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Mesothelioma

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Stages of pleural mesothelioma

Staging is a way of describing or classifying a cancer based on the extent of cancer in the body. The most common staging system for pleural mesothelioma is the TNM system. The International Union Against Cancer (UICC) uses the TNM system to describe the extent of many solid tumour cancers.

There is no established staging system for peritoneal mesothelioma.

TNM

TNM stands for tumour, nodes, metastasis. TNM staging describes:

  • the size and extent of the primary tumour
  • the number and location of any regional lymph nodes that have cancer cells in them
  • whether the cancer has spread or metastasized to another part of the body

Primary tumour (T)

TX

Primary tumour cannot be assessed

T0

No evidence of primary tumour

T1

Tumour involves the parietal pleura on one side of the chest (ipsilateral parietal pleura), with or without focal involvement of the visceral pleura.

  • T1a – Tumour involves the ipsilateral parietal pleura and may also be in the pleura lining the diaphragm or the mediastinum. There is no tumour in the visceral pleura.
  • T1b – Tumour involves both the ipsilateral parietal pleura and the visceral pleura.

T2

Tumour involves any of the pleural surfaces on one side of the chest (ipsilateral pleura), with at least one of the following:

  • a tumour in the visceral pleura, including the fissures of the lung (which divide the lung into lobes)
  • invasion of the diaphragm
  • invasion of the lung tissue (lung parenchyma)

T3*

Tumour involves any of the pleural surfaces on one side of the chest (ipsilateral pleura), with at least one of the following:

  • invasion of the first layer of the chest wall (endothoracic fascia)
  • invasion into mediastinal fat
  • a single (solitary) tumour invading soft tissues of the chest wall
  • tumour on the surface of the sac that surrounds the heart (non-transmural involvement of the pericardium)

T4*

Tumour involves any of the pleural surfaces on one side of the chest (ipsilateral pleura), with at least one of the following:

  • several areas of invasion (diffuse or multifocal invasion) of soft tissues of the chest wall
  • rib involvement
  • invasion through the diaphragm and into the peritoneum
  • invasion of any organ in the mediastinum
  • extension to the pleura on the side of the chest opposite the tumour (contralateral pleura)
  • invasion into the spine
  • extension to the internal surface of the pericardium
  • a buildup of fluid in the chest (pericardial effusion) with positive cytology (cancer cells in the pericardial fluid)
  • invasion of heart muscle (myocardium)
  • invasion of nerves of the brachial plexus, which control the arm

*Note: T3 describes mesothelioma that is locally advanced but potentially resectable (operable). T4 describes mesothelioma that is locally advanced, but unresectable (not operable).

Regional lymph nodes (N)

NX

Regional lymph nodes cannot be assessed

N0

No regional lymph node metastasis

N1

Metastasis in either or both the bronchopulmonary lymph nodes and the hilar lymph nodes on the same side of the chest as the cancer (ipsilateral lymph nodes).

  • Bronchopulmonary lymph nodes are within the lungs.
  • Hilar lymph nodes are near where the bronchus enters the lung.

N2

Metastasis in subcarinal lymph nodes and in either the internal mammary lymph nodes or mediastinal lymph nodes on the same side of the chest as the cancer.

Or

Metastasis in subcarinal lymph nodes or in either the internal mammary lymph nodes or mediastinal lymph nodes on the same side of the chest as the cancer.

  • Subcarinal lymph nodes are below the windpipe (trachea).
  • Internal mammary lymph nodes are around the breastbone (sternum).
  • Mediastinal lymph nodes are in the centre of the chest between the lungs (mediastinum).

N3

Metastasis in the mediastinal, internal mammary or hilar lymph nodes on the opposite side of the chest as the cancer (contralateral lymph nodes) and in either the supraclavicular or scalene lymph nodes on the same (ipsilateral) or opposite (contralateral) side of the chest as the cancer.

Or

Metastasis in the mediastinal, internal mammary or hilar lymph nodes on the opposite side of the chest as the cancer (contralateral lymph nodes) or in either the supraclavicular or scalene lymph nodes on the same (ipsilateral) or opposite (contralateral) side of the chest as the cancer.

  • Supraclavicular lymph nodes are located above the collarbone (clavicle).
  • Scalene lymph nodes are located at the base of the neck.

Note: The regional lymph nodes are the intrathoracic (within the thorax or chest), internal mammary, scalene and supraclavicular nodes. These lymph nodes are located in the chest and lower part of the neck.

