Head and Neck Cancer

“Head and Neck” is a broad and general term in oncology that is used to refer to the areas in this region that are most susceptible to cancer and do not include the brain, the eye, the esophagus (food pipe), thyroid glands, scalp, skin, bones, or blood; these are not classified as head and neck cancers. “Head and Neck” refers primarily to the oral cavity, salivary glands, pharynx, larynx, nasal cavity, and paranasal sinuses. Combined, these parts preform a variety of functions and make up various different systems. 

The oral cavity, also known as the mouth, includes the gums, lips, tongue, the hard palate or bone at the top of the mouth, and the bottom of the mouth below the tongue. The oral cavity is used for chewing, tasting, swallowing and manipulating air to form words.4

The salivary glands are glands found in the oral cavity (mouth) and throat. There are three types of salivary glands; the parotid gland secretes saliva near your upper teeth, the submandibular gland secretes saliva under your tongue, and the sublingual secretes saliva from the floor in your mouth. This saliva contains enzymes that chemically break down food to begin the digestion process.5

The pharynx, also known as the throat, is a hollow tube that starts behind the nose and leads to the esophagus (food pipe). It is made up of three sections, the nasopharynx (the beginning of the pharynx, behind the nose), the oropharynx (the middle part of the tube, towards the back of the mouth), and the hypopharynx (the end of the tube, near the beginning of the esophagus). The pharynx serves digestive and respiratory functions as a passageway for food and air. 

The larynx, also known as the voicebox, is another short tube found in the neck. It starts at the bottom of the pharynx, although it is separate from the esophagus (food pipe), and continues down to the trachea (wind pipe). The vocal cords and a flap of tissue that contracts during swallowing called the epiglottis are found in the larynx and help it perform its primary functions. The larynx serves to prevent food from entering the trachea (wind pipe), keep the airway open, and help with vocalization.6

The nasal cavity is the hollow space inside the nose. It helps filter and provide passage of air into lungs, as well as providing your sense of smell. Similarly, paranasal sinuses are small hollow spaces in the head surrounding the bone. These sinuses serve various functions, including humidifying and warming up inhaled air and serving as a protective barrier in facial trauma.7

Head and neck cancer may be located in any of the following:

• oral cavity
• salivary glands
• pharynx
• larynx
• nasal cavity and paranasal sinuses

Cancer in the eye, brain, scalp, skin, muscles, as well as bone and blood in this area are not considered head and neck cancers.

Most head and neck cancer is found in the squamous epithelialA type of tissue (epithelium) that covers our exposed surfaces, such as skin. Also lines our hollow or tube-like organs/tissues such as the digestive tract. Since these tissues are often exposed to environmental insults such as chemicals and solar radiation and are often divide rapidly to replace lost cells, many cancers arise in epithelial tissues. cells (flat cells that line moist, mucus membranes) of these structures, and these cancerous cells are called carcinomas. Cancer that is limited to this outer, lining layer of cells is called carcinomaCancer of epithelial cells, the cells that cover the outside and inside of body surfaces. This is the most common form of cancer. in situFrom the Latin, . Cancer that grows beyond this layer into the deeper tissue is called invasive squamous cell carcinoma.

However, because there are many different tissues that make up the head and neck, especially with regards to the salivary gland and nasal cavity, there are many other types of cancerous cells that be considered head and neck cancer.

The following are risk factors for the different types of head and neck cancer:8, 9, 10, 11, 12

• Alcohol Consumption and Tobacco Use
• Pre-existing Conditions and Infection
• Family History
• Age
• Gender
• Nutrition
• Workplace Exposure
• Oral Hygiene
• RadiationIn cancer biology: A cancer treatment in which high energy beams are used to kill cancer cells. Radiation can also cause genetic damage that can lead to cancer. As an example, skin cancer is believed to be greatly increased by exposure to ultraviolet (UV) radiation from the sun.

Alcohol Consumption and Tobacco Use

These are the two most common risk factors for head and neck cancer, especially cancers of the oral cavity, oropharynx, hypopharynx and larynx. Tobacco alone accounts for more than 75% of all cases of head and neck cancer. For more information on the risks tobacco pose, visit CancerQuest’s page on tobacco. Heavy drinkers are also more likely to develop head and neck cancer. Combined, these two factors create the greatest risk of all and people who both smoke and drink are many times more likely to develop head and neck cancer than people who only do one or neither.  

Pre-existing Conditions or Infections

Certain pre-existing conditions or infections can be risk factors for specific types of head and neck cancer. 

The infection most highly linked with the most types of head and neck cancer is the human papillomavirus (HPV). HPV is explained thoroughly on the Cervical Cancer: Risk Factors page. HPV causes wart growths called papillomas aroun the affected area. Different types of HPV are found in different areas of the body; the type that causes head and neck cancers is HPV 16. While it is rare for people to develop oropharyngeal cancer from an HPV infection, the number of cases linked to HPV has increased dramatically and 2 out of 3 cases are found to contain HPV DNAAbbreviation for deoxyribonucleic acid. Composed of very long strings of nucleotides, which are abbreviated as A, C, G and T. DNA is the storage form of our genetic material. All of the instructions for the production of proteins are encoded in our DNA. .  

