Quick Reference Guide to TNM Staging of Head and Neck Cancer and Neck Dissection Classification

T4a Moderately advanced local disease

Tumor invades the skin, mandible, ear canal, and/or facial nerve

T4b Very advanced local disease

Tumor invades the skull base and/or pterygoid plates and/or encases the carotid artery

*Note: Extraparenchymal extension is a clinical macroscopic evidence of invasion of soft tissues. Microscopic evidence alone does not constitute extraparenchymal extension for classification purposes. G. Unknown Primary Cancer of the Head and Neck Unknown primary cancer of the head and neck includes all patients with metastatic squamous cell carcinoma to a cervical lymph node without an identifiable primary tumor within the head and neck or a distant site. Of note, all patients with metastatic nodes that are p16+ or EBV+ are considered T0 lesions of the oropharynx or nasopharynx, respectively, and are not considered unknown primary cancers.

PRIMARY TUMOR (T) TX – No identifiable primary tumor H. Nonmelanoma Skin Cancer of the Head and Neck

Cutaneous cancers of the head and neck include the anatomic subsites of the vermillion lip, external ear, face, scalp, and neck. Of note, basal cell carcinoma is not included in this staging system.

PRIMARY TUMOR (T) TX Primary tumor cannot identified Tis Carcinoma in situ T1

Tumor 2 cm or less in greatest dimension

T2 T3 Tumor more than 2 cm but not more than 4 cm in greatest dimension Tumor more than 4 cm in greatest dimension or minor bone erosion or perineural invasion or deep invasion* T4a Tumor with gross cortical bone/marrow invasion T4b Tumor with skull base invasion and/or skull base foramen involvement *Deep invasion is defined as invasion beyond the subcutaneous fat or >6mm (as measured from the granular layer of adjacent normal epidermis to the base of the tumor); perineural invasion for T3 classification is defined as tumor cells within the nerve sheath of a nerve lying deeper than the dermis or measuring 0.1 mm or larger in caliber, or presenting with clinical or radiographic involvement of named nerves without skull base invasion or transgression.

AcademyU.org 21