Cancer of the Mouth and Throat

Cancer of the Mouth and Throat Overview

The oral cavity (mouth) and the upper part of the throat (pharynx) have roles in many important functions, including breathing, talking, chewing, and swallowing. The mouth and upper throat are sometimes referred to as the oropharynx or oral cavity. The important structures of the mouth and upper throat include the following:

• Lips
• Inside lining of the cheeks (buccal mucosa)
• Teeth
• Gums
• Tongue
• Floor of the mouth
• Back of the throat, including the tonsils (oropharynx)
• Roof of the mouth (the bony front part [hard palate] and the softer rear part [soft palate])
• Area behind the wisdom teeth
• Salivary glands

Picture of oral cancer (cancer of the mouth)

Many different cell types make up these different structures. Cancer occurs when normal cells undergo a transformation whereby they grow and multiply without normal controls. Malignant tumors of the oral cavity can encroach on and invade neighboring tissues. They can also spread to remote sites in the body through the bloodstream or to lymph nodes via the lymph vessels. The process of invading and spreading to other organs is called metastasis.
Tumors in the mouth and throat include both benign and malignant types.

• Benign tumors, although they may grow and penetrate below the surface layer of tissue, do not spread by metastasis to other parts of the body. Benign tumors of the oropharynx are not discussed in this article.

Premalignant conditions are cell changes that are not cancer but which may become cancer if not treated.

• Dysplasia is another name for these precancerous cell changes.
• Dysplasia can be detected only by taking a biopsy of the lesion.
• Examining the dysplastic cells under a microscope indicates how severe the changes are and how likely the lesion is to become cancerous.
• The dysplastic changes are usually described as mild, moderately severe, or severe.

The two most common kinds of premalignant lesions in the oropharynx are leukoplakia and erythroplakia.

• Leukoplakia is a white or whitish area on the tongue or inside of the mouth. It can often be easily scraped off without bleeding and develops in response to chronic (long-term) irritation. Only about 5% of leukoplakias are cancerous at diagnosis or will become cancerous within 10 years if not treated.
• Erythroplakia is a raised, red area. If scraped, it may bleed. Erythroplakia is generally more severe than leukoplakia and has a higher chance of becoming cancerous over time.
• Mixed white and red areas can also occur and represent premalignant lesions of the oral cavity.
• These are often detected by a dentist at a routine dental examination.

Several types of malignant cancers occur in the mouth and throat.

• Squamous cell carcinoma is by far the most common type, accounting for more than 90% of all cancers. These cancers start in the squamous cells, which form the surface of much of the lining of the mouth and pharynx. They can invade deeper layers below the squamous layer.
• Other less common cancers of the mouth and throat include tumors of the minor salivary glands and lymphoma.
• Cancers of the mouth and throat do not always metastasize, but those that do usually spread first to the lymph nodes of the neck. From there, they may spread to more distant parts of the body.

Statistics about oral cancer reveal that over 39,000 new cases of oral cancer are diagnosed in the U.S. yearly, with about 7,900 people dying of these cancers each year. Approximately 1 out of 95 people will develop an oral cancer at some time in their lives.

• Cancers of the mouth and throat occur in twice as many men as women.
• These cancers can develop at any age but occur most frequently in people aged 45 years and older.
• Incidence rates of mouth and throat cancers vary widely from country to country. These variations are due to differences in risk factor exposures.

Mouth and Throat Cancer Causes

Tobacco use is by far the most common risk factor for cancers of the mouth and throat. Both smoking and "smokeless" tobacco (snuff and chewing tobacco) increase the risk of developing cancer in the mouth or throat.

• All forms of smoking are linked to these cancers, including cigarettes, cigars, and pipes. Tobacco smoke can cause cancer anywhere in the mouth and throat as well as in the lungs, the bladder, and many other organs in the body. Pipe smoking is particularly linked with lesions of the lips, where the pipe comes in direct contact with the tissue.
• Smokeless or chewing tobacco is linked with cancers of the cheeks, gums, and inner surface of the lips. Cancers caused by smokeless tobacco use often begin as leukoplakia or erythroplakia.

