Table 1. Primary Tumor (T)a
| TX | Primary tumor cannot be assessed. |
| T0 | No evidence of primary tumor. |
| Tis | Carcinoma in situ. |
| T1 | Tumor ≤2 cm in greatest dimension. |
| T2 | Tumor >2 cm but ≤4 cm in greatest dimension. |
| T3 | Tumor >4 cm in greatest dimension or extension to lingual surface of epiglottis. |
| T4a | Moderately advanced local disease. Tumor invades the larynx, extrinsic muscle of tongue, medial pterygoid, hard palate, or mandible.b |
| T4b | Very advanced local disease. Tumor invades lateral pterygoid muscle, pterygoid plates, lateral nasopharynx, or skull base, or encases carotid artery. |
| aReprinted with permission from AJCC: Pharynx. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 41-56. |
| bMucosal extension to lingual surface of epiglottis from primary tumors of the base of the tongue and vallecula does not constitute invasion of larynx. |
