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.