Mesothelioma Stages

Once a patient is diagnosed, doctors use mesothelioma staging (1-4) to describe how far the cancer has spread through the body. Pleural mesothelioma is the only type with a formal staging system, although specialists can still determine the severity of other mesothelioma types. Knowing the stage of a patient’s mesothelioma helps doctors develop the most effective treatment plan to improve their prognosis and quality of life.

Fact-Checked and Medically Reviewed By: Dr. Mark Levin

What Are the 4 Stages of Mesothelioma?

Mesothelioma stages are used to categorize the spread and location of this cancer throughout the body. A doctor will determine the stage of a patient’s mesothelioma when they are first diagnosed. The doctor can then identify cancer treatments that are best suited to the cancer’s stage and can potentially improve the patient’s prognosis.

Stages of Mesothelioma Video Thumbnail

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 of the cancer with an official staging system.

Pleural mesothelioma stages range from 1 to 4.

Stage 1 is the earliest malignant mesothelioma stage with the least cancer spread. By stage 4, the cancer has spread through the entire body. How quickly mesothelioma spreads depends on each patient.

Although peritoneal mesothelioma doesn’t have an official staging system, doctors can let patients know how advanced the cancer is to help them better understand their prognosis.

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Pleural Mesothelioma Stages

Pleural mesothelioma makes 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).

Pleural mesothelioma can spread through:

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

Pleural mesothelioma is the only type of this cancer that has been researched enough to be officially staged using the tumor-node-metastasis (TNM) staging system. This staging system helps mesothelioma patients understand the projected outlook of their disease.

*Located in lining of the lungs

Stage 1 Mesothelioma

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

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

Learn More About Stage 1 Mesothelioma

*Located in lining of the lungs

Stage 2 Mesothelioma

  • 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.

Learn More About Stage 2 Mesothelioma

*Located in lining of the lungs

Stage 3 Mesothelioma

  • Mesothelioma has metastasized considerably 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.

Learn More About Stage 3 Mesothelioma

*Located in lining of the lungs

Stage 4 Mesothelioma

  • This is 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.

Learn More About Stage 4 Mesothelioma

We can help you connect with a mesothelioma specialist in your area.

Use our Free Mesothelioma Doctor Match to get started on your treatment journey.

Staging for Other Types of Mesothelioma

There are no official staging systems for the other types of mesothelioma because there is not enough research on these rarer forms of the disease. However, there are ways to note how far other types of mesothelioma have spread.

Diagnosing peritoneal mesothelioma stages is challenging since it can progress in an unexpected manner, often remaining in the lining of the abdomen (peritoneum) without spreading to distant organs.

Pericardial mesothelioma, which forms in the heart lining, is most often diagnosed after death through an autopsy.

Testicular mesothelioma is extremely rare and has no official staging system. Doctors may look at whether the patient’s mesothelioma has spread beyond the lining of the testes to determine their prognosis.

Mesothelioma Treatments By Stage

A doctor speaks with a patient about mesothelioma stages

Mesothelioma stage plays a large role when doctors are considering treatment options. The mesothelioma stage may determine if the cancer is resectable (can be removed by surgery) 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 (symptom-relieving) options depending on the extent of mesothelioma, the patient’s personal wishes, and other factors.

Stage 1 Mesothelioma Treatment

Doctors may recommend closely watching mesothelioma instead of treating it if the disease is developing slowly and not causing symptoms. If the cancer begins to grow more quickly or cause symptoms, the patient’s mesothelioma doctor will determine the best treatment.

Stage 1 mesothelioma may be treated with:

Stage 2 Mesothelioma Treatment

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

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

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

Stage 3 Mesothelioma Treatment

Stage 3 mesothelioma may be more difficult to treat, especially if it has progressed to stage 3B, which indicates a farther spread than 3A. 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 have surgery. These treatments may extend a patient’s life or alleviate their 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 Mesothelioma 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, potentially shrink or slow cancer growth, and improve quality of life.

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:

  • Immunotherapy
  • Targeted therapy
  • Tumor treating fields (TTF or TTFields)

Patients can also seek palliative treatment to reduce pain and discomfort caused by mesothelioma rather than extend life expectancy.

Palliative stage 4 mesothelioma treatments may include:

  • Medication to help relieve pain
  • Pleurodesis to decrease fluid buildup by sealing the space between the chest cavity and outer lung lining
  • Radiation to help shrink tumors and relieve pain through high-energy rays
  • Thoracentesis/paracentesis to help reduce fluid buildup by removing it with a small needle

Request your Free Mesothelioma Guide today to learn more about mesothelioma stages, treatment, and resources for patients battling this cancer.

