Mesothelioma is a rare but aggressive cancer that develops in the thin layer of tissue covering many internal organs, most commonly the lungs. This disease is strongly linked to asbestos exposure and typically appears decades after contact with these harmful fibers, making early detection challenging and treatment complex.

How Common is Mesothelioma Around the World

Mesothelioma remains a relatively uncommon cancer, but its impact on affected communities can be significant. In the United States, approximately 3,300 new cases are diagnosed each year, which is notably fewer than other cancers like lung cancer, which sees nearly 200,000 new cases annually^[4]. This rarity means many doctors never encounter the disease during their careers, which can sometimes lead to delays in proper diagnosis.

The disease shows clear patterns in who it affects. Men are three times more likely to be diagnosed with mesothelioma than women^[4]. This gender difference relates directly to historical workplace exposures, as men more commonly worked in industries where asbestos was present. The disease typically appears in people during their fifth and sixth decades of life, meaning most patients are diagnosed in their 40s through 60s^[4].

In the United States, cases have been declining since 2000 due to improved workplace safety regulations and greater awareness of asbestos dangers^[4]. However, certain areas still see higher numbers of cases, particularly regions near shipping industries or other asbestos-heavy workplaces. For example, Louisiana reported 57 cases statewide in 2009, with 12 cases concentrated in the greater New Orleans area, which includes Jefferson, Orleans, and St. Bernard parishes^[4].

Globally, more than 125 million people have been exposed to asbestos at work as of 2013^[3]. While the incidence is decreasing in the United States, some parts of the world still experience rising rates of mesothelioma. This reflects differences in when various countries began regulating asbestos use and removing it from buildings and products. During 2015, approximately 60,800 people worldwide were affected by mesothelioma, and the disease claimed 32,400 lives that same year^[3].

More than half of all mesothelioma patients present with stage III or stage IV disease at diagnosis^[4]. These stages represent advanced cancer, where tumors have spread beyond their original location. This late-stage presentation at diagnosis is one reason why mesothelioma remains such a serious health challenge.

What Causes Mesothelioma

The overwhelming cause of mesothelioma is exposure to asbestos. More than 80% of mesothelioma cases result from contact with this mineral^[3]. In fact, studies suggest that up to 70% of documented cases involve confirmed asbestos exposure, though the actual percentage may be higher since not all exposure histories are fully documented^[4].

Asbestos is a group of naturally occurring minerals found in rocks and soil. These minerals form long, thin, very strong fibers that resist heat, fire, and chemical breakdown^[2]. Because of these properties, asbestos was widely used throughout the 20th century in many consumer products, automobile parts, and building materials. Industries valued asbestos for insulation, fireproofing, and strengthening various materials.

The problem occurs when materials containing asbestos are disturbed. This releases tiny asbestos fibers into the air—fibers so small they cannot be seen with the naked eye^[2]. When people breathe in or swallow these fibers, the particles settle in the lungs or abdomen. The human body cannot break down asbestos fibers. They are simply too tough and resistant. Over many years, these trapped fibers cause scarring and inflammation in tissues. They also trigger cellular changes that eventually lead to cancer development^[17].

Asbestos was heavily used in the United States until scientists learned about its health dangers in the 1960s and 1970s. Although asbestos is no longer mined in the United States, it is still imported from other countries to manufacture some products^[2]. Additionally, asbestos remains present in older homes and buildings where it was installed decades ago.

While asbestos exposure is the primary cause, researchers have identified other potential risk factors. Some studies suggest that infection with simian virus 40 (SV40), a virus that contaminated some polio vaccines in the past, may play a role^[3]. Genetic factors may also influence who develops mesothelioma after asbestos exposure, though this connection is not fully understood^[3]. In rare cases, exposure to other minerals like erionite, which is naturally found in certain geographical areas, has been linked to mesothelioma development^[3].

Who is at Risk for Developing Mesothelioma

Certain groups of people face higher risks of developing mesothelioma based on their work history, living situation, or personal circumstances. Understanding these risk factors helps identify who should be especially watchful for symptoms.

Workers who directly handled asbestos or asbestos-containing materials face the greatest risk. This includes people who mined asbestos, manufactured products from asbestos, or worked with asbestos products in construction or other trades^[3]. Factory workers, shipbuilders, military veterans, and insulation professionals are among those with elevated risk^[9]. The greater and longer the exposure, the higher the risk becomes^[3].

Military service members, particularly those in the Navy, face significant mesothelioma risk. Ships built before the 1980s often contained extensive asbestos insulation in engine rooms, sleeping quarters, and other areas. Service members who worked in shipyards or on vessels were exposed to asbestos fibers when materials deteriorated or during maintenance and repair work.

