# Radiation Oncology/Mesothelioma/Staging

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Mesothelioma Staging
    (Applies only to Pleural Mesothelioma. Peritoneal and pericardial mesotheliomas are excluded.)
AJCC 7th Edition (2009)
Primary Tumor:
* T1a - involves ipsilateral parietal pleura, no involvement of visceral pleura.
* T1b - involves ipsilateral parietal pleura with involvement of visceral pleura.
* T2 - involves each of the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura) with at least one of the following: 1) involvement of diaphragmatic muscle, or 2) extension of tumor from visceral pleura into underlying pulmonary parenchyma
* T3 - Locally advanced but potentially resectable. Tumor involving all of the ipsilateral pleural surfaces with at least one of the following: 1) invasion of the endothoracic fascia, 2) invasion into mediastinal fat, 3) solitary, completely resectable focus of tumor invading the soft tissues of the chest wall, 4) non-transmural involvement of the pericardium
* T4 - Locally advanced technically unresectable. Tumor involving all of the ipsilateral pleural surfaces with at least one of the following: 1) diffuse or multifocal masses of tumor in the chest wall (with or without rib destruction), 2) invasion through diaphragm to the peritoneum, 3) direct extension to the contralateral pleura, 4) extension to mediastinal organs, 5) invasion into the spine, or 6) extending through to the internal surface of the pericardium (with or without a pericardial effusion or tumor involving the myometrium)
Regional Lymph Nodes:
* N0 - none
* N1 - ipsilateral bronchopulmonary or hilar lymph nodes
* N2 - subcarinal or ipsilateral mediastinal lymph nodes (including ipsilateral internal mammary and peridiaphragmatic nodes)
* N3 - contralateral mediastinal, contralateral internal mammary, ipsilateral or contralateral supraclavicular nodes
Distant Metastases:
* M0 - no
* M1 - yes
Overall stage:
* IA - T1a N0
* IB - T1b N0
* II - T2 N0
* III - T1-2 N1-2, T3 N0-2
* IV - T4, N3, or M1
Changes from AJCC 6th Edition:
* Subtle rewording of some T-stage descriptors
* Peridiaphragmatic lymph nodes added to N2

## Older staging editions

AJCC 6th Edition (2002)
Primary Tumor:
* T1a - involves ipsilateral parietal pleura, no involvement of visceral pleura.
* T1b - involves ipsilateral parietal pleura, focal involvement of visceral pleura.
* T2 - involves ipsilateral pleural surfaces with at least one of the following: 1) confluent visceral pleural tumor, 2) invasion of diaphragmatic muscle, or 3) invasion of lung parenchyma
* T3 - involves any of ipsilateral pleural surfaces with at least one of the following: 1) invasion of the endothoracic fascia, 2) invasion into mediastinal fat, 3) solitary focus of tumor invading the soft tissues of the chest wall, 4) non-transmural involvement of the pericardium
* T4 - involves any of ipsilateral pleural surfaces with at least one of the following: 1) diffuse or multifocal invasion of soft tissues of the chest wall, 2) any rib involvement, 3) invasion through diaphragm to the peritoneum, 4) invasion or any mediastinal organs, 5) direct extension to the contralateral pleura, 5) invasion into the spine, 6) extension to the internal surface of the pericardium, 7) pericardial effusion with positive cytology, 8) invasion of the myocardium, 9) invasion of the brachial plexus
Regional Lymph Nodes:
* N0 - none
* N1 - ipsilateral bronchopulmonary and/or hilar lymph nodes
* N2 - subcarinal, and/or ipsilateral internal mammary or mediastinal lymph nodes
* N3 - contralateral mediastinal, internal mammary, or hilar lymph nodes, and/or ipsilateral or contralateral supraclavicular or scalene lymph nodes
Distant Metastases:
* M0 - no
* M1 - yes
Overall stage:
* IA - T1a N0
* IB - T1b N0
* II - T2 N0
* III - T1-2 N1-2, T3 N0-2
* IV - T4, N3, M1