SEER Training Modules

Head & Neck Staging: Table One

Lip and Oral Cavity (C00, C02-C06)
TNM Classification Histological/Clinical Features
T1 2 cm or less
T2 > 2 but < 4 cm
T3 > 4 cm
T4(lip) Invades through cortical bone, inferior nerve, floor of mouth, or skin of face, i.e, chin or nose
T4a (Oral cavity) invades adjacent structures (e.g., through cortical bone, into deep [extrinsic] muscle of tongue [genioglossus, hypoglossus, palataglossus, and styloglossus], maxillary sinus, skin of face)
T4b Tumor invades masticator space, pterygoid plates, or skull base and/or encases internal carotid artery

Note: Superficial erosion alone of bone/tooth socket by gingival primary is not sufficient to classify as T4.