Head and neck cancers are a heterogeneous collection of malignancies of the upper aerodigestive tract, salivary glands and thyroid. The most common type of cancer in the head and neck is squamous cell carcinoma. It mainly originates from the mucosal space, which extends from the skull base to the proximal esophagus. The head and neck region is subdivided in the oral cavity, pharynx and larynx. The pharyngeal space contains the nasopharynx, oropharynx and hypopharynx and includes the tonsils, the floor of the mouth and the soft palate. Although head and neck squamous cell carcinoma (HNSCC) is traditionally associated with smoking and alcohol drinking, a growing proportion of head and neck tumors, mainly of the oropharynx, are associated with human papilloma virus (HPV).
