2002 American Joint Committee on Cancer (AJCC) TNM Staging System for the Lung

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 cm or less in greatest dimension, surrounded by lung or visceral pleura, without bronchoscopic evidence of invasion more proximal than the lobar bronchus† (ie, not in the main bronchus)
T2: Tumor with any of the following features of size or extent:
  *More than 3 cm in greatest dimension
  *Involves main bronchus, 2 cm or more distal to the carina
  *Invades the visceral pleura
  *Associated with atelectasis or obstructive pneumonitis that extends to the hilar region but does not involve the entire lung
T3; Tumor of any size that directly invades any of the following: chest wall (including superior sulcus tumors), diaphragm, mediastinal pleura, parietal pericardium; or tumor in the main bronchus less than 2 cm distal to the carina, but without involvement of the carina; or associated atelectasis or obstructive pneumonitis of the entire lung
T4: Tumor of any size that invades any of the following: mediastinum, heart, great vessels, trachea, esophagus, vertebral body, carina; or separate tumor nodules in the same lobe; or tumor with a malignant pleural effusion‡

†The uncommon superficial tumor of any size with its invasive component limited to the bronchial wall, which may extend proximal to the main bronchus, is also classified T1. ‡Most pleural effusions associated with lung cancer are due to tumor. However, in a few patients, multiple cytopathologic examinations of pleural are negative for tumor. In these cases, fluid is not bloody and is not an exudate. Such patients may be further evaluated by videothoracoscopy (VATS) and direct pleural biopsies. When these elements and clinical judgment dictate that the effusion is not related to the tumor, the effusion should be excluded a staging element and the patient should be staged T1, T2, or T3. M1 includes separate tumor nodule(s) in a different lobe (ipsilateral or contralateral).

NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis to ipsilateral peribronchial and/or ipsilateral hilar lymph nodes, and intrapulmonary nodes including involvment by direct extension of the primary tumor
N2 Metastasis to ipsilateral mediastinal and/or subcarinal lymph node(s)
N3 Metastasis to contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph node(s)

Stage 0: Carcinoma in situ
Stage IA: T1, N0, M0
Stage IB: T2, N0, M0
Stage IIA: T1, N1, M0
Stage IIB: T2, N1, M0, T3, N0, M0
Stage IIIA: T1, N2, M0, T2, N2, M0, T3, N1, M0, T3, N2, M0
Stage IIIB: T4, N0, M0, T4, N1, M0, T4, N2, M0, T1, N3, M0, T2, N3, M0, T3, N3, M0, T4, N3, M0
Stage IV: Any T, any N, M1