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Mesothelioma Staging Systems

TNM System

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

The TNM staging system measures cancer progression based on the:

  • 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 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 them to assign an overall stage (such as stage 2 mesothelioma).

Several other mesothelioma staging systems were previously used to diagnose the disease, including the Brigham system, Butchart system, and SEER staging system. However, most of these systems are no longer used to diagnose mesothelioma.

Staging for Peritoneal Mesothelioma

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

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

The proposed TNM staging system for peritoneal mesothelioma is based on:

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

More research is needed before this proposal becomes an official staging system. In the meantime, doctors can stage peritoneal mesothelioma patients using the peritoneal cancer index (PCI).

The PCI involves examining 13 regions of the abdomen and assigning each a score of 0-3 based on the largest tumor size. Scores range from 0 to 39. A higher score indicates that the patient’s peritoneal mesothelioma is more widespread.

Diagnosing Stages of Mesothelioma

Doctors use imaging tests and biopsy results to make a mesothelioma diagnosis.

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 also help doctors find the exact cancer location and spread to determine the mesothelioma stage.
  • MRI scans use powerful magnets to look deep into the body’s tissues. According to the ACS, MRI scans may be 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 absorbed more quickly by cancer cells. The PET scan image can help doctors see if mesothelioma has spread to the lymph nodes or other areas.

Doctors often take PET and CT scans simultaneously to compare areas where the cancer appears to be concentrated (PET scan) with a more detailed image (CT scan).

These imaging tests are a critical part of a mesothelioma diagnosis since they help doctors decide what treatments will be most effective for each patient’s mesothelioma stage.

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Prognosis of Mesothelioma Stages

A mesothelioma prognosis can be greatly impacted by the stage of the cancer. As the cancer spreads to other areas, there is less of a chance that the body will respond well to treatment. As a result, late-stage mesothelioma patients are less likely to achieve long-term survival.

Additionally, patients with late-stage mesothelioma may not qualify for aggressive surgery options that can greatly increase their life expectancy.

Mesothelioma life expectancy describes how long you can expect to live after being diagnosed. Life expectancy depends on a patient’s age, the type and stage of their mesothelioma, and overall health. Patients with early-stage mesothelioma have higher survival rates than those with advanced mesothelioma.

Life Expectancy by Stage
StageLife Expectancy
Stage 121 months
Stage 216 months
Stage 319 months
Stage 412 months

Find Targeted Mesothelioma Treatment Today

The mesothelioma stage is important in determining a patient’s cancer outlook and treatment plan.

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

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

Get matched with a local doctor for free to start treatment targeted to your mesothelioma stage.

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 so they can identify the most effective treatment option(s).

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 have curative surgery and are often treated with palliative care to relieve their symptoms.

What are symptoms of the end stages of 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 mesothelioma progresses into the later stages, it can become more difficult to reach remission.

Reviewed by:Dr. Mark Levin

Certified Oncologist and Hematologist

  • Fact-Checked
  • Editor

Mark Levin, MD has over 30 years of experience in academic and community hematology and oncology. In addition to serving as Chief or Director at four different teaching institutions throughout his life, he is also still a practicing clinician, has taught and designed formal education programs, and has authored numerous publications in various fields related to hematology and oncology.

Dr. Mark Levin is an independently paid medical reviewer.

  • Board Certified Oncologist
  • 30+ Years Experience
  • Published Medical Author
Written by:

Lead Editor

Laura Wright is a journalist and content strategist with more than 15 years of professional experience. She attended college at the University of Florida, graduating magna cum laude with a bachelor’s degree in journalism in 2008. Her writing has been featured in The Gainesville Sun and other regional publications throughout Florida.

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  10. Watson, S. (2018, March 23). Pleurodesis: Complications, side effects, and recovery. Retrieved February 13, 2023, 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. Ye Z, Yu P, Cao Y, Chai T, Huang S, Cheng X, Du Y. Prediction of Peritoneal Cancer Index and Prognosis in Peritoneal Metastasis of Gastric Cancer Using NLR-PLR-DDI Score: A Retrospective Study. Cancer Manag Res. 2022 Jan 12;14:177-187. doi: 10.2147/CMAR.S343467. PMID: 35046725; PMCID: PMC8763204.

  13. 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 February 13, 2023, from

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