The International Mesothelioma Interest Group Staging System for malignant pleural mesothelioma

 T1Tumour of the ipsilateral parietal pleura, including diaphragm and mediastinal pleura
 T1aNo visceral pleural involvement
 T1bWith visceral pleural involvement
 T2Tumour affecting parietal, visceral, diaphragmatic and mediastinal pleura, with either involvement of diaphragmatic muscles or pulmonary parenchyma
 T3Involvement of the endothoracic fascia, extension into the mediastinal fat, non-transmural involvement of the pericardium or resectable focus of chest wall invasion
 T4Unresectable disease, diffuse chest wall or mediastinal involvement, direct transdiaphragmatic spread into the peritoneum, contralateral plural involvement, invasion of the spine, ribs or brachial plexus, trans-mural pericardial invasion or malignant pericardial effusion
 N0No regional lymph node metastases
 N1Metastases in ipsilateral bronchopulmonary or hilar lymph nodes
 N2Metastases in subcarinal or ipsilateral mediastinal lymph nodes, including ipsilateral internal mammary chain
 N3Contralateral lymph node metastases, ipsilateral or contralateral supraclavicular lymph node involvement, and scalene nodes
 M0No extrathoracic metastases
 M1Extrathoracic metastases present
  • Reproduced from [41] with permission from the publisher.