Malignant pleural mesothelioma (TNM staging)

A number of staging systems have been described for staging of malignant pleural mesothelioma. Below is the International Mesothelioma Interest Group TNM staging system.

TNM

T - Tumour

• Tx: primary tumour cannot be assessed
• T0: no evidence of primary tumour
• T1a
  • potentially resectable
  • only parietal pleura
  • no mediastinal pleural involvement
• T1b
  • potentially resectable
  • parietal pleura AND
  • scattered foci of mediastinal pleural involvement
• T2
  • potentially resectable
  • parietal and visceral pleural involvement, and / or
  • pulmonary parenchymal involvement and/or
  • diaphragmatic muscle involvement
• T3
  • potentially resectable
  • localised tumour extension into endothoracic fascia and / or
  • localised non-transmural involvement of pericardium and / or
  • localised extension into mediastinal fat
• T4
  • unresectable
  • multiple foci of extension into chest wall +/- rib destruction and/or
  • extension through diaphragm into peritoneum and / or
  • extension into contralateral pleura and / or
  • extension into mediastinal organs and / or
  • extension through pericardium +/- direct extension into heart

N - Nodes

• Nx: nodes cannot be assessed
• N0: no evidence of nodal involvement
• N1: ipsilateral bronchopulmonary or hilar nodal involvement
• N2: subcarinal or ipsilateral mediastinal / internal mammary nodes
• N3: contralateral mediastinal / internal mammary nodes,or ipsilateral / contralateral supraclavicular nodes

M - Metastases

• Mx: presence of metastases cannot be assessed
• M0: no evidence of metastases
• M1: distant metastases present

Stage groupings

• Stage IA: T1a, N0, M0
• Stage IB:T1b, N0, M0
• Stage II: T2, N0, M0
• Stage III:
  • T1 or 2,  N1 or N2, M0 OR
  • T3, any N, M0
• Stage IV: any T, any N, M1