Mesothelioma Stages

Once a patient is diagnosed with mesothelioma, doctors use mesothelioma staging to see how far the cancer has spread through the body. Although doctors use certain determinations for severity in all mesothelioma types, pleural mesothelioma is the only type with a formal staging system. Knowing the stage of mesothelioma helps doctors develop the most effective treatment plan to improve prognosis and life expectancy.

What Are Mesothelioma Stages?

A doctor will determine the mesothelioma stage when a patient is first diagnosed. Mesothelioma stages describe the spread and location of cancer throughout the body. This can help doctors figure out the best way to treat the patient and improve their prognosis.

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Registered Nurse Amy Fair discusses the 4 stages of mesothelioma and why it's important to talk to your doctor about mesothelioma staging. View Transcript.

Duration: 1 min 06 sec

What are the stages of mesothelioma?

There are 4 stages of mesothelioma just as there are in most cancers. Stage 1 the mesothelioma is contained within the pleura. Stage 2 the disease has come outside the pleura and invaded into the fatty tissue of lung or the diaphragm. Stage 3 is where it’s metastasized into local organs and stage 4 is where it’s metastasized into distant organs, limp nodes and tissue.

Staging is important in mesothelioma as is in any cancer. It drives your prognosis; it drives your treatment modalities. It’s important to know if you’re a surgical candidate and the staging of your disease drives that decision. It’s important to discuss staging after you’ve had your CT or PET scan with your surgeon or oncologist.

Pleural mesothelioma is the only type that has an official staging system. These stages range from 1 to 4. Stage 1 is the earliest malignant mesothelioma stage with the least cancer spread, while by stage 4, the cancer has spread through the entire body.

Although it has no official staging, peritoneal mesothelioma is sometimes unofficially staged to help patients understand their prognosis.

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Pleural Mesothelioma Stages

Malignant pleural mesothelioma patients make up roughly 80% of all mesothelioma cases, according to the American Cancer Society (ACS). This type of mesothelioma starts in the protective lining of the lungs (pleura) before spreading to other organs.

Pleural mesothelioma can spread through:

  • Tissue: Cancer tumors may spread from the pleura to the tissue of nearby areas such as the chest wall or lungs.
  • Lymph System: Cancer cells can spread through the lymph vessels to the lymph nodes in the armpits, neck, or groin.
  • Blood: Cancer can spread through the blood system and travel throughout the body.

Pleural mesothelioma is the only type of this cancer that has been researched enough to be officially staged using the TNM staging system. Doctors have a better understanding of how pleural mesothelioma develops and metastasizes compared to other types. This staging system helps mesothelioma patients understand the projected outlook of their disease.

*Located in lining of the lungs

Stage 1

  • Earliest stage, during which the cancer has not spread beyond the layers of the pleura.
  • The average life expectancy for stage 1 malignant pleural mesothelioma was about 21 months.

Patients have treatment options that may improve life expectancy by several months or years.

Stage 1 Mesothelioma

*Located in lining of the lungs

Stage 2

  • The cancer has metastasized slightly outside the pleura and possibly into nearby lymph nodes.
  • The average life expectancy for stage 2 mesothelioma is about 19 months.

Patients still have many treatment options to increase life expectancy.

Stage 2 Mesothelioma

*Located in lining of the lungs

Stage 3

  • Mesothelioma has metastasized into nearby tissues, organs, or lymph nodes.
  • The average life expectancy for stage mesothelioma is around 16 months.

Most stage 3 mesothelioma patients are no longer eligible for curative surgeries, but can still undergo treatments to help slow disease spread and manage symptoms.

Stage 3 Mesothelioma

*Located in lining of the lungs

Stage 4

  • The most advanced stage of pleural mesothelioma.
  • The average life expectancy for stage 4 mesothelioma is about 12 months.

At stage 4, the cancer has moved to distant parts of the body. Treatment during this stage is focused on relieving symptoms and giving the patient the best quality of life.

Stage 4 Mesothelioma

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Staging For Other Types of Mesothelioma

There are no official staging systems for the other types of mesothelioma. There is not enough research on other types to create their own staging systems. However, there are ways to note how far other types of mesothelioma have spread.

Peritoneal mesothelioma presents staging challenges since it can progress in an unexpected manner, and often remains in the abdomen instead of spreading to other parts of the body.

Most patients are diagnosed with pericardial mesothelioma, which forms in the heart lining, after their death through an autopsy. Even when individuals receive a diagnosis when they are alive, their cancer is often detected at an advanced stage with a poor prognosis.

Testicular mesothelioma is also extremely rare and has no official staging system. Doctors may look at whether the patient’s mesothelioma has metastasized to determine the individual’s outlook.

