Table 1.
American Joint Committee on Cancer (AJCC) 8th edition staging criteria for oral cavity cancer.
| Primary Tumor (T) | |||
| TX | Primary tumor cannot be assessed | ||
| Tis | Carcinoma in situ | ||
| T1 | Tumor ≤ 2 cm and DOI ≤ 5 mm | ||
| T2 | Tumor ≤ 2 cm, DOI > 5 mm and ≤10 mm; or Tumor > 2 cm but ≤4 cm and DOI ≤ 10 mm | ||
| T3 | Tumor > 4 cm; or any tumor with DOI > 10 mm but ≤20 mm | ||
| T4a | Moderately Advanced Local Disease: Tumor invades adjacent structures only (e.g., through cortical bone of the mandible or maxilla, or involves the maxillary sinus or skin of the face); or Extensive tumor with bilateral tongue involvement; and/or DOI > 20 mm |
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| T4b | Very advanced local disease: Tumor invades masticator space, pterygoid plates, or skull base and/or encases the internal carotid artery |
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| Clinical Assessment of Regional Lymph Nodes (cN) | |||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node metastasis | ||
| N1 | Metastasis in a single ipsilateral lymph node, ≤3 cm and ENE− | ||
| N2a | Metastasis in a single ipsilateral node, >3 cm and ≤6 cm and ENE− | ||
| N2b | Metastases in multiple ipsilateral nodes, ≤6 cm and ENE– | ||
| N2c | Metastases in bilateral or contralateral lymph nodes, ≤6 cm and ENE− | ||
| N3a | Metastasis in a lymph node > 6 cm and ENE− | ||
| N3b | Metastasis in any lymph node(s) with ENE+ clinically; or Metastasis in a single ipsilateral node, >3 cm and ENE+; or Metastasis to multiple ipsilateral, contralateral, or bilateral nodes and ENE+ |
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| Pathologic Assessment of Regional Lymph Nodes (pN) | |||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node metastasis | ||
| N1 | Metastasis in a single ipsilateral lymph node, ≤3 cm and ENE− | ||
| N2a | Metastasis in a single ipsilateral node, ≤3 cm and ENE+; or Metastasis in a single ipsilateral node > 3 cm and ≤6 cm and ENE− |
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| N2b | Metastases in multiple ipsilateral nodes, ≤6 cm and ENE– | ||
| N2c | Metastases in bilateral or contralateral lymph nodes, ≤6 cm and ENE− | ||
| N3a | Metastasis in a lymph node > 6 cm and ENE− | ||
| N3b | Metastasis in a single ipsilateral node > 3 cm with ENE+; or Metastasis to multiple ipsilateral, contralateral, or bilateral nodes, any with ENE+; or Metastasis to a single contralateral node of any size and ENE+ |
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| Distant Metastasis (M) | |||
| M0 | No distant metastases | ||
| M1 | Distant metastases | ||
| AJCC Prognostic Stage Groups | |||
| Stage 0 | Tis | N0 | M0 |
| Stage I | T1 | N0 | M0 |
| Stage II | T2 | N0 | M0 |
| Stage III | T3 | N0 | M0 |
| T1–T3 | N1 | M0 | |
| Stage IVa | T4a | N0 | M0 |
| T4a | N1 | M0 | |
| T1–T4a | N2 | M0 | |
| Stage IVb | Any T | N3 | M0 |
| T4b | Any N | M0 | |
| Stage IVc | Any T | Any N | M1 |
Abbreviations: DOI, depth of invasion; ENE, extranodal extension.