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Non-Small Cell Lung Cancer Treatment (PDQ®)

  • Updated: 02/21/2014

Table 4. Definitions of TNM Stage IAa

Stage TNM Description Illustration 
IAT1a, N0, M0T1a = Tumor ≤2 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).b
N0 = No regional lymph node metastasis.
M0 = No distant metastasis.
T1b, N0, M0T1b = Tumor >2 cm but ≤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).b
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.