Family members of asbestos workers also face risk through what is called secondary or paraoccupational exposure. Workers can carry asbestos fibers home on their clothing, shoes, or skin. Family members who handle contaminated work clothes or live in the same household can inhale these fibers^[3][8]. Washing the clothing of someone who worked with asbestos increases this risk^[3].

People who live or work in buildings where asbestos-containing materials have been disturbed face potential exposure^[2]. This might occur during renovation, demolition, or when materials naturally deteriorate over time. Living in areas with natural asbestos deposits, or near asbestos mines or factories, also elevates risk^[2].

Age and gender play roles in mesothelioma risk. Men older than 65 face higher risk^[9], partly because they are more likely to have worked in asbestos-exposed occupations decades earlier. The long latency period means older individuals who were exposed in their youth are now reaching the age when mesothelioma typically appears.

People who received high doses of radiation to the chest or abdomen for other medical conditions may have increased mesothelioma risk^[9]. Smoking does not directly cause mesothelioma, but it significantly compounds the cancer risk for people exposed to asbestos. Asbestos workers who smoke have a 60-fold increased risk of developing non-small cell lung cancer compared to non-smokers without asbestos exposure^[4].

It is important to note that not everyone exposed to asbestos will develop mesothelioma or other cancers^[2]. Many factors influence whether disease develops, including the intensity and duration of exposure, the type of asbestos fibers involved, and individual susceptibility factors that scientists do not yet fully understand.

Signs and Symptoms of Mesothelioma

Mesothelioma symptoms develop gradually and often go unnoticed for a long time. The disease typically starts causing problems many years after asbestos exposure, and early signs can be subtle enough that people may dismiss them or attribute them to other, less serious conditions.

The symptoms a person experiences depend largely on where the cancer develops in the body. The most common form is pleural mesothelioma, which affects the tissue surrounding the lungs. People with pleural mesothelioma may experience chest pain, particularly under the rib cage^[1][2]. This pain can be persistent and bothersome. They often develop shortness of breath, which worsens over time as fluid accumulates around the lungs or as tumors grow^[1].

A persistent cough is another common symptom of pleural mesothelioma. This cough is typically dry and does not produce mucus^[9]. Some people notice lumps under the skin on their chest as tumors develop^[1][2]. Difficulty swallowing may occur if tumors press against the esophagus^[9].

When mesothelioma develops in the abdomen, the condition is called peritoneal mesothelioma. This form causes different symptoms. People may notice their abdomen becoming swollen or distended^[1][2]. Abdominal pain is common and can range from mild discomfort to severe pain. Nausea may occur, making it difficult to eat normally^[1]. Some people experience changes in bowel habits, including constipation^[7].

Regardless of where mesothelioma develops, certain symptoms affect the body overall. Unexplained weight loss is very common^[1][2]. People lose weight without trying or without changes to their diet. Fatigue, or feeling extremely tired, affects most mesothelioma patients^[1][2]. This tiredness does not improve with rest and can make daily activities challenging. Some people develop night sweats or experience fever^[7].

In rare cases, mesothelioma affects the tissue around the heart, called pericardial mesothelioma. This type causes difficulty breathing and chest pains^[1]. It may also cause irregular heartbeat or heart murmurs^[9]. Even rarer is mesothelioma of the tissue around the testicles, known as mesothelioma of tunica vaginalis. This usually first appears as swelling or a mass on a testicle^[1].

Because these symptoms develop slowly and can resemble other, more common illnesses, many people do not seek medical attention right away. Symptoms like coughing, fatigue, and breathing difficulties might be mistaken for normal signs of aging, a cold, or other respiratory conditions. This delay in seeking care is one reason why mesothelioma is often not diagnosed until it has reached advanced stages.

Anyone experiencing these symptoms, particularly if they have a history of asbestos exposure, should consult a doctor. While these symptoms may be caused by conditions other than cancer, only a medical professional can determine the true cause through proper examination and testing^[2].

How to Reduce Your Risk of Mesothelioma

The most effective way to prevent mesothelioma is to reduce or eliminate exposure to asbestos. Since asbestos causes the vast majority of cases, protecting yourself and others from these fibers is the key prevention strategy^[3].

For people working in industries where asbestos might be present, following proper safety procedures is essential. Workers should use appropriate protective equipment, including respirators and protective clothing. Employers in industries with potential asbestos exposure should provide training about safe handling procedures and ensure proper ventilation in work areas. Following workplace safety regulations helps minimize the amount of asbestos fibers workers might breathe in or swallow.

