Mesothelioma and non-small cell lung cancer (NSCLC) are two types of cancers. They may have similar symptoms, such as chest pain and difficulty breathing, but there are a few key differences.

Mesothelioma is a rare form of cancer that’s usually due to asbestos exposure. The tumors develop in the tissue surrounding the outside of your internal organs (mesothelium).

Though mesothelioma can form in the tissues surrounding your lungs, it isn’t a type of lung cancer. Mesothelioma can also form in other tissues, such as the lining of your abdomen or heart.

NSCLC is the most common type of lung cancer. While inhaling asbestos can also cause NSCLC, for most people, it’s due to smoking cigarettes.

According to the American Cancer Society, about 3,000 people receive a diagnosis of mesothelioma in the United States each year. On the other hand, they estimate that over 235,000 people will receive a diagnosis of lung cancer in 2022.

Read on to learn more about how NSCLC and mesothelioma are similar and how they differ.


There are two main types of lung cancer: NSCLC and small-cell lung cancer (SCLC). SCLC cells tend to be smaller than NSCLC cells. NSCLC is more common than SCLC, but SCLC tends to grow and spread more quickly than NSCLC.

Asbestos is a risk factor for both SCLC and NSCLC. When you inhale asbestos fibers, the fibers can become trapped in your lung tissue. Over time, this can lead to cancer.

Still, smoking cigarettes is the most common cause of both SCLC and NSCLC. Roughly 80% of all lung cancer deaths result from smoking.

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The most common cause of lung cancer, including NSCLC, is smoking cigarettes or other tobacco products. Other causes and risk factors of NSCLC include exposure to radon, secondhand smoke, air pollution, and asbestos.

On the other hand, the most common cause of mesothelioma is asbestos. About 80% of people who receive a diagnosis of mesothelioma have a history of asbestos exposure.

Asbestos is a naturally occurring mineral fibrous material. Manufacturers often used it in insulation and fire safety products because it’s resistant to fire.

But researchers later learned that when you inhale or swallow asbestos fibers, the fibers can attach to the tissues lining your lungs or digestive tracts and cause cancer. For this reason, the Environmental Protection Agency (EPA) banned the use of asbestos in the United States in 1989.

People in certain jobs are at higher risk of asbestos exposure, especially if they worked in these jobs before the 1970s. These include:

  • insulators
  • construction workers
  • electricians
  • plumbers
  • firefighters

Researchers are still trying to determine other causes of mesothelioma. A fibrous, volcanic mineral known as erionite may also cause mesothelioma. Deposits of erionite are found in the Western United States and North Dakota or in gravel or road development projects.

In some people, doctors don’t know the cause of mesothelioma.

This chart breaks down the currently known risk factors for NSCLC and mesothelioma.

NSCLC causes and risk factorsMesothelioma causes and risk factors
smoking cigarettesexposure to asbestos at work or living with someone who has been exposed to asbestos
other types of tobacco (such as pipes or cigars)exposure to erionite
breathing in secondhand smokeradiation therapy to the chest
exposure to radonfamily history of mesothelioma
exposure to asbestos
particle pollution (air pollution)
exposure to other harmful chemicals, such as uranium, arsenic, cadmium, chromium, and nickel
family history of lung cancer

NSCLC develops in the cells of your lungs. There are three types of NSCLC.

  • Adenocarcinomas: These start in the cells that secrete mucus on your lungs’ outer edges.
  • Squamous cell carcinomas: These start in squamous cells, the flat cells that line the inside of the airways in your lungs.
  • Large cell carcinomas: These can appear in any part of your lung.

NSCLC always starts in your lungs, but the tumors can spread (metastasize) to other areas of your body, including your bones and brain.

Mesothelioma, on the other hand, develops in your mesothelium. That’s the tissue that surrounds the outside of your internal organs.

Mesothelioma most often appears in the tissues lining your lungs (known as the pleura). But it can also develop in other tissues, such as those that line your stomach, testicles if you have them, or heart. When it occurs in the lining of your lungs, it’s called pleural mesothelioma.

Mesothelioma and NSCLC have a similar set of symptoms. Based on symptoms alone, it would be difficult to tell the difference between NSCLC and mesothelioma.

For both diseases, you may not experience any symptoms at all until the cancer is more advanced.

Persistent cough
Shortness of breath
Coughing up blood
Trouble breathing/shortness of breath
Unexplained weight loss
Frequent respiratory infections
Pain in your chest, shoulder, or upper back
Trouble swallowing or feeling like there’s a lump in your throat
Swelling in your face
Swelling and pain in your abdomen
Fluid buildup in your pleura (pleural effusion)

Since lung cancer and mesothelioma share similar symptoms, it’s important to talk with a doctor or healthcare professional about your personal and medical history. This includes your history of smoking and any possible exposure to chemicals or asbestos at work or home. A history of asbestos exposure will be a major sign for doctors to test for mesothelioma.