Other risk factors for mouth and throat cancer include the following:

• Alcohol use: At least three quarters of people who have a mouth and throat cancer consume alcohol frequently. People who drink alcohol frequently are six times more likely to develop one of these cancers. People who both drink alcohol and smoke often have a much higher risk than people who use only tobacco alone.
• Sun exposure: Just as it increases the risk of skin cancers, ultraviolet radiation from the sun can increase the risk of developing cancer of the lip. People who spend a lot of time in sunlight, such as those who work outdoors, are more likely to have cancer of the lip.
• Chewing betel nut: This prevalent practice in India and other parts of South Asia has been found to result in mucosa carcinoma of the cheeks. Mucosa carcinoma accounts for less than 10% of oral cavity cancers in the United States but is the most common oral cavity cancer in India.
• Human papillomavirus (HPV) infection: Several strains of HPV are associated with cancers of the cervix, vagina, vulva, and penis. Some types of HPVs are able to infect the tissues of the mouth and throat. Cancer at the base of the tongue, at the back of the throat, in the tonsils, or in the soft palate is associated with HPV infection.

These are risk factors that can be avoided in some cases. For example, one can choose to not smoke, thus lowering the risk of mouth and throat cancer. The following risk factors are outside of a person's control:

• Age: The incidence of mouth and throat cancers increases with advancing age.
• Sex: Mouth and throat cancer is twice as common in men as in women. This may be related to the fact that more men than women use tobacco and alcohol.

The relationship between these risk factors and an individual's risk is not well understood. Many people who have no risk factors develop mouth and throat cancer. Conversely, many people with several risk factors do not. In large groups of people, these factors are linked with higher incidence of oropharyngeal cancers.

Mouth and Throat Cancer Symptoms

People may not notice the very early symptoms or signs of oral cancer. People with an oropharyngeal cancer may notice any of the following signs and symptoms:

• A painless lump on the lip, in the mouth, or in the throat
• A sore on the lip or inside the mouth that does not heal
• A painless white or red patch on the gums, tongue, or lining of the mouth
• Unexplained pain, bleeding, or numbness inside the mouth
• A sore throat that does not go away
• Pain or difficulty with chewing or swallowing
• Swelling of the jaw
• Hoarseness or other change in the voice
• Pain in the ear

Oral squamous cell cancer appearing as a tongue ulcer. SOURCE: Image reprinted with permission from Medscape.com, 2012.

These symptoms are not necessarily signs of cancer. Mouth sores and other symptoms may be caused by many other less serious conditions.

When to Seek Medical Care

If a person has any of the symptoms of head and neck cancer, he or she should make an appointment to see a primary care professional or dentist right away.

Mouth and Throat Cancer Diagnosis

Cancers of the mouth and throat are often found on routine dental examination. If a dentist should find an abnormality, he or she will probably refer the person to a specialist in ear, nose, and throat medicine (an otolaryngologist) or recommend that they see a primary health care professional right away.
If symptoms are found that suggest a possible cancer, or if an abnormality is found in the oral cavity or pharynx, the health care professional will immediately begin the process of identifying the type of abnormality.

• The goal will be to rule out or confirm the diagnosis of cancer.
• He or she will interview the patient extensively, asking questions about medical and surgical history, medications, family and work history, and habits and lifestyle, focusing on the risk factors for oropharyngeal cancers.

At some point during this process, the person will probably be referred to a physician who specializes in treating cancers of the mouth and throat.

• Many cancer specialists (oncologists) specialize in treating cancers of the head and neck, which includes cancers of the oropharynx.
• Every person has the right to seek treatment where he or she wishes.
• The patient may want to consult with two or more specialists to find one who makes him or her feel most comfortable.

The patient will undergo a thorough examination of the head and neck to look for lesions and abnormalities. A mirror exam and/or an indirect laryngoscopy (see below for explanation) will most likely be done to view areas that are not directly visible on examination, such as the back of the nose (nasopharyngoscopy), the throat (pharyngoscopy), and the voice box (laryngoscopy).

• The indirect laryngoscopy is performed with the use of a thin, flexible tube containing fiberoptics connected to a camera. The tube is moved through the nose and throat and the camera sends images to a video screen. This allows the physician to see any hidden lesions.
• In some cases, a panendoscopy may be necessary. This includes endoscopic examination of the nose, throat, and voice box as well as the esophagus and airways of the lungs (bronchi). This is done in an operating room while the patient is under general anesthesia. This gives the most exhaustive possible examination and can permit biopsies of areas suspicious for malignancy.
• The complete physical examination will look for signs of metastatic cancer or other medical conditions that could affect the diagnosis or treatment plan.

