Head and neck cancers

ALSO KNOWN AS: Cancers of the mouth, sinuses, nose, salivary glands, throat, lymph nodes in neck

RELATED CONDITIONS: Squamous cell carcinoma, adenocarcinoma, oral cancer, laryngeal cancer, nasal cavity cancer, parasinus cancer, nasopharyngeal cancer, oropharyngeal cancer, hypopharyngeal cancer, salivary gland cancer

DEFINITION: Head and neck cancers refer to a wide variety of cancers occurring in the head and neck region, including cancers of the throat, mouth, voice box (larynx), salivary glands, lips, nose, and sinus cavities. Cancers of the scalp, skin, bones, muscles, brain, eye, and thyroid are not usually referred to as head and neck cancers.

Risk factors: Smoking or chewing tobacco is the greatest risk factor for head and neck cancers, linked to 85 percent of these cancers. Cigarette smokers have a markedly increased chance of developing these cancers, up to a 25 percent greater risk than nonsmokers. Smoking cigars or marijuana also increases one’s risk of getting these cancers. Alcohol use increases risk, and using alcohol and tobacco in combination increases risk even further. The use of betel (a seed chewed as a stimulant, mainly in Southeast Asia) or maté (a beverage consumed like tea, generally in South America) also increases the risk of head and neck cancer. These substances damage the squamous cells that form a lining of many structures in the head and neck. Diets rich in processed meats, red meat, and salted fish are also linked to increased risk of cancers of the head and neck.

White patches or spots in the mouth, called leukoplakia, are also a risk factor. About one-third of the time, these spots become cancerous. Some inherited conditions, like Fanconi anemia or Li-Fraumeni syndrome, also increase risk.

Other risk factors include sun exposure, radiation to the head and neck, and environmental exposure to wood dust, paint fumes, asbestos, nickel refining, textile fibers, and chemicals used by the petroleum industry. Poor oral hygiene, poor nutrition (especially low levels of vitamins A and B), a weakened immune system, gastroesophageal reflux disease (GERD), and exposure to secondhand smoke may also play a role.

Certain strains of human papillomavirus (HPV) infection, like type 16, are linked to oropharyngeal cancers of the tongue and tonsils. Epstein-Barr virus and the herpes simplex virus are also associated with a higher risk of cancer of the nose and throat.

Etiology and the disease process: Most head and neck cancers are squamous cell carcinomas that begin in the cells lining the mucosal tissues in the mouth and throat. If the cancer is limited to these cells, it is called carcinoma in situ. If it has spread into deeper tissues or other sites, it is called invasive squamous cell carcinoma.

Other head and neck cancers begin in the glands and are called adenocarcinomas. These types of cancer are much rarer than squamous cell carcinomas. Any tumors in these glands are usually benign and occur in people in their sixties and seventies. Another very rare type of head and neck cancer can begin in connective tissues.

Incidence: Head and neck cancers account for 3 to 4 percent of all types of cancer in the United States and nearly 5 percent worldwide. Experts estimate that over 70,000 people per year in the United States will develop these types of cancer, causing over 16,000 deaths.

These cancers are more common in people over fifty. They are slightly more common in men than in women and somewhat more common in Black Americans than in those of other genetic backgrounds. Men are more than twice as likely as women to die of these cancers.

Symptoms: Symptoms of these types of cancers include a sore throat, neck pain, trouble swallowing, pain when swallowing, a red or white patch in the oral cavity, bad breath, swelling of the jaw, hoarseness or a change in voice, bloody sputum, bleeding from the mouth, unexplained weight loss, fatigue, sinus congestion that does not go away, loose teeth or dentures that no longer fit properly, or a lump or sore that does not heal. Cancer of the nasal cavity or throat area may involve nosebleeds or ear pain. A less common symptom is numbness of facial muscles.

Screening and diagnosis: Many of the symptoms of head and neck cancers can be caused by other conditions, so people who use alcohol and tobacco should be screened at least yearly for head and neck cancers. Some types of tests that doctors or dentists may use to screen for these cancers are a visual inspection of the oral or nasal cavity using a small mirror and light, a physical examination for lumps, an endoscopy of the nasal or oral cavities, laboratory tests, X-rays, ultrasounds, computed tomography (CT) scans, magnetic resonance imaging (MRI), positron emission tomography (PET) scans, fine-needle aspirations, or biopsies of tissue. Surgery may be required to see if the cancer has spread to lymph nodes in the neck.

Microscopic examination of a tissue sample is required to confirm a diagnosis. After diagnosis is confirmed and the extent of the tumor or cancer has been assessed, a stage is assigned to the cancer.

The staging of head and neck cancers is rather complicated. The staging system uses the extent of the tumor’s spread as the primary basis of assigning a stage, but information on the tumor's size and whether and to what extent lymph nodes are involved is also used. A commonly used staging division is the TNM system. This system uses letters and numbers to describe the size of the tumor (T), how many lymph nodes are involved (N), and whether the cancer has spread or metastasized (M).

