Overview

Cancers of the oral cavity are the most common type of head and neck cancer and the sixth most common cancer worldwide. Nearly 30,000 new cases of oral cancer are diagnosed in the US each year. Oral cancer begins in the mouth, or oral cavity, which includes the lips, the gums, the area behind the molars or wisdom teeth, the inside of the lips and cheeks, the floor and roof (known as the hard palate) of the mouth, and the front two-thirds of the tongue.

The main risk factors for oral cancer are chewing or smoking tobacco, drinking alcohol excessively, and chewing betel (or areca) nuts. Sun exposure and human papilloma virus (HPV), a diverse group of viruses that infect the skin and mucous membranes, are risk factors less frequently linked to oral cancer. Most oral cancers arise in the tongue (28 percent), the lip (23 percent), the floor of the mouth (16 percent), and the minor salivary glands (11 percent). The rest are found in the gums and other sites. The most common symptoms include a sore or persistent lump on the lip or in the mouth that does not heal; a white and/or red patch on the gums, tongue, or cheeks (these white or red areas may also be a precancerous condition called dysplasia); unusual or persistent bleeding, pain, or numbness in the mouth; and swelling that causes dentures to fit poorly or become uncomfortable. Dentists or dental hygienists are often the first to spot these problems. If discovered early, most oral cancers can be cured.

Sun exposure is also a risk factor for skin cancer. To find more information about skin cancer, visit that section of our Web site.

Laryngeal cancer begins in the larynx, the organ also known as the voice box. The larynx sits at the top of the trachea -- the tract that leads to the lungs -- and is surrounded by a swallowing tube (the hypopharynx). The larynx is visible on most men's throats as the Adam's apple. Air passes through the larynx on the way to the lungs. The vocal cords, two bands of muscle, are found within the larynx and are used to make speech. The larynx also prevents food from entering the lungs. Each year about 11,300 new cases of laryngeal cancer are diagnosed in the US, the vast majority of them among men.

Tobacco and alcohol use are the major risk factors for laryngeal cancer. Other risk factors include: occupational exposure to wood and metal dusts, asbestos, paint fumes, and other chemical inhalants; a diet low in vitamins A and E; gastroesophageal reflux disease, in which the throat is chronically exposed to stomach acid; and exposure to human papilloma virus. The most common symptoms include hoarseness, ear pain, and difficulty swallowing.

Pharyngeal cancer arises in the pharynx, the hollow tube inside the neck that starts behind the nose and ends at the top of the windpipe and esophagus. Tumors in this region include cancer of the nasopharynx (the upper part of the throat behind the nose), the oropharynx (the middle part of the pharynx), and the hypopharynx (the bottom part of the pharynx). This year 11,800 people in the US will develop pharyngeal cancers.

• Nasopharyngeal Cancer

  The nasopharynx is the uppermost portion of the throat (pharynx); it begins just behind the nose and extends to the portion of the throat found just behind the mouth (oropharynx), and includes two openings that lead to the ears. Nasopharyngeal cancer is less often related to tobacco than other head and neck cancers. Risk factors include exposure to Epstein-Barr virus, a member of the herpes virus family and one of the most common human viruses. This type of cancer is much more common in Asia, especially southeast China, and Africa than in the US, and may be linked to eating salt-cured fish.

• Oropharyngeal Cancer

  Oropharyngeal cancer develops in the section of the throat (oropharynx) located just beyond the mouth, which includes the base of the tongue, the soft palate (the soft area just beyond the roof of the mouth), and the area around the tonsils. Smoking and chewing tobacco and heavy alcohol use are the risk factors most commonly linked to this type of cancer, but there is also evidence that a diet low in fruits and vegetables, drinking maté (a stimulant drink common in South America), chewing betel nuts, and infection with human papillomavirus (HPV) may also play a role in the disease. HPV infection is most clearly linked to this form of head and neck cancer.¹

• Hypopharyngeal Cancer

  Hypopharyngeal cancer develops in the hypopharynx, which is the uppermost portion of the esophagus (the tube through which food travels to the stomach). The hypopharynx surrounds the larynx. About 2,500 new cases of this form of cancer are diagnosed each year. As with most other head and neck cancers, smoking and chewing tobacco and heavy alcohol use are the most common risk factors linked to this type of cancer, but there is also evidence that a diet low in fruits and vegetables and Plummer-Vinson syndrome (a rare condition that causes difficulty swallowing) may be risk factors as well.

