International Staging System for Lung Cancer

Primary tumor (T)

Tis

Carcinoma in situ

T1

Tumor ≤ 3 cm without invasion more proximal than the lobar bronchus

T1mi

Minimally invasive adenocarcinoma

T1a

Tumor ≤ 1 cm

T1b

Tumor > 1 cm but ≤ 2 cm

T1c

Tumor > 2 cm but ≤ 3 cm

T2

Tumor > 3 cm but ≤ 5 cm or with any of the following:

• Involves the main bronchus ≥ 2 cm distal to carina

• Invades the visceral pleura

• Associated with atelectasis or obstructive pneumonia that extends to the hilar region but, involving part of the lung or the entire lung

T2a

Tumor > 3 but ≤ 4 cm

T2b

Tumor > 4 but ≤ 5 cm

T3

Tumor > 5 cm but ≤ 7 cm or with any of the following:

• Invades the chest wall (including superior sulcus tumors), phrenic nerve, parietal pericardium

• Separate tumor nodules in the same lobe

T4

Tumor > 7 cm or with either of the following:

• Invades the diaphragm, mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, or carina

• ≥ 1 Satellite tumors in a different ipsilateral lobe

Regional lymph nodes (N)

N0

No regional lymph node metastasis

N1

Metastasis to ipsilateral peribronchial or ipsilateral hilar lymph node or both and to intrapulmonary nodes, including that by direct extension of the primary tumor

N2

Metastasis to ipsilateral mediastinal or subcarinal lymph node or both

N3

Metastasis to contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph node or a combination

Distant metastasis (M)

M0

No distant metastasis

M1

Distant metastasis

M1a

Tumor with any of the following:

• ≥ 1 Tumor nodules in the contralateral lung

• Pleural or pericardial nodules

• Malignant pleural or pericardial effusion

M1b

Single extrathoracic metastasis in a single organ

M1c

Multiple extrathoracic metastases in one or several organs

Stage groupings

• Stage 0: Tis N0 M0

• Stage IA1: T1mi–T1a N0 M0

• Stage IA2: T1b N0 M0

• Stage IA3: T1c N0 M0

• Stage IB: T2a N0 M0

• Stage IIA: T2a N0 M0

• Stage IIB: T1a-T2b N1 M0 or T3 N0 M0

• Stage IIIA: T1a–T2b N2 M0 or T3 N M0 or T4 N0–N1 M0

• Stage IIIB: T1a–T2b N3 M0 or T3-T4 N2 M0

• Stage IVA: T (any) N (any) M1a–M1b

• Stage IVB: T (any) N (any) M1c