This page was reviewed under our medical and editorial policy by
Dhivya Prabhakar, MD, Medical Oncologist
This page was updated on July 5, 2023.
Currently, only pleural mesothelioma is described by the TNM staging system by the American Joint Committee on Cancer (AJCC) because the other types of mesothelioma are rarer. The TNM staging system for mesothelioma focuses on three important factors for understanding the spread and development of cancer.
TNM staging stands for the three cancer characteristics listed below.
T (tumor): This describes the size of the original tumor.
N (node): This indicates whether the cancer is present in the lymph nodes.
M (metastasis): This refers to whether the cancer has spread to other parts of the body.
Each factor is assessed and rated on a scale, with 0 indicating there's no evidence of a tumor or spread and increasing numbers correlate with increasing severity of that particular factor.
The care team determines the pleural mesothelioma stage so they can use that information, along with the patient’s medical history, family history and other factors, to develop an individualized treatment plan.
The American Cancer Society (ACS) outlines the most recent AJCC staging, as listed below.
The cancer is localized to either the right or left of the pleura lining, a thin membrane that surrounds the chest cavity and lungs. The cancer has not metastasized (spread) to lymph nodes nearby or distant areas of the body.
Stage 1 is divided into substages 1A and 1B.
1A: 1A means T1, N0, M0.
Mesothelioma is found in the pleura that lines the chest wall on one chest side. In addition, 1A means the following sites may or may not also be affected (T1):
Also:
1B: 1B means T2, N0, M0 OR T3, N0, M0.
1B means that mesothelioma has spread more than 1A. There are two 1B groupings:
T2, N0, M0
In the 1B group T2, N0, M0, in addition to mesothelioma developing in the pleura that lines the chest wall on one chest side, mesothelioma has also spread to:
The cancer has also spread into the lung or the diaphragm (T2). However, it hasn’t spread to nearby lymph nodes (N0), and there are no signs of spread to distant body parts (M0).
T3, N0, M0
In the 1B group T3, N0, M0, mesothelioma has spread to nearby areas, but it may still be potentially removed with surgery (T3).
In addition to the pleura that lines the chest wall on one side, mesothelioma has also grown into:
In addition, the tumor has spread to at least one of the following sites:
However, no cancer has spread to nearby lymph nodes (N0) nor to distant body parts (M0).
The cancer affects either the right or left pleural lining and may have spread to a lung or the diaphragm. Distant lymph nodes are not affected, but cancer cells may be present in nearby lymph nodes on the side of the body where the original tumor is located.
Other areas within the chest may now be involved. The cancer may extend into the chest wall and may or may not have spread to the lymph nodes.
As with stage 1, stage 3 is divided into two substages: 3A and 3B.
3A: 3A means T3, N1, M0.
The cancer has spread to nearby structures, but it’s still potentially removable with surgery (T3).
In addition to the pleura that lines the chest wall on one side, the tumor has also spread to:
The tumor has also spread to at least one of the following sites:
While the cancer has spread to nearby lymph nodes on the same side of the body as the original tumor (N1), it hasn’t spread to distant body parts (M0).
3B: 3B means T1-T3, N2, M0 OR T4, any N, M0.
T1-T3, N2, M0
In the 3B group T1-T3, N2, M0, the cancer may or may not have spread to nearby areas, and may still be potentially removed with surgery (T1-T3).
Also, the cancer has spread to nearby lymph nodes on the opposite side of the body as the main tumor, or to the lymph nodes above the collarbone (the supraclavicular lymph nodes) on either side of the body (N2).
No spread to distant body parts is detected (M0).
T4, any N, M0
In the 3B group T4, any N, M0, the cancer has spread so far that surgery may not remove it completely. The tumor is in:
In addition, the tumor has spread to one or more of the following sites:
The cancer may or may not have spread to any of the nearby lymph nodes (any N), but not to distant body parts (M0).
The cancer may have spread across the chest or to nearby lymph nodes, and has spread to distant sites, such as the other lung, the liver or bones. Stage 4 pleural mesothelioma is also referred to as metastatic mesothelioma.
Using the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database, the ACS tracks five-year relative survival rates for patients with the same type and stage of malignant pleural mesothelioma against people in the general population.
According to the ACS, the five-year relative survival rate for malignant pleural mesothelioma (MPM) for all stages is 12 percent. Broken down by how far the cancer has spread, the survival rates are listed below.
Localized MPM: The five-year relative survival rate for those with MPM that’s confined to the pleura is 24 percent.
Regional MPM: The five-year relative survival rate for those with MPM that has spread to nearby structures or lymph nodes is 16 percent.
Distant MPM: The five-year relative survival rate for those with MPM that has spread to distant body parts is 7 percent.
A patient’s cancer stage is a key factor in predicting survival rates, but it’s not the only indicator. Other factors that may be associated with longer survival times in those with MPM include:
Next topic: How is mesothelioma diagnosed?