Table 1.

AJCC staging system for cutaneous squamous cell carcinoma.

AJCC tumor staging system for cSCC
T classification
Tx	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ
T1	Tumor ≤2 cm in greatest dimension with <2 high-risk features
T2	Tumor >2 cm in greatest dimension or any size with ≥2 high-risk features
T3	Tumor with invasion of maxilla, mandible, orbit, or temporal bone
T4	Tumor with invasion of skeleton (axial or appendicular) or perineural invasion of skull base
N classification
Nx	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1	Metastasis in a single ipsilateral lymph node, ≤3 cm
N2	Metastasis in a single ipsilateral lymph node, >3 cm but ≤6 cm in greatest dimension; or in bilateral or contralateral lymph nodes, none greater than 6 cm
N2a	Metastasis in a single ipsilateral lymph node >3 cm but ≤6 cm
N2b	Metastasis in multiple ipsilateral lymph nodes, none >6 cm
N2c	Metastasis in bilateral or contralateral lymph nodes, none >6 cm
N3	Metastasis in a lymph node >6 cm in greatest dimension