Relevance of sentinel node procedures in head and neck squamous cell carcinoma.

The management of the clinically and radiologically negative neck (cN0) in patients with early oral and oropharyngeal squamous cell carcinoma (OSCC) is still a matter of debate, though most centers favor an active policy and perform END for staging of the neck and removal of occult disease. In the past decade SNB has been successfully implemented in early stage head and neck carcinomas. A large number of validation studies have shown an excellent safety profile with good sensitivity for the identification of occult neck metastases. The status of the neck is more accurately assessed by step-serial sectioning (SSS) and immunhistochemistry (IHC) of the sentinel lymph nodes (SN) compared to routine histopathologic work up of a comprehensive lymph node dissection specimen. Gain in experience as well as technical developments have lead to a wider use of SNB even in the complex lymphatic system of the Head and Neck region. First observational trials have documented its oncological accuracy and safety with success rates in controlling the neck comparable to END. The role of small tumor deposits only detectable by the extensive histopathologic work-up of the SNB-protocol is controversial. The overview comprises an introduction of the sentinel node procedure and indications in the head and neck region. The methodology as well as the histological work up and reporting of SNB is described. Finally, the clinical application, prognostic significance and future perspectives of SNB are summarized.