Primary Tumor (T)
TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
Tis: "insitu" – cancer contained
T1: Tumor 2 cm or less in size
T2: Tumor > 2 cm but <> 4 cm in size
T4a: Tumor invades structures next to it
T4b: Tumor invades to areas beyond the structures next to it
Regional Lymph Nodes (N)
NX: Regional nodes cannot be assessed or unknown
N0: No regional lymph node metastasis
N1: Metastasis in 1 lymph node on the same side as the tumor, <> 6 cm in size
Distant Metastasis (M)
MX: Distant metastasis cannot be assessed
M0: No distant metastasis
M1: Distant metastasis
Staging
Stage T N M
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T3 N0 M0
T1-3 N1 M0
Stage IVa T4a N0 or N1 M0
T1-4a N2 M0
Stage IVb T4b Any N M0
Any T N3 M0
Stage IVc Any T Any N M1
