Lung cancer (staging - IASLC 7th edition - superseded)

The IASLC (International Association for the Study of Lung Cancer) 7th edition lung cancer staging system was proposed in 2010 and has now been updated and superseded by the 8th edition, published in 2016.

Small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) used to be staged differently, with this staging system initially proposed only for NSCLC. This has changed since 2013, with the IASLC staging now applying for both types of tumor. 

TNM system

The old 7^th edition (2010) staging is as follows ⁴:

Primary tumor (T)

The parameters assessed on the T stage include size, endobronchial location, local invasion, atelectasis, and separate tumor nodules.

• Tx: malignant cells on cytology but no tumor found on bronchoscopy or imaging.
• Tis: carcinoma in situ
• T1
  • tumor size equal or less than 3 cm 
  • not involving the main bronchus
    • T1a: smaller than 2 cm in longest dimension 
    • T1b: larger than 2 cm but smaller or equal to 3 cm 
• T2: 
  • tumor size more than 3 cm but less/equal to 7 cm or
  • involving the main bronchus but >2 cm from carina
  • visceral pleural involvement
  • lobar atelectasis extending to the hilum but not collapse of the entire lung 
    • T2a: larger than 3 cm but smaller than 5 cm
    • T2b: larger than 5 cm but smaller than 7 cm
• T3
  • tumor size more than 7 cm or 
  • tumor <2 cm from carina but not involving trachea or carina
  • involvement of the chest wall, including Pancoast tumor, diaphragm, phrenic nerve, mediastinal pleura or parietal pericardium
  • separate tumor nodule(s) in the same lobe
  • atelectasis or post-obstructive pneumonitis of the entire lung
• T4
  • any size tumor with:
  • involvement of the trachea, esophagus, recurrent laryngeal nerve, vertebra, great vessels or heart 
  • separate tumor nodules in the same lung but not in the same lobe

Nodal status (N)

• Nx: regional nodes cannot be assessed
• N0: no regional nodal metastases
• N1: ipsilateral peribronchial, hilar or intrapulmonary nodes, including direct invasion
• N2: ipsilateral mediastinal or subcarinal nodes
• N3: contralateral nodal involvement; ipsilateral or contralateral scalene or supraclavicular nodal involvement

Distant metastasis (M)

• Mx: distant metastases cannot be assessed
• M0: no distant metastases
• M1: distant metastases present
  • M1a: presence of a malignant pleural or pericardial effusion, pleural dissemination, or pericardial disease, and metastasis in opposite lung
  • M1b: extrathoracic metastases

AJCC staging system

• stage 0
  • TNM equivalent: carcinoma in situ
  • resectable: yes
• stage I
  • TNM equivalent: T1 or T2, N0, M0
  • resectable: yes
  • 5-year survival: 47%
• stage IIa
  • TNM equivalent: T1, N1, M0
  • resectable: yes
• stage IIb
  • TNM equivalent: T2, N1, M0 or T3, N0, M0
  • resectable: yes
  • 5-year survival: 26%
• stage IIIa
  • TNM equivalent: T1 or 2, N2, M0 or T3, N1 or 2, M0
  • resectable: yes

• stage IIIb
  • TNM equivalent: T1, 2 or 3, N3, M0 or T4, N0, 1, 2 or 3, M0
  • resectable: no
  • 5-year survival: 8%
• stage IV
  • TNM equivalent: any T, any N with M1
  • resectable: no
  • 5-year survival: 2%

Histological grade

• grade 1: well differentiated
• grade 2: moderately differentiated
• grade 3: poorly differentiated
• grade 4: undifferentiated

Proposed lymph node zones

For prognostic purposes, thoracic lymph nodes can be divided into prognostic zones which is easier to remember than individual thoracic lymph node stations/levels ⁶:

• supraclavicular zone: nodal station 1
• upper zone: nodal stations 2-4
• aortopulmonary zone: nodal stations 5-6
• subcarinal and lower zones: nodal stations 7-9
• hilar/interlobar and peripheral zones: nodal stations 10-14

Nodal numbering system

• 1  = low cervical, supraclavicular and sternal notch nodes
• 2 = upper paratracheal nodes 
  • 2R = right upper paratracheal nodes
  • 2L  = left upper paratracheal nodes
• 3  = prevascular and retrotracheal nodes
• 4 = lower paratracheal nodes
  • 4R = right lower paratracheal nodes
  • 4L = left lower paratracheal nodes
• 5  = subaortic/ aortopulmonary nodes 
• 6 = para-aortic nodes
• 7  = subcarinal nodes
• 8 = para-esophageal nodes
• 9  = pulmonary ligament nodes
• 10 = hilar nodes
  • 10R = right hilar nodes
  • 10L = left hilar nodes
• 11 = interlobar nodes
  • 11R = right interlobar nodes
  • 11L = left interlobar nodes
• 12 = lobar nodes
  • 12R = right lobar nodes
  • 12L  = left lobar nodes
• 13 = segmental nodes
  • 13R = right segmental nodes
  • 13L  = left segmental nodes
• 14 = subsegmental nodes
  • 14R = right subsegmental nodes
  • 14L = left subsegmental nodes

See also 

• lung cancer staging IASCL 7^th edition