Head and neck cancer are cancers that usually begin in the squamous cells that line the moist, mucosal surfaces inside the head and neck – for example, inside the mouth, the nose, and the throat.

Often referred to as the squamous cell carcinomas of the head and neck, head and neck cancers can also begin in the salivary gland, but it is uncommon.

Head and neck cancers are categorised according to the region they begin, such as:

• Oral Cavity – Includes the lips, the front two-thirds of the tongue, the gums, the lining inside the cheeks and lips, the floor of the mouth under the tongue, the hard palate, and the small area of the gum behind the wisdom teeth.
• Pharynx: The pharynx (throat) is a hollow tube about 5 inches long that starts behind the nose and leads to the oesophagus. It has three parts: the nasopharynx(the upper part of the pharynx, behind the nose); the oropharynx (the middle part of the pharynx, including the soft palate [the back of the mouth], the base of the tongue, and the tonsils); the hypopharynx (the lower part of the pharynx).
• Larynx: The larynx, also called the voicebox, is a short passageway formed by cartilage just below the pharynx in the neck. The larynx contains the vocal cords. It also has a small piece of tissue called the epiglottis, which moves to cover the larynx to prevent food from entering the air passages.
• Paranasal sinuses and nasal cavity: The paranasal sinuses are small hollow spaces in the bones of the head surrounding the nose. The nasal cavity is the open space inside the nose.
• Salivary glands: The major salivary glands are on the floor of the mouth and near the jawbone. The salivary glands produce saliva.