The Epstein-Barr virusThe smallest type of organism known. A single virus particle (called a virion) is much smaller than a cell. Viruses reproduce by invading cells and forcing the cells to make progeny virions. Viruses generally have specific host cells which they infect. Some virus types are associated with specific cancers and can convert normal cells into cancer cells. Examples of viruses associated with cancer are: papillomavirus-cervical cancer, hepatitis virus-liver cancer, Epstein-Barr virus-Burkitt's lymphoma. Virus-induced transformation of cells was one of the very first model systems for the study of cancer. Viruses have also been a key tool in the identification of many oncogenes. Because of their great ability to enter target cells viruses such as adenoviruses are being examined for their ability to deliver genes to cancer cells. (the virus most commonly know to cause mononucleosis or “mono") has also been linked to many cases of head and neck cancer. It can cause salivary gland cancer and nasopharyngeal cancer. 

There are many less associated conditions and diseases that can also cause certain types of head and neck cancer. Fanconi anemia and Dyakeratosis congenital are both conditions caused by inherited defects in certain genes and people with these genetic disorders have a very high risk of oral, oropharyngeal, laryngeal and hypopharyngeal cancer. Graft-versus-host disease (GVHD), which sometimes occurs after a stem cellCells capable of developing into more than one cell type. All of the cells in a human body come from the division and subsequent differentiation of a single cell, formed from the fusion of an egg and sperm. This original cell has the capability to form any cell type and is called totipotent. As tissues develop the cells lose the ability to form all other tissues, and become 'committed' to forming only one or a few cell types. These stem cells are called pluripotent. An example are bone marrow cells that form many different kinds of blood cells. Stem cell replacement allows for the pluripotent stem cells in bone marrow to be replaced after high doses of chemotherapy. Many fully differentiated cells are not capable of cell division and are replaced when they die by the division of stem cells in that tissue. Many forms of cancer are thought to be the result of abnormal division of stem cells. transplant has been linked to oral cancer. Lastly, in a few, rare cases, Lichen planus, a disease that affects the skin in middle-aged people, has been shown to slightly increase the risk of oral cancer. 

Family History

 People with a family history of nasopharyngeal and salivary gland cancer may be more likely to contract those two types of head and neck cancer. However, most cases of salivary gland cancer do not have any family history. 

Age

 For all types of head and neck cancer, like most other cancers, risk increases with age. Most cases of head and neck cancer are found in people 50 years or older. However, because of the prevalence of the HPV virus among teens, the average patient with head and neck cancer is getting younger.

Gender

It has been found that men are more likely to contract head and neck cancer than women. 

Nutrition

 Vitamin deficiencies, as a result of excessive alcohol consumption or a diet high in fat and low in vegetables, can increase risk of getting head and neck cancer. Furthermore, certain practices of preserving food in salt, which is common in eastern Asia,  or consumption of mate, a tea like beverage in South America, can increase this risk of getting head and neck cancer.  

Workplace Exposure

 Exposure to and breathing in dusts from certain substances, including wood, textiles, leather, nickel and chromium, can increase risk. Flour, formaldehyde, mustard gas, radium, glue and asbestos can also contribute to higher risk. 

Oral Hygiene

 Practicing poor oral hygiene or using mouthwash containing too much alcohol has been debatably linked to a higher risk of oral cancer. 

Radiation

Prolonged exposure to sunlight or x-rays can increase risk of cancer.

Early stages of head and neck cancers present very few noticeable symptoms so dentists, physicians and oral surgeons have to be on the look out for anything suspicious. If a patient shows symptoms or is suspected to have head and neck cancer, a physical examination is preformed to find any abnormalities such as white mucusy or red patches. If these are found then there is an array of different techniques to help stage or further classify the type of cancer.

An endoscopy, a procedure to look at the digestive tract, is the most accurate way to classify and diagnose head and neck cancers. It is recommended for patients diagnosed with any type of head and neck cancer to get an endoscopy. Biopsies are then performed on any abnormalities found during the physical exam or endoscopy. Radiological evaluations are used to determine staging. While in the past this was traditionally done with MRIAlso: nuclear magnetic resonance imaging (NMR). Magnetic Resonance Imaging is a non-invasive imaging procedure that utilizes strong magnets and radio waves to visualize tissues. Subtle differences in the ways that the tissues and organs absorb and reflect the waves enable the detection of many different disorders. or CT scans, new studies are showing that PET scans may provide a more accurate evaluation. These evaluations are done at the primary site of cancer and the neck. However, new findings have shown new non-invasive methods that could possibly be used to diagnose head and neck cancers. DNA analysis from blood or other bodily fluids could show mutations linked to cancer or the presence of EPV or HPV DNA, which have also been linked to head and neck cancer. Furthermore, molecular studies of areas directly surrounding a tumor could help determine staging and treatment options.

13, 14, 15, 16, 17

All Head and Neck cancers can be staged using the T/N/M system, which assigns a degree of severity based on size, location and spread of the cancer in the body. This degree is assigned a number I-IV and that is the stage of the cancer. Each type of Head and Neck cancer has different staging criteria which you can learn more about from the American Cancer Society using these links: 

• Nasopharyngeal cancer
• Laryngeal/Hypopharyngeal cancer
• Oral Cavity/Oropharyngeal cancer
• Salivary Gland cancer
• Nasal/Paranasal cancer

The treatment of head and neck cancers varies by primary site and stage. As our focus is on the biology of the cancers and not their treatments, we do not give detailed treatment guidelines. Instead, we link to organizations in the U.S. that generate the treatment guidelines. 

 Consult with your doctor to determine specific treatments for your type of cancer because different primary sites respond better to different treatment options. However, the National Comprehensive Cancer Network (NCCN) lists the following treatments for most types of Head and Neck cancer:

 -Surgery 

-Radiation Therapy 

-ChemotherapyTreatment of cancer patients with anticancer drugs. Commonly called 'chemo'. These drugs work by attacking cell growth or division. Often these agents are used in combination to take advantage of their different modes of attack on cell division.