The tumor (T) is often assigned a number based on the primary tumor size. In some cases (for example, in a tumor in the sinus cavity), a number is assigned based on the extent to which the tumor has invaded and destroyed tissues. Designations based on the size of the tumor are as follows:

• T1: Tumor is 2 centimeters (cm) or less.
• T2: Tumor is larger than 2 cm but smaller than 4 cm.
• T3: Tumor is larger than 4 cm or multiple smaller tumors have spread to a single lymph node.
• T4: Tumors larger than 4 cm have spread to distant areas of the body.

Lymph node involvement (N) is assigned a number as follows:

• N0: No evidence of cancer exists in nearby lymph nodes.
• N1: A tumor measuring 3 cm or less is found in one lymph node on the same side as the primary tumor.
• N2: Either a tumor measuring between 3 and 6 cm is found in a lymph node on the same side as the primary tumor, tumors are in multiple lymph nodes on the same side but measure less than 6 cm, or tumors are found in lymph nodes on both sides, with the largest tumor measuring less than 6 cm.
• N3: Tumor greater than 6 cm is found in any lymph node.

The spread of the disease (M) is divided into two categories:

• M0: No disease is present elsewhere in the body.
• M1: Disease is present in a distant body area.

After determining the TNM state of the cancer, a stage is assigned.

• Stage 0: The cancer is only in the layer of cells lining the lips, mouth, or throat.
• Stage I: T1 N0 M0 tumors
• Stage II: T2 N0 M0 tumors
• Stage III: T3 N0 M0 or T1-3 N1 M0 tumors
• Stage IV: Any T4 tumor, any N2 or N3 tumor, and any M1 tumor

This staging process is complex and certainly not foolproof. For example, a small primary tumor that has spread to a lymph node on the opposite side and a large tumor that has not spread at all may be assigned the same disease stage. However, assigning a stage to the cancer can help determine treatment options.

Treatment and therapy: Treatments for head and neck cancers depend on the type of cancer, location of tumors, severity of symptoms, age and general health of the patient, stage of the cancer, and patient preference. These treatments often include surgery and may also involve radiation therapy or chemotherapy.

Some types of head and neck cancer may require surgery to remove the tumor and perhaps surrounding tissue or lymph nodes. Surgery is the type of treatment most often used for these cancers. Sometimes, the neck's nerves, muscles, glands, and veins must be removed. These removals can significantly affect a patient’s quality of life. Any surgical treatment plan should consider how surgery and removal of tissues will affect how a person breathes, eats, talks, or appears.

If the cancer has spread, radiation treatment may also be necessary following surgery. Radiation therapy can involve either a beam of radiation or the implantation of tiny radioactive “seeds” to destroy the cancerous tissues. Depending on where the cancer is located and whether it has spread, chemotherapy may also be used. Sometimes, chemotherapy is used to enhance radiation therapy.

Rehabilitation or occupational therapy can be an important part of treatment for patients who are recovering from surgery or other types of treatment for these cancers. Patients may need to relearn how to chew, swallow, or speak. Reconstructive surgery to improve the patient’s physical appearance, ability to function, or quality of life may also be part of a patient’s rehabilitation. Physical therapy may also be involved in a follow-up treatment plan, and education for patients and families, especially education about smoking cessation and any necessary diet changes, is helpful in recovery and future prevention efforts.

Prognosis, prevention, and outcomes: Even though some people with no risk factors develop head and neck cancers, most of these cancers are caused by smoking and can be prevented. When found early, these cancers are often curable. However, up to 50 percent of patients with head and neck cancers have advanced cancers by the time they are discovered. For example, more than 70 percent of throat cancers are at an advanced stage when discovered. An advanced stage of discovery reduces the chances of a cure or the ability to halt the progression of the disease.

A person who has had cancer of the head or neck is at increased risk for developing a new cancer in the head, neck, esophagus, or lungs. Usually, a recurrence or secondary cancer will happen in the first two to three years following diagnosis of the first cancer. Still, a cancer may recur up to twenty years later. These secondary tumors are a significant cause of death even after a successful course of therapy has eliminated the primary tumor. Medical professionals are currently investigating a vitamin-like substance called isotretinoin and whether it can reduce the risk of tumors recurring in the head and neck.

Stopping tobacco use is the most effective way to reduce the chance of developing head and neck cancer. Other prevention tactics include using sunscreen and eating a diet low in fat, moderate in alcohol, and high in whole grains, fruits, and vegetables.

Proper denture care can also help. Dentures that do not fit properly can trap cancer-causing substances and keep them in the mouth, increasing the chances that those substances will damage tissues.

Bibliography

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