Table 2. Malignant pleural mesothelioma staging guidelines.
| TNM stage | Definition |
|---|---|
| T | Primary tumor |
| TX | Primary tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| T1 | Tumor limited to the ipsilateral parietal pleura with or without involvement of: |
| 1. Visceral pleura | |
| 2. Mediastinal pleura | |
| 3. Diaphragmatic pleura | |
| T2 | Tumor involving each of the ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura) with at least one of the following features: |
| 1. Involvement of the diaphragmatic muscle | |
| 2. Extension of tumor from visceral pleura into the underlying pulmonary parenchyma | |
| T3 | Locally advanced but potentially resectable tumor. Tumor involving all ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura), with at least one of the following features: |
| 1. Involvement of the endo-thoracic fascia, | |
| 2. Extension into the mediastinal fat | |
| 3. Solitary, completely resectable focus of tumor extending into the soft tissues of the chest wall | |
| 4. Non-transmural involvement of the pericardium | |
| T4 | Locally advanced technically unresectable tumor. Tumor involving all ipsilateral pleural surfaces (parietal, mediastinal, diaphragmatic, and visceral pleura) with at least one of the following features: |
| 1. Diffuse extension or multifocal masses of tumor in the chest wall, with or without associated rib destruction | |
| 2. Direct trans-diaphragmatic extension of the tumor to the peritoneum | |
| 3. Direct extension of tumor to the contralateral pleura | |
| 4. Direct extension of tumor to mediastinal organs | |
| 5. Direct extension of tumor into the spine | |
| 6. Tumor extending through to the internal surface of the pericardium with or without a pericardial effusion; or tumor involving the myocardium | |
| N | Regional lymph nodes |
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastases |
| N1 | Metastases in the ipsilateral bronchopulmonary, hilar, or mediastinal (including the internal mammary, peri-diaphragmatic, pericardial fat pad, or intercostal) lymph nodes |
| N2 | Metastases in the contralateral mediastinal, ipsilateral, or contralateral supraclavicular lymph nodes |
| M | Distant metastasis |
| M0 | No distant metastasis |
| M1 | Distant metastasis present |
Definitions for T, N, M staging as outlined by the 8th edition of the TNM staging system by the International Association for the Study of Lung Cancer/American Joint Committee on Cancer (AJCC). Used with permission of the American College of Surgeons, Chicago, Illinois. The original source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer International Publishing.