Table 1. Lung Cancer Staging (TNM System)
| Stage |
Definition (Simplified TNM) |
Key Features |
| Stage 0 (Carcinoma in situ) |
Tis N0 M0 |
Tumor confined to epithelium, no invasion, no nodal disease. |
| Stage IA1 |
T1a (≤1 cm) N0 M0 |
Small tumor ≤1 cm, no nodes/metastasis.
 Peripheral Squamous Cell Carcinoma presenting as a small well circumscribed lung nodule
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|
| Stage IA2 |
T1b (>1–2 cm) N0 M0 |
Tumor >1–2 cm, no nodes/metastasis.
|
| Stage IA3 |
T1c (>2–3 cm) N0 M0 |
Tumor >2–3 cm, no nodes/metastasis. |
| Stage IB |
T2a (>3–4 cm) N0 M0 |
Tumor >3–4 cm OR involves main bronchus ≥2 cm from carina, invades visceral pleura, or causes partial atelectasis. |
| Stage IIA |
T2b (>4–5 cm) N0 M0 |
Tumor >4–5 cm, no nodes. |
| Stage IIB |
T1–2 N1 M0 OR T3 N0 M0 |
Tumor ≤5 cm with ipsilateral peribronchial/hilar LN (N1), OR tumor >5–7 cm (T3) without nodes. |
| Stage IIIA |
T1–2 N2 M0 OR T3 N1–2 M0 OR T4 N0–1 M0 |
Spread to mediastinal/subcarinal LN (N2), or larger/multiple tumors invading local structures but still resectable. |
| Stage IIIB |
T1–2 N3 M0 OR T3–4 N2–3 M0 |
Contralateral mediastinal/hilar or supraclavicular nodes (N3), or extensive local invasion. |
| Stage IIIC |
T3–4 N3 M0 |
Locally advanced with extensive nodal spread, but no metastasis. |
| Stage IVA |
Any T Any N M1a OR M1b |
Metastasis within thorax (pleural/pericardial nodules, malignant effusion), or single extrathoracic metastasis. |
| Stage IVB |
Any T Any N M1c |
Multiple extrathoracic metastases in ≥1 organ. |
References and Links
Revised TNM8 Radiographics
Wiki
Radiopaedia
