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Mesothelioma Stages

The four stages of pleural mesothelioma refer to how far the cancer has spread. Doctors use this information to determine prognosis and life expectancy. The mesothelioma stage plays a major role in whether a patient is eligible for tumor-removing surgery.

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In stages 1 and 2 of pleural mesothelioma, tumors are contained in one place in the chest and may affect nearby lymph nodes.

Stage 3 involves major growth of the primary tumor or spread to distant lymph nodes.

In stage 4, secondary tumors develop in other parts of the body.

Patients diagnosed with early-stage pleural mesothelioma tend to live longer.

Many other factors affect life expectancy, though, and some late-stage patients survive for years with treatment.

The American Cancer Society reports two- and five-year survival rates for pleural mesothelioma based on stage at diagnosis.

The data is based on thousands of patients diagnosed between 2000 and 2013[1].

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Pleural Mesothelioma Two- and Five-Year Survival Rates by Stage

Stage 2-Year Survival Rate 5-Year Survival Rate
Stage 1A 46% 16%
Stage 1B 41% 13%
Stage 2 38% 10%
Stage 3A 30% 8%
Stage 3B 26% 5%
Stage 4 17% Less than 1%

Patients in stage 1 or 2 may be eligible for tumor-removing surgery. When combined with other therapies, surgery offers the best chance of extending survival. Stage 3 patients are sometimes eligible, but as the cancer becomes more advanced, treatment options become more limited[2].

Tumor-removing surgery is usually not an option for stage 4 pleural mesothelioma patients.

Mesothelioma Staging System

The most widely used staging system for pleural mesothelioma was developed by the International Mesothelioma Interest Group[3]. It is based on the common TNM cancer staging framework, where the three letters stand for tumor, nodes and metastasis[4].

During the diagnostic process, doctors do their best to determine the cancer stage based on imaging scans and biopsy results. With these less invasive techniques, mesothelioma experts can come close to estimating a patient’s cancer stage.

But looking inside the patient’s chest during surgery is still the most accurate way to stage pleural mesothelioma. In many cases, patients are diagnosed with one stage, but then surgeons discover the cancer is a different stage when they actually get a look at the tumor growth.

For this reason, many pleural mesothelioma surgeons prefer to use a camera probe to look inside a patient’s chest before going through with a highly invasive surgery.

If the camera probe reveals much more cancer spread than expected, the surgeon can cancel the surgery before opening the patient’s chest. This spares the patient from undergoing an aggressive treatment that would have little benefit.

Stage 1 Pleural Mesothelioma

Pleural mesothelioma starts in a spot outside the surface of one lung. Early-stage mesothelioma typically does not cause symptoms, so it is rarely diagnosed in stage 1. Patients fortunate to be diagnosed this early usually have a more favorable prognosis.

Stage 1A Definition

T1, N0, M0: Cancer is in one or both layers of the pleura (membrane lining of the lungs) on one side of the chest.

Stage 1B Definition

T2-T3, N0, M0: Cancer is in both layers of the pleura and other nearby tissue on one side of the chest.

Stage 2 Pleural Mesothelioma

Symptoms may start to arise in stage 2 pleural mesothelioma, though people often mistake these early signs for cold or flu symptoms. While there is a little more cancer spread at stage 2, the treatment options are generally the same as stage 1.

Stage 2 Definition

T1-T2, N1, M0: Cancer is in the pleura and possibly some nearby tissue on one side of the chest. In addition, cancer has spread to nearby lymph nodes.

Stage 3 Pleural Mesothelioma

Stage 3 pleural mesothelioma has spread significantly throughout the chest, causing distinct cancer symptoms. Whether doctors recommend surgery depends on how far the cancer has spread and several other factors.

Stage 3A Definition

T3, N1, M0: Cancer has spread from the pleura into other tissue on one side of the chest. The cancer has also spread to nearby lymph nodes.

Stage 3B Definition

T4, Any N, M0 or T1–T3, N2, M0: Cancer has spread from the pleura deep into other parts of the chest, or it has spread to lymph nodes on the other side of the chest or above the collarbone.

Stage 4 Pleural Mesothelioma

In the last stage of pleural mesothelioma, the cancer has metastasized. This means cancer cells have broken away from the original tumor and invaded organs, bones and tissues around the body. Stage 4 pleural mesothelioma is very difficult to treat, and symptoms are severe.

Stage 4 Definition

Any T, Any N, M1: Cancer has spread to distant parts of the body, starting new tumors separate from the original site in the pleura.

Snehal Smart, M.D.

Snehal Smart, M.D.

Snehal Smart is the Pleural Mesothelioma Center’s in-house medical doctor, serving as both an experienced Patient Advocate and an expert medical writer for the website. When she is not providing one-on-one assistance to patients, Dr. Snehal stays current on the latest medical research, reading peer-reviewed studies and interviewing oncologists to learn about advancements in diagnostic tools and cancer treatments.

Medically Reviewed By Dr. Joanne Getsy
Last Modified March 13, 2019

5 Cited Article Sources

  1. American Cancer Society. (2017, December 20). Survival Statistics for Mesothelioma. Retrieved from
  2. American Cancer Society. (2016, February 17). Treatment of Mesothelioma Based on the Extent of the Cancer. Retrieved from
  3. Bonomi, M. et al. (2017). Clinical staging of malignant pleural mesothelioma: Current perspectives. Lung Cancer: Targets and Therapy, 8, 127-139. doi: 10.2147/LCTT.S102113
  4. American Cancer Society. (2017, December 20). Malignant mesothelioma stages. Retrieved from
  5. Nowak, A. et al. (2016, December). The IASLC Mesothelioma Staging Project: Proposals for Revisions of the T Descriptors in the Forthcoming Eighth Edition of the TNM Classification for Pleural Mesothelioma. Retrieved from

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