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Dr. Jacques Fontaine: Dr. Jacques Fontaine - What are the differences between mesothelioma and lung cancer?
What’s the Difference Between Mesothelioma and Lung Cancer?
Mesothelioma and lung cancer develop in very different ways. Pleural mesothelioma starts as nodules, merges and grows as a sheet over time that coats the lining around the lung. Lung cancer grows as discrete tumor masses, individual lumps like marbles, that grow outward.
Because the most common type of mesothelioma develops in the lining of the lung, it’s sometimes mistakenly referred to as “mesothelioma lung cancer.” But mesothelioma isn’t a type of lung cancer.
Doctors diagnose about 229,410 Americans with lung cancer each year, compared with roughly 3,000 mesothelioma cases. As thoracic surgeon Dr. Jacques Fontaine of Moffitt Cancer Center tells us, “For every mesothelioma case we diagnose, we diagnose 95 lung cancers.”
| Mesothelioma | Lung Cancer | |
|---|---|---|
| Where it forms | Lining around the lungs, abdomen, heart and testes | Inside lung tissue |
| U.S. cases per year | About 3,000 | About 229,410 (ACS, 2026) |
| Primary cause | Asbestos exposure | Smoking causes about 80% of cases; asbestos causes about 4% |
| Latency period | 20 to 60 years after asbestos exposure | 15 or more years after asbestos exposure |
| 5-year survival rate | 12% | 28% |
| Cell types | Epithelioid, sarcomatoid and biphasic | Non-small cell and small cell |
| Common symptoms | Chest pain, shortness of breath and pleural effusion | Persistent cough, chest pain and blood in sputum |
How Smoking and Asbestos Together Raise Lung Cancer Risk
Asbestos exposure causes nearly all mesothelioma cases and 4% of lung cancer cases, whereas smoking only causes lung cancer. It doesn’t cause mesothelioma. When smoking is combined with asbestos exposure, the risk increases dramatically. A person who smokes and has worked with asbestos faces a much higher lung cancer risk than someone with either exposure alone.
Asbestos fibers get stuck in tissues in the body, causing chronic inflammation and scarring. Smoking introduces dozens of cancer-causing chemicals. Quitting smoking after asbestos exposure substantially lowers the risk of lung cancer, but it doesn’t eliminate it entirely.
Similarities Between Mesothelioma and Lung Cancer
Both lung cancer and mesothelioma are asbestos-related cancers that often take years to develop and cause chest pain and breathing trouble. Doctors also diagnose both with imaging scans and a biopsy confirms the diagnosis. These similarities may help explain why people sometimes confuse them, but lung cancer develops within the lungs and mesothelioma develops on the lining of the lungs.
How Lung Cancer and Mesothelioma Are Similar
- Diagnosis and treatment: Imaging scans and biopsies help diagnose both mesothelioma and lung cancer. Treatments for both may include surgery, chemo, radiation and immunotherapy.
- Incidence and mortality: Incidence for lung cancer is mostly tied to smoking rates. But like mesothelioma, areas with histories of heavy asbestos use also have higher lung cancer incidence. Death rates are similar between the two cancers as well.
- Similar symptoms: Mesothelioma and lung cancer share symptoms like chest pain, coughing, trouble breathing, fatigue and weight loss.
- Time to develop: Both cancers often have long latency periods. Lung cancer can take 15 to 30 years, and mesothelioma can take 20 to 60 years to develop after asbestos exposure.
In the U.S., lung cancer led to ~124,990 deaths in 2026. Mesothelioma leads to ~2,500 to ~3,000 deaths each year, according to the CDC. Both diseases have a serious mortality risk. But symptoms alone can’t tell a patient which disease they have. The pathology report provides the diagnosis.
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Get Your Free GuideHow Are Mesothelioma and Lung Cancer Diagnosed?
Doctors begin the process of diagnosing mesothelioma and lung cancer in the same way. They start with a physical exam, then order imaging tests like X-rays, CT scans or PET scans. A biopsy is needed to confirm a diagnosis. Your doctor may collect a sample for the biopsy through a bronchoscopy, a needle aspiration or thoracoscopic surgery.
