Radiation Oncology/NSCLC/Staging

Lung Cancer Staging

AJCC 7th Edition (2009)

• corresponds with IASLC staging - published: PMID 19584208 (Chest 2009 Jul;136(1):260-71.)
• IASLC document (PDF)

Primary Tumor:

• T1 - 3 cm or less, surrounded by lung or visceral pleura, not invading into a main bronchus
  • T1a - tumor 2 cm or less
  • T1b - > 2 cm but <= 3 cm
• T2 - tumor >3 cm but <= 7 cm; or tumor with any of the following: involves main bronchus (2cm or more distal to the carina), invades visceral pleura; associated with atelectasis or obstructive pneumonitis that extends to the hilar region but does not involve the entire lung
  • T2a - >3 cm but <= 5 cm (also includes T2 tumors smaller than 3 cm)
  • T2b - >5 cm but <= 7 cm
• T3 - tumor > 7 cm; or tumor that directly invades one of the following: parietal pleura, chest wall, diaphragm, phrenic nerve, mediastinal pleura, parietal pericardium; or tumor in the main bronchus less than 2 cm distal to the carina; or associated atelectasis or obstructive pneumonitis of the entire lung; or separate tumor nodules in the same lobe
• T4 - tumor invades: mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, carina; or separate tumor nodule(s) in a different ipsilateral lobe

Regional Lymph Nodes:

• N0 - no nodes
• N1 - ipsilateral peribronchial and/or ipsilateral hilar lymph nodes or intrapulmonary nodes
• N2 - ipsilateral mediastinal and/or subcarinal nodes
• N3 - contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene or supraclavicular nodes

Distant Metastases:

• M0 - none
• M1
  • M1a - separate tumor nodule(s) in a contralateral lobe; tumor with pleural nodules or malignant pleural or pericardial effusion
  • M1b - distant metastases

Stage Grouping:

• IA - T1(a or b) N0
• IB - T2a N0
• IIA - T1(a or b) N1, T2a N1, T2b N0
• IIB - T2b N1, T3 N0
• IIIA - T3 N1, T1-3 N2, T4 N0-1
• IIIB - N3 any, T4 N2-3
• IV - M1a or M1b

Changes from AJCC 6th Edition:
Changes in TNM:

• Size: New size classifications (<2, 2-3, 3-5, 5-7, >7). Subclassifications of T1a/b and T2a/b. New size classification separating T2 and T3.
• Separate tumor nodules: (same lobe) now T3 instead of T4. (different ipsilateral lobe) T4 instead of M1. (contralateral lobe) M1a
• Subdivision of M1 into M1a (pleural effusion, tumor nodules in contralateral lobe) and M1b (distant mets)
• some old T2 tumors (>7cm) now classified as T3
• N-stage: no change

Stage grouping changes:

• T2aN1 downstaged to IIA (instead of IIB for old T2N1)
• T2bN0 upstaged to IIA (instead of IB for old T2N0)
• T4N0-N1 downstaged to IIIA (instead of IIIB)
• pleural effusion is now Stage IV (M1a) instead of IIIB (T4)
• separate nodule in same lobe is now T3 (IIB,IIIA,or IIIB) instead of T4(IIIB)
• ipsilateral lung nodule (different lobe) is now T4 (IIIA or IIIB) instead of Stage IV

Comparison chart:

Old TNM	New 7th ed	N0	N1	N2	N3
T1 (<= 2 cm)	T1a	IA	IIA	IIIA	IIIB
T1 (2-3 cm)	T1b	IA	IIA	IIIA	IIIB
T2 (<5 cm)	T2a	IB	IIA	IIIA	IIIB
T2 (5-7cm)	T2b	IIA	IIB	IIIA	IIIB
T2 (>7 cm)	T3	IIB	IIIA	IIIA	IIIB
T3 invasion
same lobe nodules
T4 invasion	T4	IIIA	IIIA	IIIB	IIIB
ipsilateral lung nodules
pleural effusion	M1a	IV	IV	IV	IV
distant mets	M1b
Table adapted from IASLC

Note:

• The 7th Edition recommended that AJCC staging be applied to Small Cell Lung Cancer and Pulmonary Carcinoid Tumors

Older staging editions

AJCC 6th Edition (2002)

Primary Tumor:

• T1 - 3 cm or less, surrounded by lung or visceral pleura, not invading into a main bronchus
• T2 - Any of the following: 1) more than 3 cm, 2) involves main bronchus, 2 cm or more distal to the carina, 3) invades the visceral pleura, 4) 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 invades any of the following: 1) chest wall, 2) diaphragm, 3) mediastinal pleura, 4) parietal pericardium; or 5) tumor in the main bronchus less than 2 cm distal to the carina but without involvement of the carina; or 6) associated atelectasis or obstructive pneumonitis of the entire lung
• T4 - Tumor of any size that invades any of the following:
  • 1) mediastinum, 2) heart, 3) great vessels, 4) trachea, 5) esophagus, 6) vertebral body, or 7) carina;
  • 8) separate tumor nodules in the same lobe;
  • 9) malignant pleural effusion

Regional Lymph Nodes:

• N0 - no nodes
• N1 - ipsilateral peribronchial and/or ipsilateral hilar lymph nodes or intrapulmonary nodes
• N2 - ipsilateral mediastinal and/or subcarinal nodes
• N3 - contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene or supraclavicular nodes

Distant Metastases:

• M0 - no
• M1 - yes
  • includes separate tumor nodules in a different lobe (ipsilateral or contralateral)

Stage Grouping:

• IA - T1 N0
• IB - T2 N0
• IIA - T1 N1
• IIB - T2 N1, T3 N0
• IIIA - T3 N1, T1-3 N2
• IIIB - N3 or T4
  • T4 N0-1 (invasive but potentially resectable; includes upstaged to T4 due to satellite lesions)
  • T4 N0-1 (upstaged to T4 because of pleural/pericardial effusion; unresectable)
  • T4 N2-3 (invasive and mediastinal+ LNs; unresectable)
  • T1-3 N3 (possibly smaller but contralateral LNs; unresectable)
• IV - M1

NOTE: the 1997 AJCC Staging System moved T3,N0 from Stage III to IIB, complicating the interpretation of older trials of Stage III patients which would have had better prognosis.