Malignant Mesothelioma: Stages

March 21, 2017

Malignant Mesothelioma: Stages

What does stage of cancer mean?

The stage of a cancer is how much and how far the cancer has spread in your body. Your healthcare provider uses exams and tests to find out the size of the cancer and where it is. He or she can also see if the cancer has grown into nearby areas, and if it has spread to other parts of your body. The stage of a cancer is one of the most important things to know when deciding how to treat the cancer.

What are the stages of malignant mesothelioma?

At this time, mesothelioma in the chest (pleural mesothelioma) is the only type that has a formal staging system. This is because it’s the most common form of this cancer. The other types of this cancer, including peritoneal mesothelioma (which starts in the abdomen), don’t have formal staging systems.

The American Joint Committee on Cancer staging system uses Roman numerals from I to IV (1 to 4) for the different stages:

In Stage I, the following is true:

  • The cancer is on one side of the body in the lining of the chest cavity near the lung. It may also include the lining of the lung, area between the lungs (mediastinum), or the breathing muscle that separates the chest rom the abdomen (diaphragm).

  • The cancer has not spread to the lymph nodes or to distant parts of the body.

Stage II includes the following:

  • The cancer involves the lining of the chest wall on one side of the chest. It also involves the lining of the lung, diaphragm, and the mediastinum. The cancer has also grown into the diaphragm or lung as well.

  • The cancer has still not spread to lymph nodes or distant sites. 

Stage III is any of the following:

  • The cancer has spread into the lymph nodes that drain the chest and the lung on the same side of the body.

  • The cancer has moved into the heart sac or the space between the lungs.

  • The cancer has moved into the chest wall in one spot. 

Stage IV is the following:

  • The cancer has spread through the diaphragm into the belly, to deep layers of the chest wall, or to organs between the lungs (including the heart). Or the cancer has spread to the other side of the chest or other lung, to lymph nodes near the collarbone or on the other side of the chest, or to distant organs or tissues.

Stage I and II often have smaller tumors than stages III and IV. The size and stage of the tumor can help your healthcare provider decide treatment.

Talking with your healthcare provider

Once your cancer is staged, your healthcare provider will talk with you about what the stage means for your treatment. Make sure to ask any questions or talk about your concerns.


March 21, 2017


Clinical Presentation, Diagnosis, and Staging of Malignant Pleural Mesothelioma, UpToDate

Reviewed By:  

Alteri, Rick, MD,Levin, Mark, MD