TNM Staging Guide 5th Edition eBook

II. American Joint Committee on Cancer (AJCC) Tumor Staging by Site

A. Oral Cavity The anterior border is the junction of the skin and vermilion border of the lip. The posterior border is formed by the junction of the hard and soft palates superiorly, the circumvallate papillae inferiorly, and the anterior tonsillar pillars laterally. The various sites within the oral cavity include the lip, gingival, hard palate, buccal mucosa, floor of mouth, anterior two-thirds of tongue, and retromolar trigone. Recent data has shown that primary tumor depth of invasion (DOI) has a significant impact on disease outcomes and compliments the previous criteria used for T-stage classification. As a result, the new staging system incorporated DOI to reflect this influence on prognosis. PRIMARY TUMOR (T) TX Primary tumor cannot be assessed T0 No evidence of primary tumor Tis Carcinoma in situ T1 Tumor ≤ 2 cm with depth of invasion (DOI)* ≤ 5 mm T2 Tumor ≤ 2 cm with DOI* > 5 mm or tumor > 2 cm and ≤ 4 cm with DOI* ≤ 10 mm T3 Tumor > 2 cm and ≤ 4 cmwith DOI* > 10mm or tumor > 4 cmwith DOI ≤ 10mm T4a Moderately advanced local disease Tumor > 4 cm with DOI* > 10 mm or tumor invades adjacent struc- tures only (e.g., through cortical bone of the mandible or maxilla or involves the maxillary sinus or skin of the face) Note: Superficial erosion of bone/tooth socket (alone) by a gingival primary is not sufficient to classify a tumor as T4.

T4b Very advanced local disease

Tumor invades masticator space, pterygoid plates, or skull base and/ or encases internal carotid artery

*DOI is depth of invasion and not tumor thickness. *Note: Superficial erosion alone of bone/tooth socket by gingival primary is not sufficient to classify as T4.

14 TNM Staging of Head and Neck Cancer and Neck Dissection Classification