occupationally exposed to asbestos is between 4 and 12 percent. Mesothelioma is a deadly, malignant cancer that most often originates in the lining of the lungs, but it may appear in the lining of the heart or abdomen. Mesotheliomas are almost entirely attributed to asbestos exposure. The National Cancer Institute states that approximately 3000 people died from mesothelioma in the year 2000.
Diagnosis
The ATSDR reports that patients with asbestosis display fine, irregular opacities with honeycombing on lung radiographs. The diagnostic criteria developed by the American Thoracic Society, or ATS, for asbestosis are chest X-rays that document plaques in the lungs, decreased respiratory function, a history of occupational or environmental exposure to asbestos and the exclusion of other causes of pulmonary fibrosis.
Symptoms
The onset of symptoms of asbestosis may take up to 20 years or more after exposure, and the severity is dependent on the length of exposure and the structure of the inhaled asbestos fibers. In patients with asbestosis, respiratory function, measured by lung function tests, such as vital capacity and total lung capacity, is decreased causing shortness of breath, coughing and chest pain. Patients with asbestosis do not normally die from the disease, but the ATSDR reports that 38 percent die from lung cancer, 9 percent from mesothelioma, and 32 percent from other causes.
Treatment
The "Asbestos Network" states that the symptoms of asbestosis may be treated, but the disease is not curable. Bronchodilators, inhaled, or oral medications are used to open the bronchial tubes in order to alleviate shortness of breath. Humidifiers are used to treat chronic cough, and acetaminophen or ibuprofen are used to reduce chest pain. Patients with advanced asbestosis may be treated with oxygen. Patients with lung cancer or mesothelioma may be treated with surgery, chemotherapy, radiation, photodynamic therapy, immunotherapy or a combination of these. Photodynamic therapy is an experimental treatment that uses light-sensitive drugs and laser light to kill cancer cells.