Distant metastasis (M)

M0

No distant metastasis

M1

Distant metastasis

Stage grouping for pleural mesothelioma

The UICC further groups the TNM data into the stages listed in the table below.

UICC staging – pleural mesothelioma
UICC stageTNMExplanation

stage IA

T1a

N0

M0

Mesothelioma in the pleural layer that lines the chest wall on one side of the chest (ipsilateral parietal pleura). It does not involve the pleural lining that covers the lung (visceral pleura).

It has not spread to lymph nodes or distant organs.

stage IB

T1b

N0

M0

Mesothelioma in the parietal pleura with small (focal) tumours on the visceral pleura on one side of the chest.

It has not spread to lymph nodes or distant organs.

stage II

T2

N0

M0

Mesothelioma in any of the pleural surfaces (parietal pleura, pleura lining the mediastinum or diaphragm, and visceral pleura) on one side of the chest. It has also grown into at least one of the following:

  • the visceral pleura that covers the fissures of the lung (fissures divide the lobes of the lungs)
  • the diaphragm
  • the lung itself

It has not spread to lymph nodes or distant organs.

stage III

T1, T2

N1

M0

Mesothelioma in the parietal pleura, the visceral pleural, or both, on one side of the chest. It may or may not have grown into at least one of the following:

  • the diaphragm
  • the lung itself

It has spread to the lymph nodes on the same side of the chest as the mesothelioma. These lymph nodes that contain cancer may be:

  • within the lung (bronchopulmonary lymph nodes)
  • or near where the bronchus enters the lung (hilar lymph nodes)
  • in both locations

It has not spread to distant organs.

T1, T2

N2

M0

Mesothelioma in the parietal pleura, the visceral pleural, or both, on one side of the chest. It may or may not have grown into at least one of the following:

  • the diaphragm
  • the lung itself

It has spread to the lymph nodes on the same side of the chest as the mesothelioma. The lymph nodes that contain cancer may be:

  • below the windpipe (subcarinal lymph nodes)
  • or near the breastbone (internal mammary lymph nodes)
  • or in the centre of the chest between the lungs (mediastinal lymph nodes)
  • in the subcarinal lymph nodes and internal mammary lymph nodes or mediastinal lymph nodes

It has not spread to distant organs.

T3

N0, N1, N2

M0

Mesothelioma involves any of the pleura on one side of the chest and has grown into at least one of the following:

  • the first layer of the chest wall (endothoracic fascia)
  • the fatty part of the mediastinum (the space in the chest between the lungs)
  • a single area of soft tissue of the chest wall, such as muscle or fat
  • the outer surface of the sac that surrounds the heart (pericardium)

It may or may not have spread to lymph nodes closest to the lung, windpipe, breastbone or mediastinum on the same side of the chest as the mesothelioma.

It has not spread to distant organs.

stage IV

T4

any N

M0

Mesothelioma involves any of the pleura on one side of the chest and has grown into at least one of the following:

  • several areas of soft tissue of the chest wall
  • rib
  • the diaphragm and into the peritoneum
  • any organ in the space in the chest between the lungs (mediastinum)
  • the pleura on the opposite side of the chest (contralateral pleura)
  • the spine
  • the inner surface of the sac that surrounds the heart (pericardium)
  • the pericardial fluid – there is an abnormal buildup of fluid in the sac surrounding the heart (pericardial effusion) and the fluid contains cancer cells
  • the middle muscle layer of the heart (myocardium)
  • the network of nerves that run from the spinal cord into the neck and armpit (axilla) which controls muscles in the hand, arm and shoulder (brachial plexus)

It may or may not have spread to lymph nodes. It has not spread to distant organs.

any T

N3

M0

Mesothelioma is any size and may or may not have grown into nearby tissues or organs.

It has spread to lymph nodes in one of the following locations:

  • within the chest (mediastinal, internal mammary or hilar) on the opposite side of the chest as the mesothelioma
  • above the collarbone (supraclavicular) or base of the neck (scalene) on the same or opposite side as the mesothelioma
  • mediastinal, internal mammary or hilar lymph nodes on the opposite side of the chest as the mesothelioma and to supraclavicular or scalene lymph nodes on the same or opposite side as the mesothelioma

It has not spread to distant organs.

any T

any N

M1

Mesothelioma is any size and may or may not have grown into nearby tissues or organs.

It may or may not have spread to the lymph nodes.

It has spread to distant organs.

Recurrent mesothelioma

Recurrent mesothelioma means that the cancer has come back after it has been treated. It may recur in the same location as the original cancer or it may recur in another part of the body (metastatic mesothelioma).

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