Stages of pleural mesothelioma

Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, which parts of the organ have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).

Pleural mesothelioma starts in the lining (membrane) that protects and cushions the lungs (called the pleura). The most common staging system for pleural mesothelioma is the TNM system. For this type of cancer, there are 4 stages. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.

The Pleura of the Lungs
The Pleura of the Lungs

Only pleural mesothelioma is staged using the TNM system. There is no staging system for mesothelioma of the lining of the abdomen (peritoneal mesothelioma) or for rare types of mesothelioma.

Find out more about staging cancer.

Stage 1A

Cancer is in the lining of the chest wall (parietal pleura) or the lining covering the lung (visceral pleura) on the same side of the chest as the tumour.

Stage 1B

Cancer is in the parietal or visceral pleura on the same side of the chest as the tumour. It has also spread to at least one of the following:

  • the diaphragm
  • the tissues of the lung

OR

Cancer is in the parietal or visceral pleura on the same side of the chest as the tumour. It has grown into at least one of the following:

  • the connective tissue (fascia) that makes up part of the chest wall
  • the fat in the space between the lungs
  • the soft tissues of the chest wall (but only one area)
  • the lining of the heart (the pericardium) but not all of the way through it

Stage 2

Cancer is in the lining of the chest wall or the lining covering the lung on the same side of the chest as the tumour. It may have also grown into at least one of the following:

  • the diaphragm
  • the tissues of the lung

Cancer has spread to the lymph nodes within the chest on the same side of the body as the tumour.

Stage 3A

Cancer is in the parietal or visceral pleura on the same side of the chest as the tumour. It has grown into at least one of the following:

  • the connective tissue that makes up part of the chest wall
  • the fat in the space between the lungs
  • the soft tissues of the chest wall (but only one area)
  • the lining of the heart but not all of the way through it

Cancer has also spread to the lymph nodes within the chest on the same side of the body as the tumour.

Stage 3B

Cancer is in the lining of the chest wall or the lining covering the lung on the same side of the chest as the tumour. It may have also grown into at least one of the following:

  • the diaphragm
  • the tissues of the lung
  • the connective tissue that makes up part of the chest wall
  • the fat in the space between the lungs
  • the soft tissues of the chest wall (but only one area)
  • the lining of the heart but not all of the way through it

Cancer has spread to the lymph nodes on the other side of the chest from the tumour.

OR

Cancer is found in the parietal or visceral pleura on the same side of the chest as the tumour. It has also grown into at least one of the following:

  • the chest wall and may have grown into the ribs
  • the peritoneum
  • the parietal or visceral pleura on the other side of the chest
  • the esophagus, windpipe (trachea), heart or large blood vessels in the space between the lungs (mediastinum)
  • the bones of the spine (vertebrae)
  • the spinal cord
  • through the lining of the heart

Stage 4

The cancer has spread to other parts of the body (called distant metastasis), such as to the lung on the other side of the body, liver or bones. This is also called metastatic pleural mesothelioma.

Recurrent mesothelioma

Recurrent mesothelioma means that the cancer has come back after it has been treated. It can come back in the part of the body where mesothelioma starts, including the pleura, peritoneum, pericardium or the lining that covers the testicles (tunica vaginalis). If it comes back in the same place, it’s called local recurrence. If it comes back in tissues or lymph nodes close to where it first started, it’s called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.

Expert review and references

  • American Cancer Society. Malignant Mesothelioma. Atlanta, GA: American Cancer Society; 2010.
  • Mesothelioma. American Society of Clinical Oncology (ASCO). Cancer.Net. Alexandria, VA.: American Society of Clinical Oncology (ASCO); 2010.
  • Brierley JD, Gospodarowicz MK, Wittekind C (eds.). TNM Classification of Malignant Tumours. 8th ed. Wiley Blackwell; 2017.

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on cancer.ca, nor do we endorse any service, product, treatment or therapy.


1-888-939-3333 | cancer.ca | © 2024 Canadian Cancer Society