Last Updated 05/07/2020
Author:Fabien Maldonado, MD, FCCP
Mesothelioma is a rare type of cancer. It typically develops in the thin membrane that separates the lung from the chest wall, called the pleura. It can also arise, less commonly, along the abdominal cavity inner (or peritoneal) lining. Mesothelioma can result in breathing difficulties, chest pain, and fever.
Mesothelioma often results from exposure to asbestos, a type of mineral fiber used in insulation.
Key facts about Mesothelioma
- Mesothelioma is a rare type of cancer.
- It usually starts in the pleura.
- It can also start in the peritoneum (lining of abdomen).
- The majority of cases of mesothelioma are caused by exposure to asbestos.
- Mesothelioma is not caused by smoking.
- A minority of patients exposed to asbestos will develop the disease.
There are approximately 3500 new cases of mesothelioma every year in the United States. This is a relatively small number compared, for example, with lung cancer (220,000 new cases per year in the United States). Mesothelioma is more common in men than in women.
In 80% of cases, mesothelioma is caused by exposure to asbestos. When asbestos fibers are inhaled into the lung, they can enter deeply because of their small size. The fibers accumulate near the pleura, irritating it. This irritation results in inflammation and abnormal spread of mesothelial (surface lining) cells. It can eventually lead to cancer many years after exposure (20 to 40 years, on average).
The abnormally growing cells produce tumor nodules on the surface of the lung. They also cause fluid buildup between the lung and the chest wall, which results in pain and shortness of breath.
There are other areas in the body with a lining similar to the pleura that can also—although rarely—be affected: the peritoneum, the lining around the heart (called the pericardium) and the scrotum.
How Mesothelioma affects your body
Mesothelioma, unlike other cancers, grows mainly along the surface of the lung and other surfaces of the chest. This results in pain from the attack on nerves in this area. It also causes shortness of breath from pressing on the lungs. Tumor nodules and fluid accumulate along the space between the lung and the chest wall.
Mesothelioma can spread to chest lymph nodes and invade the lung. However, it’s rare that it moves into other areas of the body. If mesothelioma progresses without treatment, it can cause death.
How serious is Mesothelioma?
Mesothelioma is a serious disease. The median survival time is only 9 months.
Research is being done, but there is currently no effective treatment for this disease.
However, care to help with symptoms and pain, called palliative care, can help. These therapies are tailored to individual needs.
There are important individual differences in how people are affected by the disease. Some people do much better than others.
Symptoms of Mesothelioma
Mesothelioma generally occurs in people who have been exposed to asbestos. These people were exposed sometimes 40 to 60 years before they are diagnosed with mesothelioma. In most cases, mesothelioma occurs at least 20 years after asbestos exposure. The extent of asbestos exposure and fiber deposits within the lung are generally less than the amount that causes asbestosis or other asbestos-related lung cancers.
Fewer than 5% of people exposed to asbestos develop mesothelioma. Sometimes, the diagnosis is made after a chest- X-ray is taken for other reasons. In these cases, people may not even have symptoms.
The lining of the lung is the most common site for the disease. Because of this, symptoms typically affect breathing. These symptoms tend to be late in the course of the disease and include:
- Shortness of breath;
- Chest pain that increases with the effort to breathe;
- Dry, persistent cough, typically without mucus production, that does not improve after several weeks or months;
- Wheezing or a whistling sound during breathing; and
- Frequent chest cold symptoms.
The progression of the cancer can also result in general symptoms described in other types of chronic illnesses, such as:
- Weight loss because of decreased appetite;
- General fatigue; and
- Low-grade fever.
When mesothelioma affects other areas of the body, symptoms change:
- When the lining of the abdomen is involved, you may notice:
- Abdominal swelling;
- Constipation or intestinal obstruction;
- Pain; or
- A lump or swelling may be felt in the scrotum when its lining is involved.
Rarely, the body may try to control the disease by producing antibodies to fight the cancer. These process lead to symptoms such as low blood sugar, blood clots in the legs or the lungs, and neurologic symptoms. These symptoms are called paraneoplastic, which means “associated with cancer.”