No blood tests can identify or even suggest the presence of a cancer of the mouth or throat. The appropriate next step is biopsy of the lesion. This means to remove a sample of cells or tissue (or the entire visible lesion if small) for examination.

• There are several techniques for taking a biopsy in the mouth or throat. The sample can be simply scraped from the lesion, removed with a scalpel, or withdrawn with a needle.
• This can sometimes be done in the medical office; other times, it needs to be done in a hospital.
• The technique is dictated by the size and location of the lesion and by the experience of the person collecting the biopsy.
• If there is a mass in the neck, that may be sampled as well, usually by fine-needle aspiration biopsy.

After the sample(s) is removed, it will be examined by a doctor who specializes in diagnosing diseases by examining cells and tissues (pathologist).

• The pathologist looks at the tissue under a microscope after treating it with special stains to highlight certain abnormalities.
• If the pathologist finds cancer, he or she will identify the type of cancer and report back to the health care professional.

If your lesion is cancer, the next step is to stage the cancer. This means to determine the size of the tumor and its extent, that is, how far it has spread from where it started. Staging is important because it not only dictates the best treatment but also the prognosis for survival after treatment.

• In oropharyngeal cancers, the stage is based on the size of the tumor, involvement of the lymph nodes in the head and neck, and evidence of spread to distant parts of the body.
• Like many cancers, cancers of the oral cavity and pharynx are staged as 0, I, II, III, and IV, with 0 being the least severe (cancer has not yet invaded the deeper layers of tissue under the lesion) and IV being the most severe (cancer has spread to an adjacent tissue, such as the bones or skin of the neck, to many lymph nodes on the same side of the body as the cancer, to a lymph node on the opposite side of the body, to involve critical structures such as major blood vessels or nerves, or to a distant part of the body).

Stage is determined from the following information:

• Physical examination findings
• Endoscopic findings
• Imaging studies: A number of tests may be done, including X-rays (including a Panorex, a panoramic dental X-ray), CT scan, MRI, PET scan, and, occasionally, a nuclear medicine 
•  scan of the bones to detect metastatic disease

Mouth and Throat Cancer Treatment

After evaluation by a surgical or radiation oncologist to treat the cancer, there will be ample opportunity to ask questions and discuss which treatments are available.

• The doctor will explain each type of treatment, elaborate the pros and cons, and make recommendations.
• Treatment for head and neck cancer depends on the type of cancer and whether it has affected other parts of the body. Factors such as age, overall health, and whether the patient has already been treated for the cancer before are included in the treatment decision-making process.
• The decision of which treatment to pursue is made with the doctor (with input from other members of the care team) and family members, but ultimately, the decision is the patient's.
• A patient should be certain to understand exactly what will be done and why, and what he or she can expect from the choices. With oral cancers, it is especially important to understand the side effects of treatment.

Like many cancers, head and neck cancer is treated on the basis of cancer stage. The most widely used therapies are surgery and radiation therapy. Chemotherapy is used in some advanced cases. A person's treatment plan will be individualized for his or her specific situation. Targeted therapy refers to the use of drugs or other substances that block the growth and spread of cancer by interfering with molecules specific to the particular type of tumor.

• The medical team may include an ear, nose, and throat surgeon; an oral surgeon; a plastic surgeon; and a specialist in prosthetics of the mouth and jaw (prosthodontist), as well as a specialist in radiation therapy (radiation oncologist) and medical oncology.
• Because cancer treatment can make the mouth sensitive and more likely to be infected, the doctor will probably advise the patient to have any needed dental work done before receiving treatments.
• The team will also include a dietitian to ensure that the patient gets adequate nutrition during and after therapy.
• A speech therapist may be needed to help the patient recover his or her speech or swallowing abilities after treatment.
• A physical therapist may be needed to help the patient recover function compromised by loss of muscle or nerve activity from the surgery.
• A social worker, counselor, or member of the clergy will be available to help the patient and his or her family cope with the emotional, social, and financial toll of your treatment.