Oral cancer is separated into lateral tumors and midline tumors.
- Lateral tumors – bucca, gingiva and retromolar space with a minimum of 1 cm distance to the midline without spreading to contralateral lymph nodes.
- Midline tumors – tongue, floor of the mouth and hard palate. Tumors growing toward the midline have a tendency for bilateral lymph node spreading.
Epithelial tumors are classified according to the Union for International Cancer Control (UICC) (3,4).
The T classification represents the extent of the primary tumor.
- T1 – small tumors ≤ 2 cm of greatest diameter
- T2 – tumors 2–4 cm of greatest diameter
- T3 – Tumors > 4 cm, < 6 cm
- T4 – Advanced tumors with invasion of neigboring organs, muscle, bone, and skin (2).
The N classification represents spreading to regional cervical lymph nodes measured in greatest diameter.
- N0 – no regional lymph node metastases
- N1 – single ipsilateral lymph node metastasis ≤ 3 cm
- a – single ipsilateral lymph node metastasis > 3 cm ≤ 6 cm
- b – multiple ipsilateral lymph node metastases ≤ 6 cm
- c – bilateral or contralateral lymph node metastases ≤ 6 cm
- N3 – lymph node metastases > 6 cm
The M classification represents distant metastases.
- M0 – no distant metastases
- M1 – distant metastases