Contact your health care provider if you have these symptoms.
What causes Mesothelioma?
Researchers are still trying to understand what causes mesothelioma. When someone has been exposed to asbestos, the general thought is that asbestos fibers irritate the lining of the lung. This happens over a long period and causes inflammation. Eventually, it may cause cancer.
When someone is exposed to asbestos, the small fibers can easily be inhaled into the lungs. This increases the risk of developing mesothelioma, lung cancer, and a type of scarring lung disease called asbestosis.
What are the risk factors for Mesothelioma?
- Asbestos exposure. Asbestos is a mineral fiber. It is used in insulation and fire-resistant materials. Most people who develop mesothelioma because of exposure to asbestos were exposed during their work—called occupational exposure. Occupations associated with exposure to asbestos include mining, milling, electricians, plumbers, pipefitters, and insulators. Even people who have remodeled older homes or lived with workers may have been exposed to asbestos.
Living in a house that contains asbestos is not thought to be a cause of this disease. Many people with high exposure to asbestos fibers may have plaques in the lining of their lung. These can be seen in medical images. Though these plaques do not appear to be a sign of growing mesothelioma, they are often attacked by mesothelioma.
- Smoking is not a risk factor for mesothelioma. However, it is extremely important to quit smoking. Asbestos exposure increases the risk of mesothelioma and of lung cancer in general. Exposure to asbestos and continuing to smoke results in a very high risk of developing lung cancer.
- Other types of fibers. Other fibers, such as erionite, are thought to be responsible for mesothelioma, as well. Erionite has been identified in a specific region in Turkey called Cappadocia. It’s thought to be responsible for the high rate of mesotheliomas observed in that area.
- Age. The risk of developing mesothelioma increases with age because it takes a long time for mesothelioma to develop after asbestos exposure—sometimes 20 years or more. This time between exposure and malignancy is called latency.
- Other causes. Another cause is radiation therapy. Mesothelioma can occur in those who have received high doses of radiation to the chest for cancer, such as in the treatment of lymphoma. Certain rare genetic mutations are associated with mesothelioma, as well. These causes are much less common than asbestos exposure.
Sometimes, no cause can be identified.
Unlike breast cancer or lung cancer, there is no evidence that people who have been exposed to asbestos should be screened for the disease. However, when there is concern for mesothelioma, you must be screened.
What to expect
In general, individuals at risk for and with symptoms of mesothelioma are referred to a specialist in lung diseases, called a pulmonologist. You may first have a chest X-ray. Often, your doctor will order a computed tomography (CT) scan of your chest, as well. A chest CT is a 3-dimensional X-ray that shows lung and pleural abnormalities in detail. Your doctor may take small tissue samples, called biopsies, of these areas.
There are different ways to biopsy pleural lesions. Talk to your health care provider about which you may have. If you are diagnosed with mesothelioma, your health care team will do more testing to determine the type and extent of the disease. This information helps them decide the treatment that’s best for you.
How is Mesothelioma diagnosed?
- Chest X-ray. The chest X-ray may be normal or reveal signs of previous exposure to asbestos, called pleural plaques (thickened pleura). Sometimes, the chest X-ray shows fluid between the lung and the chest wall, or pleural effusion.
- Fluid drainage, called thoracentesis. When pleural fluid is seen, the next best step is to drain the fluid. This procedure is done to make sure there are no other causes of pleural effusions.
- Chest CT scan. This test allows a more detailed examination of the chest. It helps find the best site to biopsy. In addition, it can determine the extent of the disease. A needle biopsy may be performed, guided by CT images in the same procedure.
- Biopsy. A biopsy can be done in multiple ways. Talk to your provider about the type of biopsy you may need. Discuss how your health care team may determine your results.
- Staging of the disease. If you’re diagnosed with mesothelioma, your health care team will determine the stage or severity of the disease. This information helps guide treatment decisions.
- Additional testing. Your health care team may ask you to do tests, including lung function tests and blood test. These help determine what kind of treatment may work for you.