Cancers that arise in the mucus-producing tissues that line the paranasal sinuses (hollow areas in the bones of the face near the nose) and the nasal cavity (the space just behind the nose through which air passes to the throat) are called nasal cavity and paranasal sinus cancers. Cancer in the skull base region of the head is rare: about 2,000 people in the United States develop this form of cancer each year. Most cancers of the nasal cavity and paranasal sinuses (60 to 70 percent) occur in the maxillary sinuses, the hollow spaces on either side of the nose just below the eyes; fewer develop in the nasal cavity (20 to 30 percent) and in the ethmoid sinuses, the hollow spaces behind the bridge of the nose (10 to 15 percent). People who smoke and those who are exposed in the workplace to metal and wood dust and toxic fumes appear to have a heightened risk of developing cancer in the paranasal sinuses and nasal cavity.

The salivary glands are structures that produce saliva, which keeps the mouth from drying out and contains enzymes that begin the breakdown of food. There are two categories of these glands -- major salivary glands and minor salivary glands. Major salivary glands are located under the jaw, in front of the ears, underneath the tongue, and in the nose, sinuses, mouth, and throat. There are also several hundred minor salivary glands located throughout the mouth and throat.

Many types of benign and malignant tumors can develop in these glands, depending on the type of cells from which they arise; these tumors are rare. Most salivary gland tumors begin in one of the largest of the salivary glands -- the two parotid glands, located in front of the ears on each side of the face. Tumors can also arise in the submandibular glands, which are tiny glands found on either side of the neck, under the chin and tongue area, and in the hundreds of microscopic minor salivary glands located beneath the lining of the lips, tongue, hard and soft palate, and the inside of the cheeks, nose, sinuses, and voice box (larynx). The causes of most salivary gland tumors are unknown, but risk factors may include radiation treatments to the head, occupational exposure to radiation, and exposure to certain metals and minerals. Tobacco use may be linked to cancer that develops in the squamous cells of the salivary gland, but most of these cancers arise in another glandular type of cell.

Thyroid cancer develops in the thyroid gland, a small butterfly-shaped structure that wraps around the front of windpipe in the lower part of the neck. The thyroid gland is the source of important hormones that help regulate metabolism, blood pressure, heart rate, temperature, and other functions. About 33,550 people are diagnosed with thyroid cancer each year. Thyroid cancer usually appears first as a small lump or swelling, called a nodule, which can be felt on the front of the neck. Thyroid nodules are common, and in more than 90 percent of cases, they are benign. The only documented risk factor of thyroid cancer is exposure to high levels of external radiation at a young age. These higher than normal levels of radiation may come from the environment or be a result of prior radiation treatment to the head and neck area.

For more information about thyroid cancer, visit that section of our Web site.

Parathyroid tumors are very rare (about 100 cases are diagnosed in the US annually) and develop in the gland located at the base of the front of the neck, near the thyroid gland. Normally, the parathyroid gland produces parathyroid hormone (PTH), which helps the body store and use calcium. Problems with the parathyroid gland are common and are not usually cancer related. When parathyroid cancer does develop, it causes the parathyroid to make too much PTH. The extra PTH takes calcium from the bones, causing pain, kidney problems, and other disorders that result when too much calcium is in the blood.

For more information about parathyroid tumors, click here to visit the Rare Solid Tumor section of our Web site.

¹D. I. Kutler, V. B. Wreesman, A. Goberdhan, et al., Human papillomavirus DNA and p53 polymorphisms in squamous cell carcinomas from Fanconi anemia patients, Journal of the National Cancer Institute 95(22), 2003: 1718-21.