Mesothelioma is a rare form of cancer that affects cells found in the mesothelium, a protective membrane surrounding the majority of the body’s internal organs. The cells that make up this membrane protect the organs by making a special fluid that allows the organs to move and, in particular, help the lungs to move during breathing.
The vast majority of people who develop this deadly disease have inhaled asbestos particles, often through their jobs. In fact, a history of asbestos exposure in the workplace is reported in approximately 70 to 80 percent of all mesothelioma cases. In addition to mesothelioma, the inhalation of the deadly mineral fibers can cause lung cancer and asbestosis. The World Health Organization estimates that asbestos-related diseases kill approximately 107,000 people around the world each year.
Asbestos was originally prized by the ancient Greeks and Romans due to its resistance to fire and use as an insulator. Use of the mineral increased rapidly during the 19th century, particularly during the Industrial Revolution. By the mid-1930s, however, it was known that exposure to asbestos could cause a range of serious illnesses.
Mesothelioma comes in three varieties:
- Pleural: most common (75% to 80% of diagnosed cases), originates within the chest and impacts the lungs
- Peritoneal: second most common (15% to 20% of diagnosed cases), originates in the abdomen and can involve the testicles, or spread to liver, spleen or bowel
- Pericardial: very rare (less than 2%), originates around the heart
While mesothelioma is relatively rare, approximately 2,500 new cases of mesothelioma are diagnosed in the United States each year. And unfortunately, the average survival time of those with malignant forms of the disease is ten to fourteen months. The prognosis for a long life expectancy is not good even when symptoms appear early and treatment begins quickly.
Other Mesothelioma Facts
- It usually takes a long time before symptoms of mesothelioma appear (on average 20 to 50 years)
- There is a difficulty in diagnosing mesothelioma because its symptoms are common to many types of infections and cancers
- There is often a challenge of putting together the puzzle pieces for an accurate diagnosis
- Mesothelioma occurs more often in men than in women
- The risk of developing mesothelioma increases with age, although anyone can get mesothelioma
- Treatment depends on cancer location, the patient’s general health and disease stage
- Standard treatment options include radiation therapy, surgery and chemotherapy. In some instances, these are combined
While treatments are available for some people with mesothelioma, they are mostly used to improve the quality of life of people whose survival prospects are typically measured in months and not years.
The only read mesothelioma causes come from asbestos fibers that enter the body in the air we breathe. Like other dust particles that we breathe, most of the asbestos fibers are stopped long before they enter the small airways of the lungs. For example, we sometimes choke when we enter a dusty room. We literally cough up the mucus that contains most of the irritating substances. However, because asbestos fibers are so small and thin, many of them pass all the way down to the small airways and air sacs that fill the lung.
Once the fibers are inside the lungs, the body’s defense mechanisms try to break them down and remove them. However, many fibers still remain in the body and are potential disease-causing agents:
- Each fiber is a foreign body and inflammations develop as our bodies try to neutralize, break down or move the sharp, irritating asbestos fibers, just like splinters that get stuck under the skin.
- These processes lead to development of the various kinds of asbestos-caused diseases.
Symptoms of mesothelioma usually appear between 20 and 50 years after the first exposure to asbestos. Recognizing early symptoms of malignant mesothelioma may aid in diagnosis. Many mesothelioma symptoms mimic symptoms of other, less serious illnesses, delaying diagnosis even further.
Malignant mesothelioma is diagnosed in one of three forms: pleural, peritoneal, or pericardial.
Pleural Mesothelioma Symptoms
Primary symptoms of pleural—lung membrane—mesothelioma include:
- Shortness of breath
- Coughing, wheezing or hoarseness
- Blood in coughed up fluid
- Fatigue or anemia
- Chest pain due to accumulation of fluid around the lungs, in the pleural space
Pleural mesothelioma symptoms are shared by many other illnesses—if standard treatments for bronchitis, the flu and pneumonia do not bring relief, your doctor should take steps to rule out mesothelioma as a possible cause.
Peritoneal Mesothelioma Symptoms
Primary symptoms of peritoneal—abdominal lining—mesothelioma include:
- Abdominal pain
- An abnormal buildup of fluid in the abdomen (ascites)
- Bowel obstruction
- A mass in the abdomen
Symptoms of peritoneal mesothelioma often do not appear until the advanced stages of the illness, and even then resemble symptoms of other illnesses.
Pericardial Mesothelioma Symptoms
Primary symptoms of pericardial—heart membrane—mesothelioma include:
- Heart palpitations or irregular heartbeat
- Chest pain
- Heart murmur
- Difficulty breathing, even at rest or lying down
- Fever or night sweats
Pericardial mesothelioma makes up fewer than six percent of all recorded mesothelioma cases. Like pleural and peritoneal mesothelioma, the symptoms of pericardial mesothelioma closely resemble the symptoms of other heart conditions, usually delaying diagnosis.
The importance of mesothelioma screening
The National Cancer Institute’s definition of screening for cancer is the examination or testing of people for early signs of certain type of cancer even though they have no symptoms – this is the best way to achieve a diagnosis as early as possible. Early detection and diagnosis is particularly important for people with historical exposure to asbestos due to the latency period (up to 50 years) before which symptoms of malignant mesothelioma cancer may become apparent.