When should you see your health care provider?
Contact your provider if you:
- Have been exposed to asbestos at work or somewhere else;
- Have been diagnosed with frequent pneumonias; or
- Experience the symptoms listed in this information.
There is a currently a lot of debate on how mesothelioma should be treated. It’s important to be treated at centers with experience and expertise in treating this rare disease. The treatment may include various combinations of surgery, chemotherapy, and radiation therapy.
Your treatment combination depends on:
- The type and severity of the disease;
- How you respond to treatment; and
- Your preferences.
Approximately 20% of people are helped by surgery. Because mesothelioma is so rare, there has not been as much research to guide treatment decisions as in other cancers.
Living with Mesothelioma
Mesothelioma is often diagnosed when the disease leads to visible symptoms. Treatments to cure the disease are limited, but most of your symptoms can be managed to improve your quality of life.
Shortness of breath is a common symptom that interferes with quality of life in those with mesothelioma. It can be treated by removing fluid from the pleural space with a needle, placement of a drain, or sometimes surgery. Oxygen therapy and medications like morphine may also improve shortness of breath.
The progression of the cancer into the chest wall and nerve fibers may cause severe pain, leading to poor sleep. Pain is usually treated with medications. You may have poor nutrition and fatigue because of loss of appetite, nausea, progression of the cancer, or chemotherapy.
Palliative care is a key component of the care of mesothelioma. Doctors who specialize in palliative care can be a great value in treating symptoms and helping people and their loved ones make plans for the end of life. They should become part of the team as soon as possible after the diagnosis is established.
Managing mesothelioma means managing symptoms:
- Shortness of breath. Controlling pleural effusion is important for improving quality of life. There are many treatment options for controlling this fluid. Talk to your health care provider about which option is best for you.
- Pain. Pain is a major problem in the daily management of mesothelioma. Talk to your health care provider about which options are best for you. Palliative radiation therapy may help you with pain management in some circumstances.
- Nutrition and active lifestyle. It’s important to maintain an active lifestyle as much as possible. This can be difficult when pain and shortness of breath aren’t well managed. Lung rehabilitation with directed exercise may be helpful. Likewise, you may benefit from working with a nutritionist when poor nutrition is a concern.
Being diagnosed with mesothelioma is a major event. It can have emotional, physical, familial, and financial consequences. It’s important to establish strong relationships with a team of experts. This team can provide support and guidance in all aspects of the management of mesothelioma.
The Mesothelioma Applied Research Foundation is a nonprofit organization dedicated mesothelioma care, research, and education. It may be a useful resource for patients and their family members.
Questions to ask your health care provider
The diagnosis of mesothelioma can be overwhelming. It can affect all aspects of life in a profound way. Making notes before your visit and taking along a trusted family member or friend can help you through the first appointment with your provider. To make the best use of your limited time with doctors involved in your care, consider the following questions:
- What type of mesothelioma is it?
- Was the diagnosis based on tissue biopsy or fluid analysis (generally not enough to establish the diagnosis)?
- How extensive is the disease? Does it appear to be in one particular area, or does it affect lymph nodes, as well?
- Is the disease limited to the chest?
- What is the stage of the disease?
- What does it mean for me?
- What other tests may be done?
- Will my case be discussed in a multidisciplinary tumor board?
- What’s the goal of the treatment? Is the intent to cure me from the disease or manage its symptoms?
- How experienced is the team at managing mesothelioma?
- What are the side effects of the proposed treatment? How will it affect my quality of life?
- How long should I expect to be in the hospital? How long will the treatment last? What will it be like?
- How much will this cost me? Can you help me identify somebody who might be able to answer these questions?
- How much experience do you have treating patients like me?
- Where can I find a center with a multidisciplinary team that specializes in the management of mesothelioma? Can you recommend a particular team?
- Am I a candidate for any clinical trials?
- What are my options for palliative care to address my symptoms of shortness of breath and pain?
It’s important that you ask any questions you have. Your care team wants to help you be informed and make the best decisions.