Cancers of the head and neck are a diverse group of diseases arising from different subsites within the region. The incidence varies in different parts of the world, with a cumulative age-standardized incidence of 18.4 in males and 8.7 in females [1]. The majority of these cancers are tobacco-related, and the subsite affected is often determined by the patient's tobacco usage. It is primarily a locoregional disease, in which failure is more often locoregional than systemic. There is additional evidence to suggest that a higher regional burden of disease also predisposes to systemic metastases. However, certain malignancies in this area are more prone for distant dissemination – notably, the undifferentiated cancers of the nasopharynx and adenoid cystic cancers. Although advances have been made in the diagnosis and management of locoregional disease, when systemic failure does occur, there is still a paucity of effective treatment. The ability to predict those patients who will recur or have distant relapse is still not very well established.

INCIDENCE AND SITES OF METASTASIS

Nodal Metastasis in Head and Neck Cancer

The presence of a rich lymphatic network from the base of the skull to the upper mediastinum makes cancers in the head and neck region particularly prone to develop regional nodal metastasis. Nodal metastasis occurs when the lamina propria is breached by infiltrating tumor cells, which then enter the capillary lymphatics. The lymphatic channels have extensive interconnections, which often communicate with channels of the contralateral neck.