T — primary tumour
T1mi — minimally invasive adenocarcinoma (≤ 3 cm, invasion ≤ 5 mm)
T2a — > 3 to ≤ 4 cm, or main bronchus / visceral pleura / partial atelectasis
T3 — > 5 to ≤ 7 cm, or chest wall / pericardium / phrenic nerve, or a separate nodule in the same lobe
T4 — > 7 cm, or mediastinum / diaphragm / heart / great vessels / carina / recurrent laryngeal nerve / oesophagus / vertebra, or a separate nodule in a different ipsilateral lobe
N — regional lymph nodes
N0 — no regional lymph node metastasis
N1 — ipsilateral peribronchial and/or hilar nodes
N2 — ipsilateral mediastinal and/or subcarinal nodes
N3 — contralateral mediastinal/hilar, or any scalene or supraclavicular node
M — distant metastasis
M0 — no distant metastasis
M1a — contralateral lung nodule, or pleural/pericardial nodules or malignant effusion
M1b — single extrathoracic metastasis
M1c — multiple extrathoracic metastases
Evidence
Original publication
Detterbeck FC, Boffa DJ, Kim AW, Tanoue LT. The Eighth Edition Lung Cancer Stage Classification. Summarises the IASLC/AJCC 8th-edition changes: T sub-categorised by 1-cm size increments, new T1a(mi), reassignment of several T3/T4 descriptors, and M1b/M1c for single versus multiple extrathoracic metastases.
Chest, 2017
Guideline
Amin MB, Edge SB, Greene FL, et al., eds. AJCC Cancer Staging Manual, 8th edition. Chicago: Springer; 2017. Stage groups implemented here follow the 8th-edition anatomic table; confirm the assigned stage against the manual.
Last reviewed: 2026-09
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