Table 3. Stage criteria in the TNM staging system for NSCLC.
| Primary tumor (T) |
| TX: Primary tumor cannot be assessed, or tumor proven by the presence of malignant cells in sputum or bronchial washings but not visualized by imaging or bronchoscopy |
| T0: No evidence of primary tumor |
| Tis: Carcinoma in situ |
| T1: Tumor ≤3 in greatest dimension. Surrounded by lung or visceral pleura, not more proximal than the lobar bronchus under bronchoscopy |
| T1a: Tumor ≤2 cm in greatest dimension |
| T1b: Tumor >2 cm but ≤3 cm in greatest dimension |
| T2: Tumor >3 cm but ≤7 cm or tumor with any of the following (T2 tumors with these features are classified as T2a if ≤5 cm): Involves main bronchus ≥2 cm distal to the carina; invades visceral pleura; atelectasis/obstructive pneumonia extending to hilum but not involving the entire lung |
| T2a: Tumor >3 cm but ≤5 cm in greatest dimension |
| T2b: Tumor >5 cm but ≤7 cm in greatest dimension |
| T3: Tumor >7 cm in greatest dimension or directly invading chest wall (including pulmonary sulcus tumor), diaphragm, phrenic nerve, mediastinal pleura, or parietal pericardium; or tumor in the main bronchus <2 cm distal to the carina; or atelectasis/obstructive pneumonitis of entire lung; or other metastatic nodules in the same lobe |
| T4: Tumor of any size with invasion of heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, or carina; or other metastatic nodules in a different ipsilateral lobe |
| Regional lymph nodes (N) |
| NX: Regional node metastasis cannot be assessed |
| N0: No regional lymph node metastasis |
| N1: Metastasis in ipsilateral peribronchial and/or perihilar lymph nodes and intrapulmonary nodes, including involvement by direct extension |
| N2: Metastasis in ipsilateral mediastinal and/or subcarinal lymph nodes |
| N3: Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph nodes |
| Distant metastasis (M) |
| MX: Distant metastasis can not be assessed |
| M0: No distant metastasis |
| M1: Distant metastasis |
| M1a: Metastatic nodules in a contralateral lobe; or tumor with pleural nodules or malignant pleural dissemination |
| M1b: Extra-pulmonary distant metastasis |
The changes in the 7th edition are provided in italic form. NSCLC, non-small cell lung cancer; TNM, tumor-node-metastasis.