Small Cell Lung Cancer Staging 

Updated: Jan 28, 2018
  • Author: Marvaretta M Stevenson, MD; Chief Editor: Nagla Abdel Karim, MD, PhD  more...
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TNM Classification for Small Cell Lung Cancer

The American Joint Committee on Cancer (AJCC) tumor/node/metastasis (TNM) classification, anatomic stages, and prognostic groups for small cell lung cancer are provided below. [1]

See Small Cell Lung Cancer: Beating the Spread, a Critical Images slideshow, to help identify the key clinical and biologic characteristics of small cell lung cancer, the staging criteria, and the common sites of spread.

Also, see Clinical Presentations of Lung Cancer: Slideshow to help efficiently distinguish lung carcinomas from other lung lesions, as well as how to stage and treat them.

Table 1. TNM Classification for Small Cell Lung Cancer (Open Table in a new window)

Primary tumor (T)

TX

Primary tumor cannot be assessed, or tumor is 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

Squamous cell carcinoma in situ (SCIS)

Adenocarcinoma in situ (AIS):  adenocarcinoma with pure lepidic pattern, ≤ 3 cm in greatest dimension

T1

Tumor ≤ 3 cm 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)

T1mi Minimally invasive adenocarcinoma: adenocarcinoma (≤ 3 cm in greatest dimension) with a predominantly lepidic pattern and ≤ 5 mm invasion in greatest dimension

T1a

Tumor ≤ 1 cm in greatest dimension.  A superficial, spreading tumor of any size whose invasive component is limited to the bronchial wall and may extend proximal to the main bronchus also is classified as T1a, but those tumors are uncommon. 

T1b

Tumor > 1 cm but ≤ 2 cm in greatest dimension

T1c Tumor > 2 cm but ≤ 3 cm in greatest dimension

T2

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

  • Involves the main bronchus regardless of distance to the carina, but without involvement of the carina

  • Invades visceral pleura (PL1 or PL2)

  • Associated with atelectasis or obstructive pneumonitis extending to the hilar region, involving part or all of the lung

T2 tumors with these features are classified as T2a if ≤ 4 cm or if the size cannot be determined and T2b if > 4 cm but ≤ 5 cm

T2a

Tumor > 3 cm but ≤ 4 cm in greatest dimension

T2b

Tumor > 4 cm but ≤ 5 cm in greatest dimension

T3

Tumor > 5 cm but ≤ 7 cm in greatest dimension or directly invading any of the following:  parietal pleural (PL3), chest wall (including superior sulcus tumors), phrenic nerve, parietal pericardium; or separate tumor nodule(s) in the same lobe as the primary

T4

Tumor > 7 cm or tumor of any size that invades one or more of the following:  diaphragm, mediastinum, heart, reat vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, or carina; or separate tumor nodule(s) in an ipsilateral lobe different from that of the primary

Regional lymph nodes (N)

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 involvement by direct extension

N2

Metastasis in ipsilateral mediastinal and/or subcarinal lymph node(s)

N3

Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph node(s)

Distant metastasis (M)

M0

No distant metastasis

M1

Distant metastasis

M1a Separate tumor nodule(s) in a contralateral lobe tumor; tumor with pleural or pericardial nodules or malignant pleural or pericardial effusion.  Most pleural (pericardial) effusion with lung cancer are a result of the tumor.  In a few patients, however, multiple miscroscopic examinations of pleural (pericardial) fluid are negative for tumor, and the fluid is nonbloody and not an exudate.  If these elements and clinical judgment dictate that the effusion is not related to the tumor, the effusion should be excluded as a staging descriptor.

M1b

Single extrathoracic metastasis in a single organ and involvement of a single nonregional node

M1c

Multiple extrathoracic metastases in a single organ or in multiple organs

Table 2. Anatomic stage/prognostic groups (Open Table in a new window)

Stage

T

N

M

Limited disease

0

Tis

N0

M0

IA1

T1mi

N0

M0

T1a

N0

M0

IA2 T1b N0 M0
IA3 T1c N0 M0

IB

T2a

N0

M0

IIA T2b N0 M0

IIB

T1a

N1

M0

T1b

N1

M0

T1c

N1 M0
T2a N1 M0
T2b N1 M0

T3

N0

M0

IIIA

T1a

N2

M0

T1b

N2

M0

T1c N2 M0
T2a N2 M0
T2b N2 M0
T3 N1 M0
T4 N0 M0
T4 N1 M0

IIIB

T1a

N3

M0

T1b

N3

M0

T1c

N3

M0

T2a

N3

M0

T2b

N3

M0

T3

N2

M0

T4 N2 M0

IIIC

T3

N3

M0

T4

N3

M0

Extensive disease

IVA T Any N Any M1a
  T Any N Any M1b
IVB T Any N Any M1c

Notes:

  • Limited disease: Confined to the ipsilateral hemithorax, which can be safely encompassed within a tolerable radiation field (T any, N any, M0; except T3-T4 due to multiple lung nodules that do not fit in a tolerable radiation field)

  • Extensive disease: Beyond ipsilateral hemithorax, which may include malignant pleural or pericardial effusion or hematogenous metastases (T any, N any, M1a/b/c; T3-T4 due to multiple lung nodules that do not fit in a tolerable radiation field)