What is Head and Neck Cancer?

This is the first article in the Understanding Head and Neck Cancer Guide. This guide was developed by the HealthTree Education Team and was last updated and reviewed on May 22, 2026

Cancer begins when cells in the body start to grow out of control. Head and neck cancer starts in the cells that line the moist surfaces inside the mouth, throat, voice box, sinuses, and nasal cavity, or in the cells of the salivary glands. Most head and neck cancers begin in the thin, flat cells called squamous cells.

When you have head and neck cancer, cells in these tissues do not follow the normal cell cycle. Healthy cells grow, copy themselves, and then die. Cancer cells change, grow faster than normal, and do not die the way they should.

What are the head and neck?

The head and neck region includes many structures involved in breathing, eating, speaking, and the senses of smell, taste, and hearing. Head and neck cancers are usually grouped by the area where they begin:

• Oral cavity (mouth). Includes the lips, the front two-thirds of the tongue, the gums, the inside lining of the cheeks and lips, the floor of the mouth under the tongue, the hard palate (roof of the mouth), and the small area behind the wisdom teeth.
• Pharynx (throat). A hollow tube about 5 inches long that starts behind the nose and leads to the esophagus. It has three parts:
  • The nasopharynx. The upper part behind the nose.
  • The oropharynx. The middle part which includes the base of the tongue, tonsils, soft palate, and back walls of the throat.
  • The hypopharynx. The lower part.
• Larynx (voice box). A short passageway just below the pharynx in the neck that contains the vocal cords. The epiglottis, a small flap of tissue, covers the larynx to keep food out of the airway during swallowing.
  Paranasal sinuses and nasal cavity. The small hollow spaces in the bones of the head surrounding the nose, and the hollow space inside the nose.
• Salivary glands. Glands that produce saliva. The major salivary glands are the parotid glands (in front of the ears), the submandibular glands (under the jaw), and the sublingual glands (under the tongue). Hundreds of minor salivary glands are scattered throughout the lining of the mouth and throat.

Cancers of the brain, eye, esophagus, thyroid gland, and skin of the head and neck are generally not classified as head and neck cancers, even though they occur in the same region. They are treated as separate diseases.

How head and neck cancer starts

Most head and neck cancers develop when changes build up in the DNA of cells lining the mouth, throat, or voice box. These changes can be caused by tobacco use, alcohol, or infection with high-risk types of human papillomavirus (HPV), particularly HPV-16. Over time, these damaged cells can grow out of control. HPV-positive and HPV-negative head and neck cancers behave differently and are increasingly treated as distinct diseases.

How does head and neck cancer affect the body?

As head and neck cancer grows, it can affect many parts of the body:

How head and neck cancer affects the head and neck:

Head and neck cancer often causes symptoms in the area where it begins. Tumors can interfere with chewing, swallowing, speaking, breathing, and the senses of taste and smell. They can also cause visible lumps in the neck, sores in the mouth that do not heal, or changes in the voice.

How head and neck cancer affects the lymph nodes:

Head and neck cancer often spreads first to lymph nodes in the neck. A painless lump in the neck is one of the most common early signs. The pattern of lymph node involvement helps guide both staging and treatment.

How head and neck cancer affects other organs:

When cancer spreads to other parts of the body, it has metastasized. Head and neck cancer most commonly spreads to lymph nodes in the neck. When it spreads beyond the neck, it most often travels through the bloodstream to the lungs, and less commonly to the liver or bones. This can affect how these organs function and may cause additional symptoms.

Learn more about the signs and symptoms of head and neck cancer.

Types of head and neck cancer

Head and neck cancers are usually classified by the area where they begin and by the type of cell involved. The vast majority are squamous cell carcinomas:

• Oral cavity cancer. Cancers of the lip, tongue, gums, cheek lining, floor of the mouth, and hard palate. Strongly linked to tobacco and alcohol use.
• Oropharyngeal cancer. Cancers of the tonsils, base of the tongue, soft palate, and back of the throat. The majority of new cases in the United States are now caused by HPV infection and tend to occur in younger, non-smoking patients. HPV-positive oropharyngeal cancers respond better to treatment than HPV-negative cancers.
• Laryngeal cancer. Cancer of the voice box. Most often presents with persistent hoarseness. Strongly linked to tobacco and alcohol use.
• Hypopharyngeal cancer. Cancer of the lower part of the throat. Often diagnosed at a later stage because early symptoms are subtle.
• Nasopharyngeal cancer. Cancer of the upper part of the throat behind the nose. Strongly linked to Epstein-Barr virus (EBV) infection and more common in parts of Asia, North Africa, and the Middle East.
  Nasal cavity and paranasal sinus cancer. A rare group of cancers. Risk factors include occupational exposures to wood dust, nickel, and certain chemicals.

Salivary gland tumors

Salivary gland cancers are uncommon and include a wide range of subtypes that behave very differently. The most common types include mucoepidermoid carcinoma, adenoid cystic carcinoma, acinic cell carcinoma, and salivary duct carcinoma. Many salivary gland tumors are not cancerous, particularly those in the parotid gland.

Other less common head and neck cancers

Less common cancers in the head and neck region include lymphomas of the tonsils or other lymphoid tissue, sarcomas, mucosal melanomas, and rare cancers such as olfactory neuroblastoma. These are treated differently than squamous cell carcinomas.

Related conditions

Certain conditions can be associated with a higher risk of developing head and neck cancer:

• Leukoplakia and erythroplakia. White (leukoplakia) or red (erythroplakia) patches in the mouth or throat that do not rub off. Some of these patches can progress to cancer over time and should be evaluated by a doctor or dentist.
• HPV infection. Infection with high-risk types of human papillomavirus, particularly HPV-16, is a major cause of oropharyngeal cancer. Most people exposed to HPV clear the infection without developing cancer.
• Hereditary cancer syndromes. Rare inherited conditions such as Fanconi anemia, dyskeratosis congenita, and Li-Fraumeni syndrome significantly increase the lifetime risk of head and neck cancer.