If you live or work in an older building, be aware that asbestos-containing materials might be present. Buildings constructed before the 1980s commonly used asbestos in insulation, floor tiles, ceiling materials, and other products. Intact asbestos materials are generally safe^[17]. The danger arises when these materials are disturbed during renovation, demolition, or as they deteriorate with age. If you plan renovations in an older building, have professionals inspect for asbestos before starting work. Trained specialists can safely remove or contain asbestos materials.

Never attempt to remove asbestos materials yourself. Disturbing asbestos releases fibers into the air, creating serious health risks. Professional asbestos abatement contractors have specialized training and equipment to handle removal safely. They follow strict protocols to prevent fiber release and protect both workers and building occupants.

For family members of people who work with asbestos, taking precautions against secondary exposure is important. Workers should shower and change clothes before leaving work, if possible. Work clothes should be laundered separately from family laundry, ideally by the employer’s laundry service. These simple steps can dramatically reduce the asbestos fibers brought into the home.

If you have a history of asbestos exposure, talk to your doctor about your risk. Your doctor might recommend regular checkups or specific tests to monitor for asbestos-related diseases^[2]. While no screening test can prevent mesothelioma, early detection of any changes can help ensure prompt treatment if problems develop.

Currently, there are no vaccines or medications that can prevent mesothelioma. No dietary supplements or lifestyle changes have been proven to reduce mesothelioma risk in people already exposed to asbestos. The only proven prevention strategy is avoiding asbestos exposure in the first place.

How Mesothelioma Affects the Body

Understanding what happens inside the body when mesothelioma develops helps explain why the disease causes particular symptoms and why treatment can be challenging. The disease process involves multiple changes to normal body functions at the physical, mechanical, and biochemical levels.

Mesothelioma starts in the mesothelium, a thin layer of tissue that covers and protects internal organs^[1]. This tissue normally produces a small amount of lubricating fluid that allows organs to move smoothly against each other. For example, the mesothelium around the lungs, called the pleura, allows the lungs to expand and contract smoothly during breathing.

When asbestos fibers become trapped in mesothelial tissue, they trigger chronic inflammation and scarring over many years. The fibers cause direct physical damage to cells and trigger the body’s immune response. This ongoing inflammation eventually causes changes in how mesothelial cells grow and divide. Instead of growing in an orderly, controlled way, cells begin multiplying abnormally. These abnormal cells accumulate and form tumors.

As mesothelioma tumors grow in the pleura around the lungs, they often cause fluid to accumulate in the space between the lung and chest wall. This condition, called pleural effusion, reduces the space available for the lung to expand. As fluid builds up, breathing becomes increasingly difficult. People feel short of breath even with minimal physical activity. The growing tumors also press against the lung, further limiting its ability to inflate fully.

The tumors themselves can invade nearby structures. In pleural mesothelioma, cancer cells may spread from the lung lining to the lung tissue itself, the diaphragm (the muscle that controls breathing), or the chest wall. This invasion causes pain, particularly when breathing deeply or coughing, because movement stretches the affected tissues.

In peritoneal mesothelioma, tumors grow in the membrane lining the abdominal cavity. These tumors can cause fluid buildup in the abdomen, called ascites. The accumulating fluid and growing tumors make the abdomen swell visibly. Tumors may press against the intestines, causing constipation or changes in bowel function. They can also affect the stomach, leading to nausea and loss of appetite.

As mesothelioma progresses, cancer cells can spread beyond their original location. They may travel through the lymphatic system, which is a network of vessels and organs that help fight infection. Cancer cells that reach lymph nodes can then spread to distant organs, including the liver, bones, or brain. This spreading process, called metastasis, represents advanced disease and makes treatment more difficult.

The body’s immune system tries to fight the cancer, but mesothelioma cells develop ways to evade immune detection and destruction. The ongoing battle between cancer and the immune system contributes to symptoms like fatigue, fever, and night sweats. The body expends enormous energy trying to combat the disease, leaving people feeling exhausted.

Cancer cells also alter normal metabolism. They consume nutrients that the body would otherwise use to maintain healthy tissue. This metabolic disruption, combined with reduced appetite from tumor effects, leads to unintended weight loss. The body essentially begins breaking down its own muscle and fat stores to provide energy.

Understanding these disease processes helps explain why mesothelioma is so serious. The cancer affects vital organs and systems, disrupting breathing, digestion, and overall body function. The tendency for mesothelioma to spread to multiple areas makes it difficult to remove completely with surgery or target effectively with other treatments.