Mesothelioma Staging Systems

TNM System

The TNM System is the most commonly used staging system for pleural mesothelioma, according to the ACS. The TNM System is regulated by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC).

The TNM System measures cancer progression based on:

  • Size of the main tumor (T): How far the cancer has spread, whether it has spread to nearby chest areas, and whether it can be removed with surgery
  • Spread to nearby lymph nodes (N): Whether the cancer has spread to nearby lymph nodes
  • Spread (metastasis) to distant sites (M): Whether the cancer has metastasized to the bones, liver, or lung on the other side of the body

Numbers and/or letters after the T, N, and M detail the progression of these three factors. For example, T1 describes a tumor that has not spread widely. Once a doctor determines a patient’s T, N, and M categories, they combine it to assign an overall stage (such as stage 2 mesothelioma).

There are several other mesothelioma staging systems that were previously used to diagnose the disease including the Brigham system, Butchart system, and SEER staging system. Most of these systems are no longer used to diagnose mesothelioma.

Staging for Peritoneal Mesothelioma

In some cases, peritoneal mesothelioma is classified using the SEER system’s LRD model and is classified by local, regional, and distant metastasis.

In 2011, Professor Tristan D. Yan proposed a new “TNM” staging system for peritoneal mesothelioma.

The proposed TNM staging system would be based on:

  • How much the mesothelioma is affecting the patient’s health
  • How far the cancer has spread within the abdomen
  • How far the cancer has spread beyond the abdomen

Even with this proposal, more research is needed before it becomes an official staging system.

Diagnosing Stages of Mesothelioma

Doctors determine a patient’s mesothelioma stage from imaging tests and biopsy results.

Imaging tests such as X-rays, MRI (magnetic resonance imaging) scans, and CT (computed tomography) scans can help doctors see the location and spread of a patient’s mesothelioma.

  • CT scans are detailed images of the body used to diagnose mesothelioma. These scans can also find the exact location and spread to determine the mesothelioma stage.
  • MRI scans use radio waves and powerful magnets to look deep into the body’s tissues. According to the ACS, MRI scans may be especially helpful when determining if pleural mesothelioma has spread to the diaphragm.
  • PET (positron emission tomography) scans use a camera to detect radioactivity in a patient’s body. Before the scan, patients are injected with a low-dose radioactive sugar that is absorbed more quickly by cancer cells. The PET scan image can help see if mesothelioma has spread to lymph nodes or other areas.

Some machines can take PET and CT scans at the same time to allow doctors to compare areas where cancer may be concentrated (PET scan) with a detailed image (CT scan).

By helping doctors determine a patient’s mesothelioma stage, these imaging tests also help doctors decide what treatments will be most effective for a patient

Prognosis of Mesothelioma Stages

A mesothelioma prognosis can be greatly impacted by mesothelioma stage.

As the cancer spreads to other areas, there is a lower chance that the body will respond well to treatment. Due to this, late-stage patients are less likely to achieve long-term survival.

Patients with late-stage mesothelioma will often not qualify for aggressive surgery options that can greatly improve their life expectancy.

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Mesothelioma Treatments by Each Stage

Mesothelioma stage plays a large role when doctors are considering treatment options. The mesothelioma stage may determine if the cancer is resectable and if a patient is healthy enough to undergo major surgery or other invasive cancer treatments.

Doctors may decide to focus mesothelioma treatment on life-extending or palliative options depending on the extent of mesothelioma, the patient’s personal wishes, and other factors.

Stage 1 Treatment

Doctors may recommend closely watching mesothelioma instead of treating it if it is developing slowly and not causing symptoms. Doctors will begin treatment if the cancer begins to grow more quickly or cause symptoms.

Stage 1 mesothelioma may be treated with:

Stage 2 Treatment

Stage 2 mesothelioma patients are often good candidates for curative surgery if the cancer has not spread far into surrounding tissues.

Treatment options for stage 2 mesothelioma include chemotherapy, radiation, and/or surgery.

Surgery may be especially beneficial for early-stage mesothelioma patients. According to the ACS, surgery is more likely to show long-term benefits in early-stage cancers since there is a better chance that most or all of the cancer can be removed.

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Stage 3 Treatment

Stage 3 mesothelioma may be more difficult to treat, especially if it has progressed to stage 3B. Many cases of stage 3 mesothelioma are no longer resectable.

While the ACS reports that mesothelioma doctors do not agree on the effectiveness of chemotherapy or radiation therapy for mesothelioma, they are often used as the main treatments for patients who cannot undergo surgery. These treatments may extend life or relieve symptoms.

However, some stage 3 patients are still candidates for curative surgery. The ACS states that surgery may be helpful for late-stage patients, but the benefits are more likely to last a short time.

