Lung cancer (staging - IASLC 8th edition)

The IASLC (International Association for the Study of Lung Cancer) 8^th edition lung cancer staging system was introduced in 2016 and supercedessupersedes the IASLC 7^th edition. 

It is as follows:

TNM system

T: primary tumour

• Tx: primary tumour cannot be assessed or tumour proven by presence of malignant cells in sputum or bronchial washings but not visualised by imaging or bronchoscopy
• T0: no evidence of primary tumour
• Tis: carcinoma in situ
• T1: tumour under 3 cm in greatest dimension surrounded by lung or visceral pleura without bronchoscopic evidence of invasion more proximal than the lobar bronchus (i.e. not in the main bronchus)
  • T1a(mi): minimally invasive adenocarcinoma
  • T1a ss: superficial spreading tumor in central airways (sprerading tumor of any size but confined to the tracheal or bronchial wall)
  • T1a: tumour <1≤1 cm in greatest dimension
  • T1b: tumour >1 cm but <2≤2 cm in greatest dimension
  • T1c: tumour >2 cm but <3≤3 cm in greatest dimension
• T2: tumour >3 cm but <5≤5 cm or tumour with any of the following features:
  • involves main bronchus regardless of distance from the carina but without involvement of the carina
  • invades visceral pleura
  • associated with atelectasis or obstructive pneumonitis that extends to the hilar region,
  • involving part or all of the lung
  • T2a: tumour >3 cm but <4≤4 cm in greatest dimension
  • T2b: tumour >4 cm but <5≤5 cm in greatest dimension
• T3: tumour >5 cm but <7≤7 cm in greatest dimension or associated with separate tumour nodule(s) in the same lobe as the primary tumour or directly invades any of the following structures:
  • chest wall (including the parietal pleura and superior sulcus)
  • phrenic nerve
  • parietal pericardium
• T4: tumour >7 cm in greatest dimension or associated with separate tumour nodule(s) in a different ipsilateral lobe than that of the primary tumour or invades any of the following structures
  • diaphragm
  • mediastinum
  • heart
  • great vessels
  • trachea
  • recurrent laryngeal nerve
  • oesophagus
  • vertebral body
  • carina

N: regional lymph node involvement

• Nx: regional lymph nodes cannot be assessed
• N0: no regional lymph node metastasis
• N1: metastasis in 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)

M: distant metastasesmetastasis

• M0: no distant metastasis
• M1: distant metastasis present
  • M1a: separate tumour nodule(s) in a contralateral lobe; tumour with pleural or pericardial nodule(s) or malignant pleural or pericardial effusions
  • M1b: single extrathoracic metastasis
  • M1c: multiple extrathoracic metastases in one or more organs

Stage groupings

• stage 0
  • TNM equivalent: T_is, N0 ,M0
• stage Ia
  • TNM equivalent: T1 , N0, M0
  • 5-year survival: up to 92%
• stage Ib
  • TNM equivalent: T2a, N0, M0
  • 5-year survival: 68%
• stage IIa
  • TNM equivalent: T2b, N0, M0
  • 5-year survival: 60%
• stage IIb
  • TNM equivalent: T1/T2, N1, M0 or T3, N0, M0
  • 5-year survival: 53%
• stage IIIa
  • TNM equivalent: T1/T2, N2, M0 or T3/T4, N1, M0 or T4, N0, M0
  • 5-year survival: 36%
• stage IIIb
  • TNM equivalent: T1/T2 , N3, M0 or T3/T4, N2, M0
  • 5-year survival: 26%
• stage IIIc
  • TNM equivalent: T3/T4, N3, M0
  • 5-year survival: 13%
• stage IVa
  • TNM equivalent: any T, any N with M1a/M1b
  • 5-year survival: 10%
• stage IVb
  • TNM equivalent: any T, any N with M1c
  • 5-year survival: 0%