Doctors often misdiagnose mesothelioma as adenocarcinoma first, a type of lung cancer. These cancers can look similar on imaging and under a basic microscope. But pathologists use antibody stains to identify proteins specific to each disease.
Biopsies to Diagnose Lung Cancer or Mesothelioma
- Antibody staining: Pathologists apply special stains to biopsy tissue to identify mesothelioma cells. This process, called immunohistochemistry or IHC, is the standard test for confirming a mesothelioma diagnosis.
- Bronchoscopy: Your doctor inserts a tiny camera down your throat and airways to detect abnormalities like tumors. They may collect and test a cell sample for cancer.
- Needle biopsy: Done under local anesthesia, it involves placing a small needle into the tumor. An ultrasound machine or a CT scan can visualize it.
- Thoracoscopic surgery: A solid tissue sample is collected using a small camera inserted between your ribs. Fluid buildup is suctioned out for testing, but this isn’t a reliable way to confirm a diagnosis.
Both lung cancer and mesothelioma are associated with pleural effusions, or excess fluid in the chest cavity. Sometimes fluid is studied as part of the diagnostic process, but as thoracic surgeon Dr. Jeffrey Velotta explains, “The fluid, the majority of the time, will not tell you if you have mesothelioma or not. There’s just not enough cells in the fluid. And so you actually need tissue.” This is why a biopsy is necessary.
Why Mesothelioma Is Frequently Misdiagnosed
Early mesothelioma symptoms overlap with lung cancer, pneumonia and pleurisy, and its cells can look like adenocarcinoma under a microscope. Patients who suspect asbestos exposure should ask their doctor about a second review with a pathologist experienced with mesothelioma using IHC before starting treatment.
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It is often delayed, in fact. The patients will often present with somewhat non-specific symptoms such as chest pain or shortness of breath or even a cough, and they are found to have fluid outside of the lung but inside of the rib cage. And there are several processes that can cause this, and early on, the first steps to evaluate that are just draining that fluid out and sending it for sampling.
Unfortunately, the sensitivity of tests of that fluid to diagnose mesothelioma is not great, and so the diagnosis is frequently missed. So people will undergo repeated drainage of fluid and not get a diagnosis of cancer at all. Or if they are diagnosed with cancer, unfortunately there are some unique aspects to mesothelioma at a microscopic level that requires some expertise on the part of the pathologist or the person called a cytopathologist, who looks at cells, to evaluate.
In fact, with mesothelioma, it’s often required that some tissue be evaluated, and that has a higher accuracy rate than just the fluid itself. And it really does require experience on the parts of the clinicians, a high index of suspicion on the part of the clinician evaluating the patient, and some expertise among the team–
the pathologists and cytopathologists who are looking at those samples.
How Are Mesothelioma and Lung Cancer Treated?
Mesothelioma and lung cancer are both commonly treated with surgery, chemo, radiation and immunotherapy. But the full treatment picture looks different for each cancer. The FDA has approved far more drug treatments for lung cancer than for mesothelioma and mesothelioma surgery is harder to perform because the tumor typically spreads as a sheet across the lung lining rather than forming one mass.
Clinical trials often test similar therapies for both cancers, including gene therapy, photodynamic therapy and cryotherapy. The 2020 FDA approval of Opdivo (nivolumab) combined with Yervoy (ipilimumab) was the first immunotherapy approval for pleural mesothelioma in 16 years. The current first-line chemo for the disease is Alimta (pemetrexed) combined with cisplatin or carboplatin.
Lung cancer surgery may include a lobectomy that removes the cancerous lobe of the lung. Mesothelioma surgery often involves a pleurectomy and decortication that removes the pleural lining. Dr. Fontaine tells us, “The fundamental difference is the fact that mesothelioma starts in the lining around the lung. It’s more technically challenging and difficult for us to surgically remove the cancer in mesothelioma compared to lung cancer.”
Radiation therapy works for both cancers, though outcomes vary by study and treatment approach. A 2021 mesothelioma study found a 76% 1-year local control rate after radiation. Lung cancer treatment with radiation has generally found comparable 1-year control rates, though results differ across studies and radiation techniques.
