Clinical applicability
While previous studies have included diffferent approaches to slelective
neck dissection, the little data available has only showed occult
metastases at level 2. As no level V found metastases were found and
given the increased risk of damage to the accessory nerve, this data
does not support inclusion of level V in a selective ND for a cN0 neck.
While some authors have suggested a that frozen section samples are sent
for Level 2 prior to proceeding to dissect other levels in the neck
based on the results, it seems reasonable to perform a supra-omohyoid or
level II and III neck dissection in cN0 necks given that this also
facilitates vessel preparation for a microvascular free flap as is often
required in these cases (23, 24).
Based on our meta-analysis’s findings of an 11% occult risk of TBSCC
cervical metastases, specifically 12% for T3 and 14% for T4 tumours
predominantly confined to level II, we would advocate a selective level
2 and 3 neck dissection in T3 and T4 TBSCC patients after taking into
account the low morbidity of the procedure and the aggressiveness of the
cancer. This approach can be beneficial in a number of ways: by removing
the cervical lymph nodes, one would be able to accurately stage the neck
of and remove metastases not apparent on clinical staging, potentially
avoiding adjuvant treatment completely if histological outcomes are
favourable for this option. (24). Elective neck dissection has proved to
improve the prognosis in head and neck cancers patient(25) as only a
single modality treatment of the neck is required if pathologically N0,
avoiding adjuvant radiotherapy of the regional lymph nodes and its
related complications.(26) The low rate of occult metastases found in
our pT2 (3%) analysis and relatively small rare occurrence of T1 and T2
TBSCC would suggest that an elective neck dissection is not required
echoing the recommendations from Morris et al(17).
The role of adjuvant prophylactic radiotherapy as well as the total dose
of radiation for elective neck treatment in TBSCC patients remains
debatable. Although most clinicians would agree that radical surgery
should be followed by postoperative radiation therapy (PORT) in cases
with adverse histopathological features (eg. advanced tumours, multiple
nodal involvement, extracapsular spread, perineural invasion, positive
margins)(27, 28), the overall survival of patients with stage III-IV
disease remains low despite dual modality of treatment(29, 30).
Intensity-modulated radiotherapy (IMRT) has been shown to reduce the
severity of toxicity and significantly improve quality of life in head
and neck cancer patients (31). However, even treatment regimens
incorporating doses of IMRT with 54-63 Gy of adjuvant radiotherapy,
which is considered adequate in intermediate-risk disease management
according to NCCN guidelines (32) may be excessive in clinical N0 necks
of TBSCC patients. As there is a general consensus that single modality
of treatment should be advocated for TBSCC patients where possible, we
feel that surgical excision of the TBSCC should be accompanied by a
selective neck dissection after a multidisciplinary decision has been
made to treat the cN0 neck.