The stages of mesothelioma

This page is about mesothelioma staging. It is important to remember that the staging for mesothelioma in the chest (pleural mesothelioma) is different to the staging for mesothelioma in the abdomen (peritoneal mesothelioma). There is information about

A quick guide to what's on this page
What staging is
Pleural mesothelioma stages
The IMIG system
Peritoneal mesothelioma stages

The stages of mesothelioma

The staging of pleural mesothelioma is different to the staging of peritoneal mesothelioma.

Pleural mesothelioma stages

In the UK, the system that is most commonly used to stage pleural mesothelioma is the International Mesothelioma Interest Group (IMIG) system.

The IMIG system is based on the TNM staging system. The TNM system describes the extent of the primary tumour (T), whether or not there is cancer in nearby lymph nodes (N), and whether or not the cancer has spread elsewhere - metastases (M).

Once the TNM categories have been decided, this information is grouped together to give the stage. Stage 1 is the earliest stage and stage 4 is the most advanced stage. Further down in this page there is more information about the different stages.

Peritoneal mesothelioma stages

There is no established staging system for peritoneal mesothelioma. If your cancer is staged, it may be done according to the TNM system. The TNM system is the staging system most commonly used in cancer.

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The stage of a cancer tells the doctor how far it has spread. The tests and scans you have when diagnosing your cancer give some information about the stage. Knowing the stage helps your doctor decide about the treatment you need. Most people who are diagnosed with mesothelioma have an advanced stage of cancer.

The staging system most commonly used in the UK for pleural mesothelioma is called the International Mesothelioma Interest Group (IMIG) system.

This is based on the TNM staging system.

The TNM system is the staging system most commonly used in cancer staging generally. The TNM system describes

The size and position of the mesothelioma primary tumour (T)
Whether the mesothelioma cells have spread to nearby lymph nodes (N)
Whether the mesothelioma cells have spread to other parts of the body - metastases (M)

Once the TNM categories have been decided, this information is grouped together to give the stage. Stage 1 is the earliest stage and stage 4 is the most advanced stage.

Stage 1a mesothelioma affects the outer layer of the pleura around the chest wall, on one side of the chest only. It may have grown into the pleural tissue covering the diaphragm
Stage 1b mesothelioma has started to spread to the inner pleural layer (closest to the lungs), but is only on one side of the chest and has not spread into the lung tissue or diaphragm
Stage 2 mesothelioma has spread to both layers of the pleura on one side of the body, and has enlarged to form a tumour mass on the pleural tissue around the lungs, or has started to spread into the diaphragm muscle or the lung tissue
Stage 3 mesothelioma has spread to the chest wall or the covering of the heart (pericardium), but is still potentially removable by surgery. Or it has spread to the lymph nodes on the same side of the chest
Stage 4 mesothelioma cannot be removed by surgery because it has spread to different parts of the chest wall, or has grown through the diaphragm into the peritoneum, or to the pleura on the other side of the body, or to the chest organs, or through to the inner layer of the pericardium. Or it has spread to the lymph nodes on the other side of the chest, or above the collarbone. Or has spread to other parts of the body

There is no established staging system for peritoneal mesothelioma. If your cancer is staged it may be done according to the TNM system. The TNM system is the staging system most commonly used in cancer. The TNM system describes the extent of the primary tumour (T), whether the cancer has spread into lymph nodes close to the tumour (N), and whether the cancer has spread to another part of the body (M).