Evaluation of the Definitions of “High-Risk” Cutaneous Squamous Cell Carcinoma Using the American Joint Committee on Cancer Staging Criteria and National Comprehensive Cancer Network Guidelines
Table 4
Summary of the AJCC 6th edition, AJCC 7th edition, UICC, and BWH tumor- (T-) stage systems.
T-stage
AJCC 6th
AJCC 7th
UICC
T-stage
BWH
T1
Tumor 2 cm or less in greatest dimension
Tumor <2 cm in greatest dimension with fewer than two “high-risk” features*
Tumor ≤2 cm in largest horizontal size
T1
0 high-risk factors
T2
Tumor more than 2 cm but not more than 5 cm in greatest dimension
Tumor >2 cm in greatest dimension or tumor any size with two or more “high-risk” features*
Tumor >2 cm in largest horizontal size
T2a
1 high-risk factor
T2b
2-3 high risk factors
T3
Tumor more than 5 cm in greatest dimension
Tumor with invasion of orbit, maxilla, mandible, or temporal bones
Deep infiltration (skeleton muscle, cartilage, or bone)
T3
≥4 high risk factors
T4
Tumor invades deep extradermal structures (i.e., cartilage, skeleton muscle, or bone)
Tumor with invasion of skeleton (axial or appendicular) or perineural invasion of skull base
Infiltration of base of skull or vertebra
T4
n/a
AJCC high-risk factors include >2 mm thickness, Clark level ≥IV, perineural invasion, primary site ear, primary site non-hair-bearing lip, or poorly differentiated histology. BWH “high-risk” factors include tumor diameter ≥2 cm, poorly differentiated histology, perineural invasion ≥0.1 mm, or tumor invasion beyond fat (excluding bone invasion which automatically upgrades tumor to BWH stage T3).