Mesothelioma is a form of cancer that originates in one of the membranes surrounding internal organs. It can occur in the membrane surrounding the lungs, the heart, or the abdominal organs.

Is it serious?

It is very serious. It is incurable and ultimately fatal.

Mesothelioma is frequently not detected in time to be treated surgically. In those cases, radiation and chemotherapy can help slow the cancer’s growth, but survival after diagnosis is often just one or two years.  When it is detected early enough to be treated with surgery as well as chemotherapy and radiation, survival rates can improve to five years or more.

What causes mesothelioma?

The only known cause of mesothelioma is repeated and/or heavy exposure to asbestos dust.

What is asbestos?

Asbestos is a mineral that can be separated into fibers and woven into a cloth-like material.  It can also be mixed with other materials into a slurry, and applied as a coating or formed and dried into shapes.  Asbestos is used in over 3,000 products because it is very durable, fire-proof and an effective insulator for heat, sound, and electricity.

How would someone be exposed to asbestos?

Asbestos itself is not what is hazardous.  It is the fine, fiber-like particles present in asbestos dust that can get into the lungs and ultimately cause mesothelioma.  Millions of people have been exposed to asbestos dust at work where asbestos-containing products are manufactured or where asbestos-containing products are used. Some people have been exposed at home when a family member unknowingly brings asbestos dust home on clothing, or when asbestos products in the home are disturbed or begin to deteriorate.

How much asbestos exposure does it take to get mesothelioma?

First of all, we should note that only a few percent of people who are exposed to asbestos dust acquire mesothelioma. Of those who do acquire the disease, they have typically been exposed to some level of asbestos dust in the air for years.  There is one reported case, however, of a man whose exposure consisted of several days of sawing up asbestos panels.

Are asbestosis and mesothelioma the same disease?

No. Although both are caused by inhaling asbestos dust, asbestosis is not a cancer. It is a condition caused by damage to the lungs from asbestos fibers. 

How long does it take to get mesothelioma?

Mesothelioma is typically not diagnosed until 15 to 40 years following initial exposure.

What are the symptoms of mesothelioma?

Symptoms that can occur with each of the different types of mesothelioma are:

• Chest or abdominal pain
• Breathing problems
• Sleeplessness, loss of appetite and weight loss

Additional symptoms depend on which internal membrane is affected, but may include gastrointestinal problems or heart problems.

Why are lawyers so interested in people with mesothelioma?

People being diagnosed with mesothelioma now were exposed to asbestos dust years ago when manufacturers had little incentive to protect people from asbestos, even though it was known then to be harmful. Therefore, in almost every case of mesothelioma, some company or another can be shown to be negligent in allowing the exposure hazard to exist.  Because of that negligence, lawyers can sue on the victim’s behalf and obtain compensation for them. 

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• Occupational Exposure
• Secondary Exposure
• Outdoor Environments
• Indoor Environments

Occupational Exposure

The exceptionally high rate of mesothelioma cases among workers in asbestos industries as compared to workers in other industries is well documented.  Contrary to what many people assume, however, asbestos is not banned in the U.S. and is still present in an extremely wide variety of products. Manufacturing, installing or removing asbestos-containing products such as these carries the greatest risk for occupational asbestos dust exposure.

• Cement products
• Flooring
• Wallboard and patching compounds
• Insulation
• Friction products
• Adhesives
• (See epa.gov for a more detailed list.)

Before OSHA began regulating asbestos exposure in the 1970s, millions of workers suffered prolonged exposure to asbestos. Over the ensuing 30 years, these laws have been gradually strengthened and extended to workers in all industries.  Sadly, however, the rules regulating workplace exposure to asbestos are not uniformly implemented or enforced, even today. This continues to leave workers in some industries at serious risk.

The percentage of exposed workers who will develop malignant mesothelioma is very small, but they still number between 2,000 and 3,000 new cases per year.  Because the disease can take as long as 40 years to develop, experts expect no decrease in the number of cases over the next few decades.

Secondary Exposure

The dangers of asbestos are not limited to workers in asbestos-related industries. Family members living with asbestos workers are also exposed to hazardous levels of dust the worker brings home on clothes and other articles. 

Similar to second-hand smoke, secondary exposure can be enough to induce disease. Several studies estimate that as many as one-quarter of mesothelioma cases are family members of asbestos workers.

Outdoor Environments

Another source of exposure unrelated to occupation is from high-levels of asbestos dust in the outdoor environment.  This occurs near plants and industrial centers where asbestos products are used or manufactured, and in areas where naturally occurring asbestos is found in local rock formations.

In one California study, a database of nearly 3,000 mesothelioma deaths over a 9-year period was cross-referenced to known locations of naturally occurring asbestos deposits in Northern and Central California. After adjusting for sex, age and occupational risks, the researchers concluded the incidence of mesothelioma dropped 6% for every six miles farther away a person lived from natural asbestos formations.

Other studies show a similar correlation between increased risk of mesothelioma and living close to asbestos manufacturing facilities or mining operations.  Some studies even substantiated higher risk in living on the predominantly downwind side of the asbestos source.

