**1. Introduction**

Early stage oral cavity squamous cell carcinoma (T1N0 or T2N0) has a significant risk of between 20 and 44% [1–3] of harbouring subclinical nodal metastases. The presence of nodal metastases has been shown to be the strongest independent prognostic factor for predicting a poor outcome [4–6]. Current imaging techniques including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and ultrasound (US) cannot accurately identify micrometastases preoperatively [7, 8]. Traditionally the only way to identify this was to perform an elective neck dissection (END), however this is unnecessary in the majority (60–80%) of patients who do not harbour occult nodal metastases, and has an associated morbidity [1]. This chapter will present the histopathological factors that have been used to risk stratify patients for an END, as well as the multifaceted technique and role of sentinel lymph node biopsy (SLNB) as a staging procedure for patients with OCSCC.
