If you or someone you love has been diagnosed with mesothelioma, you may find yourself with questions. One of the most common: What is the relationship between mesothelioma and lung cancer?

These two conditions are related but not identical. Although they share some symptoms, diagnostic tests, and treatments, they appear in different locations and have varying risk factors. It’s important to understand the differences between these two conditions so you can seek out the best treatment for yourself or your loved one.

What Is Mesothelioma?

Mesothelioma is a form of cancer that occurs in the lining, or mesothelium, of the abdomen and/or chest cavity. This lining protects and covers all the abdominal organs. The cancer can occur anywhere in the mesothelium but is most common in the lining around the lungs, called the pleura. This form of the disease, known as pleural mesothelioma, accounts for 85 percent of mesothelioma cases. It can also occur in the lining of the abdominal space (peritoneum) or the lining around the heart (pericardium).

Is Mesothelioma a Type of Lung Cancer?

Experts don’t always agree on whether mesothelioma is a form of lung cancer. What is commonly accepted is that both are types of cancer that affect the lungs.

Some cancer research experts say that pleural mesothelioma is not technically lung cancer but a lung disease related to lung cancer. This is because mesothelioma occurs in the space around the lungs and not in the lungs themselves.

Other experts consider mesothelioma a type of lung cancer because there is no better way to categorize it. The disease has some symptoms similar to those of lung cancer, and lung cancer oncologists are often the doctors who treat it.

Many resources on pleural mesothelioma are vague or conflicting as to whether it is a type of lung cancer. Ultimately, although experts may have contrasting views on the classification of mesothelioma, the important thing is to understand the specifics of the disease to get the best possible treatment for yourself or your loved one.

How Are Mesothelioma and Lung Cancer Different?

There are several key differences between mesothelioma and most lung cancers.

Location: Mesothelioma vs. Lung Cancer

As explained above, mesothelioma and lung cancer affect different structures in the body. In pleural mesothelioma, the cancer is located in the tissue that surrounds and protects the lungs (the pleural tissue). Mesothelioma can also affect mesothelial tissue wherever it is located, including the heart, stomach, and testicles.

Lung cancer develops in the lung tissue. Although advanced lung cancer can spread to other areas of the body, it begins in the lungs and, when analyzed, is identifiable as a lung cancer tumor. There are several types of lung cancer, including small cell and non-small cell, but they all begin inside or on the lung itself.

Causes of Mesothelioma

The biggest differences between mesothelioma and lung cancer involve their causes and risk factors.

The majority of malignant (cancerous) mesothelioma cases result from exposure to asbestos, a material that was once used for insulation and fireproofing and is a known carcinogen (cancer-causing agent). Asbestos is fibrous, and fibers that are breathed in can be difficult to clear from the body. Over time, uncleared fibers can cause mesothelioma.

According to NORD, an organization dedicated to people with rare diseases, 70 percent to 80 percent of individuals diagnosed with mesothelioma report significant exposure to asbestos dust and products. The exposure can occur from 30 to 50 years before symptoms appear. This gives asbestos a long latency period in the body before the harm it causes can be identified. There are many other asbestos-related diseases and lung cancers, such as asbestosis, but mesothelioma is one of the best known.

Most exposure to asbestos happens on the job. People involved in occupations such as construction and roofing, as well as those doing some mechanic or production work, may have been exposed to the material.

Asbestos has been outlawed, and its use diminished drastically after 1989, according to NORD. However, people exposed to asbestos before its ban can still develop mesothelioma. Those with a history of asbestos exposure may choose to get tested for the condition regularly.

Causes of Lung Cancer

On the other hand, smoking is the most significant cause of lung cancer but is not widely discussed as a cause of mesothelioma. In fact, many of those diagnosed with mesothelioma are nonsmokers.

Note that both mesothelioma and lung cancers can have other causes. Genetics seem to play a role in putting people at increased risk of developing both lung cancer and mesothelioma, as does exposure to several other carcinogenic substances such as arsenic, nickel, or radon gas.

How Are Mesothelioma and Lung Cancer Similar?

Mesothelioma and lung cancers share some significant similarities.

Symptoms

The most notable similarity between mesothelioma and lung cancer is the overlap in symptoms.

Mesothelioma in the lungs can cause people to experience:

• Significant to extreme tiredness
• A cough that is always present and does not improve over time
• Shortness of breath that is severe enough to interfere with daily activities
• Lost appetite and unexplained weight loss
• Chest pain, often in disperse or difficult-to-pinpoint locations
• Fever and sweating, especially at night
• Significantly swollen fingertips

The symptoms of lung cancer have some significant overlap with those of mesothelioma, including:

• Shortness of breath of varying severity, from having an insignificant impact to making it difficult to do everyday tasks
• Chest pain
• A cough — usually a new cough, although it may begin with an illness — that doesn’t resolve
• Unintentional weight loss

Lung cancer may also cause other symptoms that are not normally seen in mesothelioma, including:

• Hoarseness without another explanation
• Persistent headache
• Coughing up blood (hemoptysis), even if in minuscule amounts
• Pain in the bones

Diagnosis

The diagnostic procedure for both lung cancer and mesothelioma relies on imaging tests, including X-rays and CT scans. These tests allow oncology experts and health care professionals to detect any tumors, nodules, lesions, or other indications of cancer in the lungs and their lining.

Diagnosis of lung cancer and mesothelioma will also likely include some sort of fluid and/or tissue sample (biopsy). This may involve collecting sputum (a mixture of mucus and saliva) or other fluid coughed up from the lungs, removing fluid from around the lungs, or taking samples of any tumors or other spots visible on the lungs. All these tests involve examining the samples for cancer cells.

Treatments

Some of the treatment options for mesothelioma and lung cancer are identical or similar. Both conditions are usually treated with a combination of surgery (to remove cancerous tissue), chemotherapy, and radiation therapy. However, the application of these therapies may differ, and the chemotherapy drugs used may be based on the specific characteristics of the cancer that you have.

Find Your Team

At MyLungCancerTeam, you can find support for your journey with mesothelioma or lung cancer. Feel free to ask questions about mesothelioma, share your experience with the condition, or join in on current conversations. Before you know it, you’ll have the support you’ve been looking for on your journey with mesothelioma.

Are you living with mesothelioma? Have you noticed any differences between your experiences and those of people living with lung cancer? Share your story in the comments below, or start a conversation by posting on your Activities page.