Pleural mesothelioma is the most common form of cancer affecting the mesothelium, the protective membrane around your lungs, heart, and abdomen. While rare, this cancer can progress quickly, so it’s important to be aware of the symptoms and risk factors.

In this article, we explore the symptoms and risk factors for this cancer, as well as how it’s diagnosed, staged, and treated.

Pleural mesothelioma is a rare type of lung cancer primarily caused by workplace asbestos exposure. It’s the most common subtype of mesothelioma, and it affects mesothelial cells within the “pleura” or lining of your lungs, creating malignant tumors.

While there are approximately under 3,000 new cases of mesothelioma reported annually in the United States, overall numbers of new patients have been declining over the last 2 decades because of decreased asbestos exposure.

But despite the declining number of new cases, pleural mesothelioma is an aggressive cancer that warrants prompt diagnosis and treatment. Read on to learn the common risk factors and symptoms associated with this type of mesothelioma so you can discuss critical next steps with your doctor.

The symptoms of pleural mesothelioma may not show up for 30 to 50 years after you’ve been exposed to asbestos.

In its earliest stages, pleural mesothelioma may not cause any symptoms. But once it’s advanced, you may experience the following:

You should call your doctor right away if you’re experiencing the above symptoms, especially if you have a known asbestos exposure. This is an aggressive cancer that requires prompt diagnosis and treatment. Unexplained but frequent pneumonia also warrants a doctor’s visit.

While the exact cause is unknown, previous asbestos exposure — especially in the workplace — remains the most common risk factor for pleural mesothelioma.

In fact, according to the American Lung Association, approximately 8 out of every 10 people diagnosed with mesothelioma had a history of asbestos exposure.

When you inhale asbestos fibers, they can eventually make their way into the pleura of your lungs. Over time, irritation and inflammation can occur and possibly lead to the development of cancerous cells.

What is absestos?

Asbestos is a material used to make insulation in buildings due to its fire and heat-resistant capabilities. While asbestos is now banned, it was widely used in homes and other buildings constructed before the 1970s.

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You may be at risk of asbestos exposure if you live or work in a building that has asbestos. Certain occupations that take place in older buildings or ones that dealt with asbestos prior to the 1970s may also increase your risk of mesothelioma.

These include:

  • insulators
  • construction workers
  • electricians
  • miners
  • millers
  • pipefitters
  • plumbers
  • firefighters

Another key risk factor is the length and amount of exposure to asbestos. If you had long-term exposure to a large amount of the material, then you may have a higher risk of developing pleural mesothelioma than someone who had little exposure.

Other risk factors for pleural mesothelioma include:

  • inherited genetic mutations (occurs in about 1 percent of people diagnosed with mesothelioma)
  • advanced age, with 72 years being the average age of onset
  • receiving radiation therapy as a child

Based on your symptoms and history of possible asbestos exposure, your doctor will first order imaging tests of your lungs, like an X-ray or CT scan. Such tests may be able to identify:

  • pleural thickening in your lungs
  • calcium deposits called pleural plaques
  • fluid accumulation that may indicate pleural effusion

If your doctor suspects pleural mesothelioma, they may conduct further imaging tests along with a biopsy to obtain a tissue sample. The biopsy is sent to a lab for evaluation to identify the type of cancer. You might also need biopsies in other areas of the body if the cancer has spread.

The cancer is also classified based on the appearance of the cells:

  • epithelioid cancer cells, which make up more than 50 percent of all mesotheliomas and have the best outlook
  • fibrous (sarcomatoid) cells
  • combination of epithelioid and sarcomatoid cells (biphasic/mixed)

Overall, here’s how pleural mesothelioma is staged:

Stage NumberDescription
IAThe cancer is localized in the pleura, but may or may not have spread to the diaphragm. It has not spread to the lymph nodes.
IBPleural mesothelioma has spread to the diaphragm, as well as the chest wall. The lymph nodes are not affected.
IIThe cancer has become more regional, spreading to the diaphragm, chest wall, and lungs. It may also spread to lymph nodes on one side of your body.
IIIAWhile mesothelioma may start spreading to fatty tissues and deeper chest wall layers, it may still be surgically removed at this stage.
IIIBSurgery is no longer a viable treatment option at this stage because the cancer has spread to other organs, blood vessels, and deeper tissues. Your doctor will focus on other treatments instead. But pleural mesothelioma is still considered more regional at this stage, as it hasn’t spread to other distant parts of the body.
IVThe cancer may spread to the lymph nodes, distant organs like the liver, the bones, or the abdomen.

Treatment for pleural mesothelioma may consist of one or more of the following options:

  • chemotherapy to shrink cancer cells and prevent further growth
  • targeted therapies that directly fight cancer cells
  • immunotherapy drugs that utilize your immune system to attack cancer cells
  • surgery to remove the pleura (pleurectomy) or a larger part of the lung
  • surgery to remove fluid buildup (thoracentesis) for effusions

Effusions affect about 66 percent of all people with mesothelioma. If you have pleural effusion, thoracentesis (a procedure performed to remove excess fluid or air from your pleural space) can help improve quality of life, but it doesn’t remove actual cancer cells.

Thoracentesis may also be repeated to help address related symptoms, like chest pain and shortness of breath. During the procedure, your doctor will remove the fluid via fine-needle aspiration and an ultrasound.

According to the American Cancer Society, the overall 5-year survival rates for pleural mesothelioma based on data collected between 2010 and 2016 were as follows:

Location and stage at diagnosisPercent living after 5 years
localized (stages IA and IB)18 percent
regional (stages II, IIIA, and IIIB)12 percent
distant, has spread to other areas of the body (stage IV)7 percent

Many factors aside from the cancer’s location can impact your overall prognosis. This includes your age, overall health, and advances in treatment. The stage of your cancer at the time of diagnosis also makes a difference.

It’s best to talk with your doctor about your individual case and outlook. While pleural mesothelioma is historically aggressive, current data doesn’t reflect improvement in treatments for this cancer.

Pleural mesothelioma is a type of cancer that starts in the lining of your lungs. While rare, this cancer progresses quickly and may be at an advanced stage before symptoms begin. Asbestos exposure remains the greatest risk factor for developing mesothelioma.

Due to the aggressive nature of this cancer, it’s important to see your doctor for diagnosis of any possible symptoms of pleural mesothelioma. This is especially the case if you’ve previously worked in industries where asbestos exposure was rampant, such as construction or mining.

Treatments for pleural mesothelioma continue to advance, and surgery may even be an option at the earlier stages of this cancer. Talk with your doctor about all of your options so you can make the best decisions for your outlook and quality of life.