Stage 4 Treatment

Stage 4 mesothelioma cannot be removed completely with surgery because the cancer is no longer contained in one area. Chemotherapy is usually the main treatment for stage 4 mesothelioma to relieve symptoms and potentially shrink or slow cancer growth.

Patients may also benefit from newer or experimental treatments through clinical trials since treatment for stage 4 mesothelioma is often limited.

Other stage 4 mesothelioma treatments may include:

Further, patients can seek palliative treatment to reduce pain and discomfort caused by mesothelioma rather than extend life expectancy.

Palliative stage 4 mesothelioma treatments may include:

  • Medication: May help relieve pain
  • Pleurodesis: May reduce fluid buildup by sealing the space between the chest cavity and outer lung lining
  • Radiation: May help shrink tumors and relieve pain through high-energy rays
  • Thoracentesis/paracentesis: May reduce fluid buildup through removal from a minimally invasive needle

Get Treatment at Any Mesothelioma Stage

Mesothelioma stage is an important factor in determining a patient’s cancer outlook and treatment plan.

Most mesothelioma patients are diagnosed at a later stage when it is too late for aggressive and curative treatments. However, emerging treatment options such as immunotherapy and targeted therapy continue to improve and become available to more patients.

As research continues, patients with all stages of mesothelioma may look forward to longer, healthier lives.

Use our free Mesothelioma Specialist Match Program to find a doctor near you to get the best and most effective treatment for your condition.

Mesothelioma Stages FAQs

How many stages of mesothelioma are there?

There are 4 stages of pleural mesothelioma according to the TNM system. These 4 stages help doctors determine the spread and extent of mesothelioma in the body to find the best and most effective treatment option.

What happens in the final stages of mesothelioma?

During the final stages of mesothelioma, the cancer has spread to other areas of the body and can longer be operated on. Late-stage mesothelioma patients are not eligible to undergo curative surgery options and are often treated with palliative care.

What are the symptoms of advanced mesothelioma?

Advanced mesothelioma symptoms may include:

  • Abdominal pain
  • Bloating
  • Chest pain
  • Coughing up blood
  • Excessive sweating
  • Extreme weight loss
  • Fatigue
  • Fever
  • Shortness of breath

These late-stage mesothelioma symptoms are caused by significant cancer spread throughout the body.

Can mesothelioma go into remission?

Yes. It is possible for mesothelioma symptoms to decrease or completely disappear. Curative treatment options can help achieve mesothelioma remission. As the mesothelioma progresses into the later stages, it can become difficult to reach remission.

Reviewed by:Dr. Assuntina Sacco

Board-Certified Oncologist

  • Fact-Checked
  • Editor

Assuntina Sacco, MD is an Associate Professor of Internal Medicine at the University of California, San Diego (UCSD) Moores Cancer Center, where she also serves as the Medical Director of Infusion Services. She is a board-certified medical oncologist trained to treat all solid tumor types, with the use of chemotherapy, immunotherapy, targeted therapy, and clinical trials.

Dr. Assuntina Sacco is an independently paid medical reviewer.

Mesothelioma Hope was founded by a team of advocates to educate people about this aggressive form of cancer. Mesothelioma affects thousands of people each year. We help give hope to those impacted by mesothelioma.

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  3. Kim, J., Bhagwandin, S., & Labow, D. (2017, April 20). Malignant peritoneal mesothelioma: A review. Retrieved August 12, 2021, from
  4. Malignant mesothelioma STAGES. (n.d.). Retrieved August 12, 2021, from
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  7. Schapira, L. (2021, March 11). When not treating "cancer" is the best treatment plan. Retrieved August 12, 2021, from
  8. Summary staging manual - 2018. (n.d.). Retrieved August 12, 2021, from
  9. Treatment of mesothelioma based on the extent of the cancer. (n.d.). Retrieved August 12, 2021, from
  10. Watson, S. (2018, March 23). Pleurodesis: Complications, side effects, and recovery. Retrieved August 17, 2021, from,building%20up%20around%20your%20lungs.
  11. Yan, T. D., Deraco, M., Elias, D., Glehen, O., Levine, E. A., Moran, B. J., . . . Sugarbaker, P. H. (2010). A novel tumor-node-metastasis (TNM) staging system of DIFFUSE malignant peritoneal Mesothelioma USING OUTCOME analysis of A multi-institutional database*. Cancer, 117(9), 1855-1863. doi:10.1002/cncr.25640
  12. Zhang, N., Fu, N., Peng, S., & Luo, X. (2017, December 01). Malignant mesothelioma of the TUNICA vaginalis TESTIS: A case report and literature review. Retrieved August 12, 2021, from

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