Long-Term Experience in Sentinel Node Biopsy for Early Oral and Oropharyngeal Squamous Cell Carcinoma

The presence of nodal disease is a key prognostic indicator in oral cavity and oropharyngeal carcinoma. Detection and management strategies for occult nodal metastasis in oral cavity and oropharyngeal squamous cell carcinoma (OSCC) continue to pose considerable controversy. Clinically negative (cN0) necks in early-stage OSCC tend to harbor occult disease within the cervical lymph nodes in 20–30% of cases. This high rate of occult nodal metastasis generates substantial clinical interest in optimizing accurate histopathological staging of the neck. The effectiveness of sentinel node biopsy (SNB) has been studied as a potential minimally invasive technique for accurately predicting pathological nodal status. In this study, Broglie et al. prospectively assess the longterm experience and survival data utilizing SNB as a staging tool. Their cohort consisted of 58 patients of whom 29 had a (-) SNB and 29 had a (?) SNB and who were followed by neck dissection. The addition of postoperative radiation was restricted to those patients with pN2b/c disease and (?) ECS only. Similar to other solid tumor models, including breast, there are efficiencies that are intuitively attractive in performing SNB versus staging neck dissections for OSCC. However, several quandaries still exist in implementing SNB as standard of care for staging patients with OSCC for END. The false-negative rate was reported in this study as 10% (3/29) in those patients with negative SNB. Presumably these patients would have been appropriately staged and/or treated with selective neck dissection. The authors also indicated that 1/29 patients with SNB (?) had contralateral recurrence, which could indicate a potentially missed sentinel node resulting in persistent disease. Previous studies have reported contralateral sentinel lymph nodes occurring in up to 20% of cases. Conversely, in the survival analysis performed by Broglie et al., patients exhibited 5 year OS, DFS, and DSS of 88, 96, and 96% versus 74, 73, and 77% in (-) SNB compared with (?) SNB, respectively. The DSS in the latter group was statistically significant and demonstrated a persistently poor survival rate in those patients with early stage OSCC and cN0, regardless of having undergone SNB and subsequent END for pathologically node-positive disease. So, although delayed nodal metastases during a waitand-scan policy portend poor overall prognosis, it is unclear if sentinel node biopsy results in any comparable improvement in survival. In view of rising healthcare costs, it is essential to study the survival impact and the cost-effectiveness of performing SNB. Thus, although this study is limited by its cohort size, it would be necessary to demonstrate a survival advantage prior to subjecting patients with a cN0 neck to SNB instead of a wait-and-scan policy. This is especially true if approximately three-quarters of patients (SNB negative) will undergo the procedure with no survival benefit. Moreover, those patients who were identified as the ‘‘high-risk’’ group and selected for END through a (?) SNB still had a lower survival rate yet incurred an additional procedure prior to definitive neck dissection. It is also difficult to define data regarding the surgical complication and morbidities of staging neck dissection compared with sentinel node biopsy. Although the authors’ results are encouraging in demonstrating the feasibility and reliability of SNB, continued Society of Surgical Oncology 2011