You may not be familiar with the word mesothelioma, but you’re probably familiar with what it is. Malignant mesothelioma is a type of cancer that develops primarily after exposure to asbestos. The good news is that it’s now a rare cancer, affecting only about 3,000 people per year in the U.S.
[See: 7 Things You Didn’t Know About Lung Cancer.]
What Is Malignant Mesothelioma?
“Malignant mesothelioma is a cancer of the pleura, or the lining around the outside of the lung,” says Dr. Nathan A. Pennell, an associate professor in the Department of Hematology and Medical Oncology and director of the Lung Cancer Medical Oncology Program at Cleveland Clinic. “The pleura is a lubricating layer that helps the lungs move [in the chest] without friction.” Malignant mesothelioma can also form in the lining of the abdomen or, in very rare cases, around the heart or testicles.
Like lung cancer, people with malignant mesothelioma often present with chest symptoms, says Dr. David Gerber, associate professor at UT Southwestern Medical Center. “They have shortness of breath, coughing, pain from the pleural lining.” Interestingly, the lungs themselves don’t actually feel pain, Gerber says.
Malignant mesothelioma is more common in men (80 percent of patients are men) because they traditionally held jobs in occupations where they were exposed to asbestos, such as construction and shipbuilding. Asbestos was widely used from the early 1900s until the 1970s, when we finally accepted the scientific evidence about the dangers of asbestos and limited its use. It was frequently used for insulation and can still be found in old buildings. Unfortunately, asbestos is still widely used in the developing world, which will continue to put people at risk for this serious disease.
Asbestos is comprised of tiny fibers that you can easily inhale into your lungs, where they remain permanently, causing chronic irritation of the pleura. Over several decades, this irritation can create a cascade of events that cause cells to eventually become cancerous and form malignant mesothelioma.
Fortunately, Gerber says, the incidence of malignant mesothelioma in the U.S. is decreasing and, in fact, peaked about 10 years ago. Gerber says if you’re exposed to asbestos, you have a 5 to 10 percent likelihood of developing malignant mesothelioma. People who live with someone who works with or near asbestos are also at increased risk.
Although most cases of malignant mesothelioma are linked to asbestos exposure, Gerber says that in rare cases, prior radiation exposure to the chest, for example for cancer treatment, can also cause the disease. Despite the strong link between cigarette smoking and lung cancer, smoking does not seem to raise the risk for malignant mesothelioma.
There are cancers of the pleura that are not malignant mesothelioma — although they present as if they are — and that don’t appear to be linked to asbestos exposure the way malignant mesothelioma is. Most often, these pleural cancers are actually malignancies, other cancers that have spread to the pleura. Usually, these malignancies are from cancers of the lung and breast or malignant lymphoma.
[See: What Not to Say to Someone With Lung Cancer.]
Treating Malignant Mesothelioma
Most cases of malignant mesothelioma grow locally and remain largely confined in the chest, in the pleural space and the lymph nodes, Gerber says.
Unlike other cancers, however, the tumor stage at diagnosis doesn’t tell you how well you’re likely to do with treatment. Unfortunately, malignant mesothelioma is almost always fatal, Pennell says. “It’s rare for it to be cured.”
Part of the problem is that malignant mesothelioma is usually diagnosed at an advanced stage, typically in older men. The other problem is the way the cancer grows in the chest. “It grows in a lining that covers nearly one-quarter of the body,” Pennell says. “It’s [usually] impossible to remove it [surgically] even if it hasn’t spread.” Treatment always consists of chemotherapy and may also include surgery and radiation. Pennell says some of the newer immunotherapy drugs may prove beneficial in treating malignant mesothelioma as well.
“It’s a tough disease to study,” Pennell says. “There are not too many people with it at any one time. Many [who have it] are not well enough to go into experimental treatments.”
[See: 7 Innovations in Cancer Therapy.]
If you live in an older home that may still have asbestos, don’t worry. Pennell says unless you disturb the asbestos, you’re not at risk for exposure. If you, for example, replace an old boiler that’s wrapped with asbestos, it’s important that you hire professionals who can take appropriate precautions and safely remove the asbestos.
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What to Know About Malignant Mesothelioma originally appeared on usnews.com
