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Non-Small Cell Lung Cancer Treatment (PDQ®)

  • Updated: 02/21/2014

Table 5. Definitions of TNM Stage IBa

Stage TNM Description Illustration 
IBT2a, N0, M0T2a = Tumor >3 cm but ≤5 cm in greatest dimension, or tumor with any of the following features: involves main bronchus, ≥2 cm distal to the carina; invades visceral pleura (PL1 or PL2); or is associated with atelectasis or obstructive pneumonitis that extends to the hilar region but does not involve the entire lung.
N0 = No regional lymph node metastasis.
M0 = No distant metastasis.

aReprinted with permission from AJCC: Lung. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 253-70.
bThe uncommon superficial spreading of the tumor of any size with its invasive component limited to the bronchial wall, which may extend proximally to the main bronchus, is also classified as T1a.