Table 1.

Tumor staging of oral cavity squamous cell carcinoma per AJCC8 guidelines.

T-Classification	Tumor Size and Depth of Invasion (DOI)
T1	≤ 2 cm and DOI ≤ 5 mm
T2	≤ 2 cm and 5 < DOI ≤ 10 mm OR >2 and ≤ 4 cm and DOI ≤ 10 mm
T3	>2 and ≤ 4 cm and DOI > 10 mm OR > 4 cm and 0 < DOI ≤ 10mm
T4a	> 4 cm and DOI > 10 mm OR Moderately Advanced Local Disease *
T4b	Very Advanced Local Disease *

Abbreviations: American Joint Committee on Cancer (AJCC); depth of invasion (DOI). * Moderately advanced—invasion of local structures including mandibular/maxillary cortical bone, maxillary sinus, or skin of face; Very advanced—invasion into masticator space, pterygoid plates, or skull base and/or encasement of internal carotid artery.