Sometimes more invasive tests are required which may include screening methods for diagnosis of asbestos-related diseases using various imaging tests. In addition to regular X-rays, imaging tests include:
- Computed Tomography / CT Scan. Computed tomography is a recently developed special radiographic technique. Usually a spiral CT scan, it produces a clear cross-sectional image allowing a radiologist to see distinct aspects of the lung or pleura not readily apparent from a standard X-ray image.
- Magnetic resonance imaging (MRI)
- Positron emission tomography (PET)
Mesothelioma Screening Methods to Identify Asbestos-Related Disease
After a preliminary physical examination, your doctor may employ the following procedures to find out more about your condition:
- Thoracoscopy – A scope is used to look inside your chest cavity. A small cut will be made in your chest and a small piece of tissue may be removed for examination (biopsy) during the procedure. While you may feel some pressure, there is usually no pain.
- Peritoneoscopy uses another specialized instrument that allows for examination inside your abdomen. A scope is inserted into an opening made in the abdomen, and a biopsy specimen may also be taken.
- If the presence of fluid is indicated by either of these procedures, the doctor may drain it by inserting a needle into the affected area. Removal of chest fluid is called thoracentesis. Removal of abdominal fluid is call paracentesis.
What is Asbestos?
Asbestos is the name for a group of naturally occurring silicate minerals that can be separated into fibers. The fibers are strong, durable, and resistant to heat and fire. They are also long, thin and flexible, so that they can even be woven into cloth.
Because of these qualities, asbestos has been used in thousands of consumer, industrial, maritime, automotive, scientific and building products. During the twentieth century, some 30 million tons of were used in industrial sites, homes, schools, shipyards and commercial buildings in the United States.
There are several types of asbestos fibers, of which three have been used for commercial applications:
- Chrysotile, or white, comes mainly from Canada, and has been very widely used in the US. It is white-gray in color and found in serpentine rock.
- Amosite, or brown, comes from southern Africa.
- Crocidolite, or blue, comes from southern Africa and Australia.
Amosite and crocidolite are called amphiboles. This term refers to the nature of their geologic formation.
Other asbestos fibers that have not been used commercially are tremolite, actinolite and anthophyllite, although they are sometimes contaminants in asbestos-containing products. It should be noted that there are non-fibrous, or non-asbestiform, variants of tremolite, anthophylite and actinolite, which may not have the same adverse health consequences that result from exposure to commercial forms of asbestos.
Why is asbestos still a problem?
Asbestos is still a problem because a great deal of it has been used in the United States and elsewhere, because many asbestos-containing products remain in buildings, ships, industrial facilities and other environments where the fibers can become airborne, and because of the serious human health hazards of inhaling the fibers.
Many Americans believe that use of asbestos in products was banned years ago. The fact is that asbestos-containing products are still being imported and sold in this country, continuing to endanger people who may come in contact with such products. A majority of these products are imported from Canada and Mexico, two countries where asbestos is still used. Further, not all imported products are clearly labeled with proper content information.
What is common to many asbestos products is that they were (are) used to contain heat (i.e. thermal insulation.) It is impossible to list all of the products that have, at one time or another, contained asbestos.
Common asbestos products:
- insulating cement
- insulating block
- asbestos cloth
- packing materials
- thermal seals
- refractory and boiler insulation materials
- transite board
- asbestos cement pipe
- fireproofing spray
- joint compound
- vinyl floor tile
- ceiling tile
- acoustical textures
- duct insulation for heating, ventilation and air conditioning (HVAC) systems
- roofing products
- insulated electrical wire and panels
- brake and clutch assemblies
Some of these products contained a very high proportion of asbestos, while others contained small amounts.
Exposure to asbestos fibers can cause asbestos-related diseases including malignant mesothelioma and other cancers. A potentially dangerous asbestos exposure can result from very small fibers at low exposure levels. Most such exposure would likely have occurred prior to the 1980s, but the latency period can be up to 50 years for most asbestos-related cancers to develop.
Many people have come into contact with asbestos fibers at their jobs. This is occupational exposure. There is also a risk to the family members of those working in at-risk occupations; this exposure is called paraoccupational exposure. Approximately 70% to 80% of the cases of mesothelioma are believed to be the direct result of easily identified occupational or paraoccupational exposure to asbestos fibers.
A third group of people are also at risk, not from their job, but from where they live. Sites likely to have asbestos include refineries, power plants, factories, shipyards, steel mills and demolished buildings. Those who live nearby can be exposed by the release of asbestos fibers that contaminate their residential neighborhoods.
Specific Industries and Occupations with Asbestos Exposure Risk
Industries / Job Locations:
- Asbestos product manufacturing (insulation, roofing, building, materials)
- Automotive repair (brakes & clutches)
- Oil refineries
- Power plants
- Shipyards / ships
- Steel mills
- Automotive mechanics
- Boiler makers
- Building Inspectors
- Hod carriers
- Iron workers
- Maintenance workers
- Merchant marines
- Sheet metal workers
- Steam fitters
- Tile setters
- U.S. Navy veterans