Management of the Neck for Tongue Cancer

Tumors of the tongue:
- Initially metastasize to levels I and II:
  - Lateral tongue tumors frequently metastasizing directly to level II nodes
- Involvement of level V nodes:
  - In the absence of positive nodes in levels I to IV is rare:
    - However it is not unusual for nodes in level IV to be involved:
      - Hence even in elective neck dissections levels I to IV should be dissected
Like floor of mouth tumors:
- The presence of lingual lymph nodes should be considered and either an in-continuity resection with the neck specimen or clearance of tissue above the mylohyoid conducted
Bilateral neck dissections:
- Should be considered in tumours that extend to or beyond the midline.
The management of the neck in larger primary tumors:
- Is usually straightforward since the neck is accessed for microvascular or pedicled flap reconstruction of the primary site
- Management difficulties arise with smaller tumors amenable to peroral resection and local closure
It has been proposed that the increased incidence of nodal metastasis associated with tongue carcinoma:
- May be due to contraction of tongue muscles promoting entry of cancer cells into the lymphatics
- It is thought that mechanism by which tumor thickness is related to cervical metastasis:
  - Is that thicker tumors have access to wider lymphatics:
    - In which tumor emboli can form more readily
- Although tumors arising on the lateral aspect of the tongue tend to be thicker than those of the ventral aspect of the tongue:
  - This may not manifest as a greater risk of cervical metastasis, since the ‘critical thickness’ for tumors of the floor of mouth is less than other oral sites
Elective neck dissection or elective neck radiotherapy:
- Should be considered for tumors thicker than 3 mm to 4 mm:
  - T2 or greater in dimension and T1 tumors that demonstrate poor histological features:
    - Poor differentiation
    - Double DNA aneuploidy
    - Degree of differentiation at the advancing front
Elective neck dissection:
- Significantly improves loco-regional control:
  - It has been demonstrated that conducting an END reduces regional recurrence from 47% in ‘watch and wait’ patients to 9% if END is conducted
END has been shown by some to improve five-year survival:
- The five-year survival of patients undergoing therapeutic neck dissection following a ‘watch and wait’ policy being 35% as opposed to 69% when an elective neck dissection is conducted
  - Others, however, have not demonstrated a survival advantage