Indoor Environments

Before the Environmental Protection Agency (EPA) first regulated asbestos in 1971, it was an extremely common substance in many building construction materials. It was used in or added to hundreds of products to increase durability, fire-resistance and sound and heat insulation qualities. In the mid-1970s, government-required inspections of schools and public buildings uncovered significant amounts of asbestos present in pipe coverings, fireproofing, soundproofing and insulation.

The mere presence of asbestos in building materials is not a hazard, however.  The danger exists only when asbestos dust is released into the air because of deterioration, or by cutting, sawing, drilling or other disturbance. Even though federal laws in the 1980s required and helped fund identification and cleanup of asbestos hazards in schools and public buildings, asbestos has not been completely eradicated.

A review of National Center for Health Statistics data for 2003 revealed that schools and hospitals ranked 3rd and 4th among all businesses reporting mesothelioma cases. Given that it takes up to 40 years after exposure to develop mesothelioma, these victims were probably exposed in the 1960s.

Looking forward, school and hospital workers exposed to asbestos during the 1980s, possibly during cleanup efforts, will not begin exhibiting mesothelioma symptoms until the 2010s or 2020s.

In theory, the same sorts of risks can exist in private homes if asbestos containing materials are deteriorating or disturbed, but we lack statistical data to confirm how frequently this occurs.

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The mesothelium surrounding the lungs is called the pleura.  Others are the peritoneum (surrounding the abdominal organs), and the pericardium (surrounding the heart).  Another is the tunica vaginalis, which is an extension of the peritoneum and surrounds the testicles.

Common Symptoms of Mesothelioma

Because  pleural, peritoneal and pericardial mesothelioma are in different locations, symptoms can vary between these types.  But some symptoms are common to all three.

Chest or Abdominal Pain

One of mesothelioma’s symptoms is excessive fluid buildup between the layers of the mesothelium.  When this occurs in the pleura, it’s called pleural effusion. The pressure of this accumulated fluid around the lungs can cause moderate to severe chest pain.

When mesothelioma occurs in the peritoneum or pericardium, then peritoneal or pericardial effusion can also cause chest or abdominal pain.

Respiratory Symptoms

Pleural effusion caused by pleural mesothelioma can create other symptoms in addition to pain. The pressure of the excess fluid against the lungs can cause shortness of breath, and the inability of the lungs to expand fully can result in a persistent cough.

The pressure of fluid accumulation in the chest or abdomen from peritoneal or pericardial mesothelioma can also cause similar breathing difficulties and coughing.

Sleeplessness, Loss of Appetite and Weight Loss

Difficulty breathing and recurring pain can contribute to sleeplessness, which in turn can lead to loss of appetite and weight loss.

Pleural Mesothelioma – Additional Symptoms

Additional symptoms that may be present with pleural mesothelioma include:

• Hoarseness or husky voice
• Difficulty swallowing

Peritoneal Mesothelioma – Additional Symptoms

Because of a peritoneal tumor’s location in the abdomen, a variety of gastric-related symptoms may occur:

• Nausea
• Vomiting
• Diarrhea or constipation
• Abdominal swelling
• Fever
• Weakness
• Anemia

Pericardial Mesothelioma – Additional Symptoms

The pericardial tumor being located adjacent to the heart can cause:

• Extreme fatigue after minor physical activity
• Heart palpitations

Testicular Mesothelioma

Mesothelioma that strikes the tunica vaginalis – the membrane surrounding the testicles – is referred to as testicular mesothelioma.  This type of tumor rarely causes any symptoms.  It is typically discovered only when a testicular lump becomes evident. This type of cancer is so rare, only about 100 cases have ever been documented.

Diagnosis

All of the symptoms above are common to many other diseases and medical conditions which occur far more frequently than mesothelioma. Exhibiting these symptoms doesn’t necessarily indicate mesothelioma. Consequently, it is not unusal for a diagnosis of mesothelioma to be overlooked until other, more-probable conditions have been ruled out. 

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• Pleura – membrane surrounding the lungs
• Pericardium – membrane surrounding the heart
• Peritoneum – membrane surrounding the abdominal organs
• Tunica vaginalis – membrane surrounding the testicles

Cancer can arise in any of these membranes and each type is named accordingly:

• Pleural mesothelioma
• Peritoneal mesothelioma
• Pericardial mesothelioma
• Testicular mesothelioma

While most mesotheliomas are malignant and commonly fatal cancers, some tumors can be benign. Two types of benign mesothelioma are:

• Benign fibrous mesothelioma (pleural)
• Benign cystic mesothelioma (peritoneal)

A malignant mesothelioma can also be classified according to the type of cancer cell present. The cell type determines how aggressive the cancer is. Types of malignant mesothelioma cells are:

• Sarcomatous
• Epithelial
• Biphasic

Pleural Mesothelioma

Pleural mesothelioma is sometimes referred to as lung cancer, but technically, it is not a cancer of the lung tissue; it is a cancer of the membrane surrounding the lung – the mesothelium.

