Malignant mesothelioma is a rare and aggressive cancer which is almost always caused by asbestos exposure. This devastating disease attacks the mesothelium, the protective membrane that covers the lungs, abdomen, and heart.
Although you may never have heard of the mesothelium, you could not function without it. This thin layer of protective tissue lubricates and protects the internal organs, and allows them to move easily inside the chest and abdomen. Without the mesothelium, your lungs, heart, and stomach could not expand and contract freely.
When a person has mesothelioma, their mesothelial cells become malignant and grow out of control. As the tumor expands, it produces a fluid called a pleural effusion, which builds up in the chest or abdomen and presses on the surrounding organs. Eventually, the cancer cells may metastasize into the chest wall, lymph nodes, lungs, liver, or even the brain.
An estimated 2,000 to 3,000 people in the United States are diagnosed with mesothelioma each year. Tragically, there is still no known cure. However, the number of treatment options is steadily increasing. If the cancer is caught early enough and treated effectively, a patient’s prognosis can be significantly improved. Cancer researchers are also working to develop innovative new therapies that may dramatically improve outcomes for mesothelioma patients in the future.
Asbestosis is a nonmalignant lung disease caused by inhalation of asbestos dust. When someone is exposed to asbestos for a prolonged period, he or she will breathe in millions of tiny asbestos fibers. Over time, these microscopic fibers become lodged in the lung tissue.
Because these fibers are so long and sharp, the body’s normal defenses are unable to eliminate them. The asbestos fibers remain in the lungs, and cause inflammation and scarring in the alveoli. Over time, the scar tissue accumulates. This is a condition known as pulmonary fibrosis, which makes it impossible for the lungs to function properly. The lungs become stiff, and can no longer expand and contract normally. In addition, the damaged lung tissue loses its ability to transfer oxygen into the bloodstream.
As the disease progresses, lung capacity diminishes, and the patient finds it increasingly difficult to catch his or her breath. Besides experiencing shortness of breath or dypsnea, the patient may also have other symptoms such as coughing, chest pain, tightness in the chest, and abnormal growths or clubbing of the fingers.
Asbestosis is a disease that worsens over time. In its advanced stages, it is a disabling condition, and can even be fatal. Like mesothelioma, asbestosis has a long latency period. Typically, symptoms do not appear for at least 15 to 20 years after the first exposure to asbestos.
If you are diagnosed with asbestosis, it is very important that you stop smoking immediately. Asbestosis puts you at heightened risk for lung cancer and mesothelioma, so be sure that you visit your doctor for regular check-ups. You should also be sure to get regular chest x-rays to monitor the condition of your lungs.
Mesothelioma is not the only type of cancer caused by asbestos. Occupational exposure to asbestos is also associated with a higher incidence of lung cancer, particularly among smokers.
Although many people assume that lung cancer is primarily caused by cigarette smoke, in fact smoking and asbestos exposure have a synergistic effect. That means they work together to increase the risk of lung cancer much more than either smoking or asbestos alone. Smokers who have been exposed to asbestos are 50 to 90 times more likely to get lung cancer than smokers who were never exposed to asbestos.
Like most other asbestos diseases, asbestos-induced lung cancer generally has a significant latency period. Usually it takes 20 to 35 years or more to develop lung cancer after the first exposure to asbestos.
The most common symptoms of lung cancer are a worsening cough or a cough that won’t go away, and a change in breathing. Other symptoms may include:
- Shortness of breath
- Persistent chest pains
- Loss of appetite
- Weight loss without a known cause
- Repeated lung infections such as bronchitis or pneumonia
- Coughing up blood
Asbestos exposure has also been associated with certain other cancers, including colon cancer, stomach cancer, cancer of the esophagus and larynx, and ovarian cancer. However, the evidence linking asbestos to these other forms of cancer is much weaker than the overwhelming evidence that asbestos causes both lung cancer and mesothelioma.
Pleural plaques are a nonmalignant condition caused by asbestos. A plaque is a thickened patch on the pleura, which is a tissue lining the chest cavity. Sometimes, over time, these plaques become calcified and are known as “calcified pleural plaques.”
Pleural plaques are not cancerous, nor do they cause cancer. However, they are considered to be a “marker” of asbestos exposure. If you are diagnosed as having pleural plaques, this is evidence that you have probably been exposed to asbestos. This is especially true when the plaques are bilateral, meaning that there are plaques on the pleura of both lungs. Like other asbestos-related diseases, pleural plaques have a significant latency period. It takes at least seven years to develop pleural plaques after your first exposure to asbestos.
Pleural plaques are quite common and generally do not require any treatment. In most cases, the plaques cause no symptoms. In some cases, however, pleural plaques can cause a dull or pleuritic chest pain. In severe cases, they can restrict the expansion of the lungs, causing shortness of breath or dypsnea.
Asbestos can also cause pleural thickening, which is a thickening of the lining of the lungs, with or without pleural plaques. Like pleural plaques, pleural thickening is a noncancerous condition which is known to be a “marker” of asbestos exposure. In severe cases, pleural thickening can also cause restriction and shortness of breath.
If you are told that you have pleural plaques or pleural thickening, it is important to stop smoking. Because the plaques are a marker of asbestos exposure, you are at a heightened risk for lung cancer and mesothelioma. You should also see your doctor for regular check-ups, and have a chest x-ray at least every two to five years. You may also need to have a regular lung function test.