Once a doctor takes down your history, they’ll likely conduct a physical exam to check for lumps. Other tests include:

  • imaging tests such as a chest X-ray, CT scan, and PET scan of your chest
  • blood tests
  • microscopic examination of sputum (phlegm) to check for cancer cells (sputum cytology)
  • biopsy of the lung or chest wall to obtain a sample of tissue that a lab can analyze

Doctors may be able to tell the difference between the two cancers by the way the tumors develop in your body.

NSCLC tends to develop in individual masses, also known as nodules. Mesothelioma grows as a network of small tumor nodules spread throughout your pleura. They may join to form a sheath around your organ.

Doctors categorize mesothelioma and NSCLC into stages based on:

  • the size and scope of the main tumor
  • if the tumor has spread to nearby lymph nodes
  • if the tumors have spread to other parts of your body, such as your brain or bones (metastasis)

In general, there are four stages for both diseases. The lower the stage number, the less your cancer has spread.

Keep in mind that there are many cancer staging systems, and doctors will also break down each stage into more specific sub-stages depending on the size of your tumor and how it’s spreading.

0 (carcinoma in situ)The tumor is only in the top layer of cells lining the air passages. It hasn’t spread deeper into other lung tissues, the lymph nodes, or other parts of the body.You have a single layer of atypical mesothelial cells without invasive lesions.
1 (localized)The cancer has minimally invaded the deeper lung tissues but is still very small. It hasn’t spread to the lymph nodes or other parts of your body.The cancer is in the cells lining your chest or diaphragm. It may have grown into nearby structures, but doctors can likely still remove it with surgery. It hasn’t spread to the lymph nodes or other parts of your body.
2 (regional)The cancer is larger than in stage 1 and may have spread to lymph nodes within your lung.The cancer is in the cells lining your chest wall, diaphragm, or lung. The cancer has also spread to nearby lymph nodes on the same side of your body as the main tumor.
3 (locally advanced or regional)The cancer has spread into the deeper tissues of your lung, including the chest wall, and to lymph nodes within or outside your lung. But it hasn’t spread to distant parts of your body.The cancer has spread into nearby structures and lymph nodes but hasn’t spread to distant parts of your body.
4 (distant)The cancer may have spread to your other lung, the fluid around your heart, and distant parts of your body, such as distant lymph nodes or other organs like your brain.The cancer has spread to distant organs, such as your bones or the lining of your abdomen.

Both mesothelioma and lung cancer can be treated with surgery if diagnosed in the early stages.

For mesothelioma, surgery may only remove the lining around your lungs (pleurectomy) or the membrane that lines the cavity of your abdomen (peritonectomy).

For lung cancer, surgery aims to remove the tumor itself or a lobe or section of your lung. A surgeon may also decide to remove one entire lung.

If the cancer is more advanced, doctors may treat it with chemotherapy, radiation, targeted therapy, immunotherapy, or a combination of these treatments.

Immunotherapy works by stimulating your immune system to attack and kill cancer cells. The Food and Drug Administration (FDA) has approved several immunotherapy drugs to treat advanced NSCLC and mesothelioma. These include pembrolizumab (Keytruda) and nivolumab in combination with ipilimumab (Opdivo plus Yervoy).

The type of surgery or medication a doctor uses will depend on which disease you have, as well as the cancer stage, tumor size, and your overall health.

People with mesothelioma or lung cancer often experience fluid buildup in the lining of their lungs (pleural effusion). A doctor may recommend surgery to remove your fluid buildup (thoracentesis).

The outlook for people with mesothelioma and people with NSCLC depends on several factors, including how early doctors find their cancer. Researchers typically measure outlook in terms of 5-year survival rates. This is the percentage of people still alive 5 years after they receive a diagnosis of mesothelioma of NSCLC.

The outlook is generally worse for people with mesothelioma compared with those with NSCLC in the earlier stages. The outlook is relatively the same for people with mesothelioma and those with NSCLC once cancer spreads to other parts of their body.

Keep in mind that the 5-year survival rate is based on past data and doesn’t consider recent advances in treatment.

According to the American Cancer Society, the 5-year relative survival rates for people who received a diagnosis of NSCLC and people who received a diagnosis of mesothelioma between 2011 and 2017, broken down by stage, are:

StageNSCLC, 5-year relative survival rateMesothelioma, 5-year relative survival rate
All stages combined26%12%

Mesothelioma and NSCLC are both types of cancer that asbestos can cause, but they’re very different diseases.

Smoking usually causes NSCLC, which develops in the cells of your lung. Mesothelioma is usually due to asbestos exposure and can develop in the tissues lining your lungs, heart, or abdomen. Mesothelioma is much less common than NSCLC.

Still, doctors may misdiagnose mesothelioma as lung cancer. It’s important to tell a doctor about your medical history, including your history of smoking and possible exposure to asbestos. Since asbestos can cause both cancers and they have similar symptoms, it may be a good idea to get a second opinion to ensure the diagnosis you receive is accurate.