Pleural mesothelioma – also often called asbestos cancer – is almost always caused by heavy exposure to asbestos dust in the air. The sharp asbestos fibers infiltrate deep into the lungs and over a period of decades can penetrate the lung’s cell walls. When the fibers work their way into the membrane surrounding the lungs, they can cause a chronic inflammation and eventually stimulate the growth of cancer cells. As these cancer cells reproduce and spread, mesothelioma becomes established.

Of the 2,000 to 3,000 annual cases of mesothelioma, roughly two-thirds are cancer of the pleura. The majority of those diagnosed survive only 12 to 18 months because it is a relatively aggressive cancer and is rarely diagnosed early. According to some recent studies, however, many patients diagnosed early and treated aggressively may survive as long as five years or more.

Peritoneal Mesothelioma

The peritoneum is the membrane surrounding the stomach, liver, pancreas, and intestines. Doctors are not certain how asbestos fibers can become lodged in the peritoneum. Some theorize that swallowing asbestos fibers can result in some sticking in the digestive tract and working their way into the abdominal membrane. Another theory is that asbestos in the lungs may be transported through the lymph system. These potential transport mechanisms can be considered rare because peritoneal mesothelioma is diagnosed in only about 20% to 25% of cases.

Though peritoneal tumors tend to be in more operable locations, the survival rate a short time ago was not that high – typically less than 12 months. But newer treatment strategies combining surgery, radiation and chemotherapy have lengthened median survival rates for this type of mesothelioma to more than five years.

Pericardial Mesothelioma

Asbestos fibers lodging in the pericardium surrounding the heart can also incite cancerous growth. It’s not clearly understood how asbestos fibers migrate from the lungs to the heart, however. One theory is that if asbestos fibers work their way from the lungs into the bloodstream, they may be carried to the heart where they can make their way into the pericardium. The fact that less than 5% to 10% of mesothelioma cases are pericardial mesothelioma indicates how rarely this migration occurs.

Pericardial mesothelioma is also rarely diagnosed early, and as the heart is involved, treatment options are fewer. Most patients with this type of mesothelioma will not survive twelve months.

Testicular Mesothelioma

This type of cancer is so rare only about 100 cases have been documented. Doctors are not certain what causes this mesothelioma of the membrane around the testicles (tunica vaginalis). In some cases they theorize that because the membrane surrounding the testicles is an extension of the peritoneum, primary cancer cells of the peritoneum can spread to the scrotum to create secondary tumors. But when testicular tumors are primary, they have no explanation for how they’re caused.

Because of testicular mesothelioma’s rarity, it can be difficult to generalize about treatments and prognosis. Though surgery to eliminate this type of tumor is easier and much less risky, it can be pointless if a primary tumor remains in the peritoneum. Even when the testicular tumor is primary and surgery is followed with chemotherapy or radiation treatment, residual cancer cells still commonly spread to other organs or lymph nodes often resulting in fatal recurrence within two years.

Benign Fibrous Mesothelioma

This non-cancerous tumor is diagnosed in about 5% of pleural mesothelioma cases.  Its formation is completely unrelated to asbestos exposure. Because it is non-malignant, it is not a rapidly growing or spreading tumor and is not fatal. It is often very localized, well-defined, and easily removed by surgery. While surgery is curative for 90% of patients, 10% will have a recurring tumor up to ten years afterward.

Benign Cystic Mesothelioma

A non-fatal condition, benign cystic mesothelioma is similar to the benign pleural tumor except that it occurs in the peritoneum. At least one case has been reported in the tunica vaginalis, which is an extension of the peritoneum and surrounds the testicles. Nonetheless, benign cystic mesothelioma affects women more often than men. It also tends to occur more often in women of childbearing age.

As with benign fibrous mesothelioma, the peritoneal type is localized and responds well to surgery, though recurrence is still possible. Because it occurs more often in fertile women, studies are being conducted to determine if anti-estrogen drugs such as those used for breast cancer can be effective in preventing recurring tumors.

Sarcomatous Mesothelioma

Sarcomatous mesothelioma is a cancer tumor composed of sarcomatous cells. These irregular shaped cells are very aggressive – meaning they tend to grow and spread quickly. Any of the mesotheliomas – pleural, peritoneal, pericardial, or testicular – can be sarcomatous. 

Sarcomatous mesothelioma occurs in only about 15% of cases. Because it is aggressive and responds poorly to treatment, it leads to a poor average survival rate.

Epithelial Mesothelioma

Mesotheliomas composed of epithelial cells are the most common, representing about two-thirds of all cases. Whether surrounding the lungs, heart, abdomen or testicles, any mesothelioma can be epithelial.

Epithelial cancer cells are not as aggressive as sarcomatous cells, and survival rates tend to be better than for either of the other two cancer cell types.

Biphasic Mesothelioma

Approximately 25% of malignant mesothelioma tumors – regardless of location – contain both epithelial and sarcomatous cell types. One often-quoted study found survival time for biphasic tumors to be worse than either of the other two types.

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