Randy Boudreaux
Keytruda Helped Survivor of Mesothelioma and Lung Cancer
When Boudreaux was diagnosed with mesothelioma in 2014, he wasn’t a surgical candidate because of a previous surgery for non-small cell lung cancer. He had a piece of lung removed the year before on the opposite side of the chest from where the mesothelioma was found.
Randy Boudreaux
What’s the Prognosis for Mesothelioma vs. Lung Cancer?
The 5-year relative survival rate is 28% for lung cancer and 15% for pleural mesothelioma. Both improve substantially with early-stage diagnosis and treatment with a specialist. An individual’s outlook depends on age at diagnosis, overall health and response to treatment.
The higher incidence of lung cancer cases means more widespread access to specialized treatment centers and doctors. Mesothelioma is much rarer, leaving people diagnosed with it fewer options to improve their prognosis. People diagnosed with mesothelioma who receive care at specialized mesothelioma treatment centers tend to live significantly longer than those who see general oncologists.
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Get Financial HelpCommon Questions About Mesothelioma Vs. Lung Cancer
- Is mesothelioma a form of lung cancer or considered non-small cell lung cancer?
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No. Mesothelioma isn’t non-small cell lung cancer or any other form of lung cancer. They share similarities, but are distinct cancers. A detailed pathology report will confirm the type of cancer someone has. Request a pathologist who has experience with mesothelioma if you are at risk for it.
As Anna Nowak, internationally renowned asbestos researcher and mesothelioma advocate, tells us, “No, mesothelioma is not the same as lung cancer. Mesothelioma is a cancer of the pleura, which is the lining around the lungs. However, because both lung cancer and mesothelioma arise within the chest cavity (thorax), mesothelioma is sometimes incorrectly called a ‘lung cancer.’ Adding to the confusion, many lung cancer specialists also treat mesothelioma and vice versa.”
- Can mesothelioma be misdiagnosed as lung cancer?
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Yes. Doctors often misdiagnose mesothelioma as adenocarcinoma first, a type of non-small cell lung cancer, because they can look identical on chest imaging and similar under a basic microscope. Pathologists confirm a mesothelioma diagnosis with antibody staining to detect specific proteins. People with known or suspected asbestos exposure should request a second pathology review at a specialty mesothelioma center before starting treatment.
- Can you have both mesothelioma and lung cancer at the same time?
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Yes. People with heavy asbestos exposure can develop both cancers at the same time or one after the other. Doctors may diagnose them simultaneously during imaging or biopsy. A thoracic oncologist typically coordinates treatment for both cancers and addresses the more aggressive cancer first.
- Should you see a mesothelioma specialist if you have asbestos-related lung cancer?
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Yes. A thoracic specialist who regularly treats asbestos-related cancers can confirm whether a tumor is lung cancer or mesothelioma, since the 2 are easy to confuse. Specialty centers also offer access to clinical trials and treatment plans that community hospitals often don’t. A second pathology review at a specialty center is recommended before any patient with known asbestos exposure starts treatment.
- Can asbestos cause lung cancer as well as mesothelioma?
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Yes. Asbestos is the primary cause of mesothelioma and also causes lung cancer, though only roughly 4% of lung cancer diagnoses are attributed to asbestos exposure. Cigarette smoking causes about 84% to 87% of lung cancer cases. Smokers who worked with asbestos are at a higher lung cancer risk than someone with either exposure alone.
- I was diagnosed with lung cancer, but I worked around asbestos. What should I do?
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Tell your doctor about your asbestos exposure history and ask whether a second pathology review is appropriate. Asbestos exposure increases the risk of both lung cancer and mesothelioma, so an asbestos history doesn’t necessarily mean a lung cancer diagnosis is incorrect. In some cases, mesothelioma can resemble adenocarcinoma, a type of non-small cell lung cancer, on imaging and under a basic microscope. Specialized antibody staining can help pathologists distinguish between these cancers. Getting the diagnosis right can affect your treatment plan and legal options.
