Table 2.
Incidences of T staging criteria and the relationships among them, n (%)
| Staging criteria | Cases | Accompanied by equivalent/higher T stage criteria | Not accompanied by equivalent/higher T stage criteria | |
|---|---|---|---|---|
| T1 | Nasopharynx | 325 (100) | 283 (87.1) | 42 (12.9) |
| Oropharynx | 32 (9.8) | 32 (100) | 0 | |
| Nasal cavity | 61 (18.8) | 61 (100) | 0 | |
| T2 | Parapharyngeal space | 283 (87.1) | 209 (73.9) | 74 (26.1) |
| Medial pterygoid muscle | 176 (54.2) | 176 (100) | 0 | |
| Lateral pterygoid muscle | 51 (15.7) | 51 (100) | 0 | |
| Prevertebral muscle | 92 (28.3) | 92 (100) | 0 | |
| T3 | Bony structures at the skull base | 131 (40.3) | 96(73.3) | 35 (26.7) |
| Cervical vertebra | 13 (4.0) | 13 (100) | 0 | |
| Pterygoid structures | 49 (15.1) | 45 (98.8) | 4 (1.2) | |
| Paranasal sinuses | 89 (27.4) | 89 (100) | 0 | |
| T4 | Intracranial | 35 (10.8) | 23 (65.7) | 12 (34.3) |
| Cranial nerves | 24 (7.4) | 20 (83.3) | 4 (16.7) | |
| Hypopharynx | 3 (0.9) | 3 (100) | 0 | |
| Orbit | 10 (3.1) | 10 (100) | 0 | |
| Parotid gland | 21 (6.5) | 12 (57.1) | 9 (42.9) | |
| Soft tissue infiltration beyond the lateral surface of the lateral pterygoid muscle | 14 (4.3) | 11 (78.6) | 3 (21.4) |