Mesothelioma is a type of cancer that affects the lining of organs, including the lungs. Mesothelioma and lung cancer can cause some similar symptoms, such as chest pain and difficulty breathing.

Cancer is a broad term to describe a group of diseases that involve abnormal cell growth. They can start almost anywhere in the body, and each type of cancer behaves differently.

Lung cancer is a common and serious type of cancer. The American Cancer Society estimates that doctors will diagnose over 230,000 new cases in the United States in 2022. Doctors most often diagnose lung cancer in older people with a history of smoking.

Mesothelioma is another form of cancer. However, it is relatively rare compared with lung cancer, with only around 3,000 new diagnoses occurring annually in the U.S. Mesothelioma develops in the lining that covers the outer surface of some organs such as the lungs, heart, and abdomen. Doctors usually link it to asbestos exposure.

This article compares mesothelioma and lung cancer treatments, causes, and diagnosis methods.

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In some cases, mesothelioma can affect the lungs. Mesothelioma or malignant mesothelioma is a rare type of cancer that develops in the cells that make up the mesothelium. The mesothelium is a thin membrane that covers and protects some internal organs.

Mesothelioma typically develops in the pleura, the tissue that lines the lungs and chest cavity. However, it may also affect the lining of the abdomen, heart, and testicles.

According to the National Cancer Institute (NCI), the most common cause of mesothelioma is asbestos exposure, and different types of asbestos may pose different levels of risk. It can take 10–40 years or more from the time of exposure for mesothelioma symptoms to appear, as the condition develops slowly.

Asbestos exposure can also increase the risk of asbestosis, an inflammatory lung condition that may or may not cause significant lung function impairment. However, the NCI states that everyone experiences asbestos exposure during their life, and most people do not become ill from it. Those who do have generally experienced regular exposure, for example, at work.

There are some similarities between the symptoms of mesothelioma and lung cancer.

The most common symptoms of pleural mesothelioma are:

Around 90% of individuals with pleural mesothelioma have pleural effusion, a buildup of fluid in the space between the lungs and the chest cavity. People with the condition usually see a doctor because of chest pain and shortness of breath.

Conversely, an individual with lung cancer may not experience any symptoms until the cancer spreads. If someone has symptoms, they may include:

Doctors diagnose pleural mesothelioma using the following evaluations:

  • Chest X-ray: This simple imaging study allows doctors to look for signs of asbestos exposure, including calcium deposits and thickened areas in the lining of the lungs.
  • CT scan with intravenous contrast: This is a specialized X-ray that shows cross-sectional images of the body. Doctors use a contrast dye injected into a vein to highlight the tissues and structures, allowing them to see more detail.
  • Thoracentesis: If doctors identify a buildup of fluid between the lungs and the chest wall, they will drain some fluid with a needle to exclude potential causes.
  • Biopsy: A doctor obtains a small tissue sample from the chest wall while the individual is under anesthetic. They then send the sample to the laboratory to look for mesothelioma.
  • PET scan: If the individual has mesothelioma, a doctor may recommend a PET scan to see if the cancer has spread.

Doctors use a similar approach of imaging and biopsies to diagnose lung cancer. They may also recommend an MRI scan to provide detailed images using radio waves and powerful magnets. MRI scans can help doctors look for lung cancer that has spread to the brain or spinal cord.

If the doctor finds a suspicious mass on the chest images, they may take a biopsy or tissue sample from the area to send to the lab for analysis.

Mesothelioma is an aggressive form of cancer with no cure. However, if doctors catch it early enough, surgery to remove the affected areas is an option. Even if surgery cannot completely treat the cancer, it can reduce fluid buildups that cause breathing difficulties.

Doctors may also recommend chemotherapy to reduce uncomfortable symptoms. Chemotherapy is a strong form of medication that can shrink and slow the growth of cancer cells. Other options include immunotherapy to support the immune system in fighting cancer cells.

If an individual has lung cancer, doctors will decide on the best treatment depending on the type of lung cancer and its spread. Options include:

  • surgery to remove cancerous masses or portions of the lungs
  • chemotherapy to shrink and kill cancer cells
  • radiation therapy using high energy rays to destroy cancer cells
  • targeted therapy to block the growth and spread of cancer

In cases of non-small cell lung cancer (NSCLC), doctors may recommend a combination of the above treatments. Radiation therapy and chemotherapy are the standard options for small cell lung cancer (SCLC).

Doctors typically diagnose malignant mesothelioma when an individual has symptoms and the condition is advanced. It is an aggressive form of cancer and is usually life threatening. Most individuals with pleural mesothelioma have a median survival of fewer than 14 months.

Although mesothelioma is a serious condition, palliative care can help control an individual’s symptoms by controlling pain and making life more comfortable.

The outlook for a person with lung cancer will depend on the type of cancer, its stage, and the person’s general health.

According to the NCI, the overall 5-year survival rate for lung cancer is around 22%. This means that around 1 in 5 people with lung cancer live for five years or more following their diagnosis. The 5-year survival rates for NSCLC and SCLC are 25% and 7%, respectively.

Lung cancer and mesothelioma are both cancers that can affect the lungs. However, mesothelioma describes a condition that affects the cells that make up the mesothelium. As the mesothelium lines the lungs, abdomen, heart, and testicles, it can also develop in any of these places.

Mesothelioma is rare and typically occurs due to asbestos exposure. In contrast, lung cancer is a relatively common form of cancer and typically affects people with a history of smoking.

Symptoms of both conditions may include difficulty breathing, coughing, and chest pain. Doctors may use a similar approach to diagnose both conditions.