Oral Cancer
NIH Publication No. 97-1574 Originally Posted: 9/28/1998 Last Modified: 12/12/2000

Introduction

The National Cancer Institute (NCI) has written this booklet to help people with oral cancer and their families and friends better understand this disease. We hope others will also read it to learn more about oral cancer.

This booklet describes symptoms, diagnosis, and treatment. It also has information about rehabilitation and about sources of support to help patients cope with oral cancer.

Our knowledge about oral cancer keeps increasing. For up-to-date information or to order this publication, call the National Cancer Institute's Cancer Information Service (CIS). The toll-free number is 1-800-4-CANCER (1-800-422-6237).

The CIS uses a National Cancer Institute cancer information database called PDQ and other NCI resources to answer callers' questions. Cancer information specialists can also send information from PDQ and other NCI materials about cancer, its treatment, and living with the disease.

Words that may be new to readers appear in italics. Definitions of these and other terms related to oral cancer can be found in the Dictionary. For some words, a "sounds-like" spelling is also given.

The Oral Cavity

This booklet deals with cancer of the oral cavity (mouth) and the oropharynx (the part of the throat at the back of the mouth). The oral cavity includes many parts: the lips; the lining inside the lips and cheeks, called the buccal mucosa; the teeth; the bottom (floor) of the mouth under the tongue; the front two-thirds of the tongue; the bony top of the mouth (hard palate); the gums; and the small area behind the wisdom teeth. The oropharynx includes the back one-third of the tongue, the soft palate, the tonsils, and the part of the throat behind the mouth. Salivary glands throughout the oral cavity make saliva, which keeps the mouth moist and helps digest food.

What Is Cancer?

Cancer is a group of diseases. It occurs when cells become abnormal and divide without control or order. More than 100 different types of cancer are known.

Like all organs of the body, the mouth and throat are made up of many kinds of cells. Cells normally divide in an orderly way to produce more cells only when the body needs them. This process helps keep the body healthy.

Cells that divide when new cells are not needed form too much tissue. The mass of extra tissue, call a tumor, can be benign or malignant.

• Benign tumors are not cancer. They can usually be removed, and in most cases, they don't grow back. Most important, the cells in benign tumors do not invade other tissues and do not spread to other parts of the body. Benign tumors usually are not a threat to life.

• Malignant tumors are cancer. They can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or the lymphatic system. This is how cancer spreads and forms secondary tumors in other parts of the body. The spread of cancer is called metastasis.

When oral cancer spreads, it usually travels through the lymphatic system. Cancer cells that enter the lymphatic system are carried along by lymph, an almost colorless, watery fluid containing cells that help the body fight infection and disease. Along the lymphatic channels are groups of small, bean-shaped organs called lymph nodes (sometimes called lymph glands). Oral cancer that spreads usually travels to the lymph nodes in the neck. It can also spread to other parts of the body. Cancer that spreads is the same disease and has the same name as the original (primary) cancer.

Early Detection

Regular checkups that include an examination of the entire mouth can detect precancerous conditions or the early stages of oral cancer. Your doctor and dentist should check the tissues in your mouth as part of your routine exams.

Symptoms

Oral cancer usually occurs in people over the age of 45 but can develop at any age. These are some symptoms to watch for:

• A sore on the lip or in the mouth that does not heal;
• A lump on the lip or in the mouth or throat;
• A white or red patch on the gums, tongue, or lining of the mouth;
• Unusual bleeding, pain, or numbness in the mouth;
• A sore throat that does not go away, or a feeling that something is caught in the throat;
• Difficulty or pain with chewing or swallowing;
• Swelling of the jaw that causes dentures to fit poorly or become uncomfortable;
• A change in the voice; and/or
• Pain in the ear.

These symptoms may be caused by cancer or by other, less serious problems. It is important to see a dentist or doctor about any symptoms like these, so that the problem can be diagnosed and treated as early as possible.

Diagnosis and Staging

If an abnormal area has been found in the oral cavity, a biopsy is the only way to know whether it is cancer. Usually, the patient is referred to an oral surgeon or an ear, nose, and throat surgeon, who removes part or all of the lump or abnormal-looking area. A pathologist examines the tissue under a microscope to check for cancer cells.

Almost all oral cancers are squamous cell carcinomas. Squamous cells line the oral cavity.

If the pathologist finds oral cancer, the patient's doctor needs to know the stage, or extent, of the disease in order to plan the best treatment. Staging tests and exams help the doctor find out whether the cancer has spread and what parts of the body are affected.

A patient who needs a biopsy may want to ask the doctor these questions:

• How much tissue will be removed for the biopsy?
• How long will the biopsy take? Will I be awake? Will it hurt?
• How should I care for the biopsy site afterward?
• How soon will I know the results?
• If I do have cancer, who will talk with me about treatment? When?

Staging generally includes dental x-rays and x-rays of the head and chest. The doctor may also want the patient to have a CT (or CAT) scan. A CT scan is a series of x-rays put together by a computer to form detailed pictures of areas inside the body. Ultrasonography is another way to produce pictures of areas in the body. High-frequency sound waves (ultrasound), which cannot be heard by humans, are bounced off organs and tissue. The pattern of echoes produced by these waves creates a picture called a sonogram. Sometimes the doctor asks for MRI (magnetic resonance imaging), a procedure in which pictures are created using a magnet linked to a computer. The doctor also feels the lymph nodes in the neck to check for swelling or other changes. In most cases, the patient will have a complete physical examination before treatment begins.

Treatment

After diagnosis and staging, the doctor develops a treatment plan to fit each patient's needs. Treatment for oral cancer depends on a number of factors. Among these are the location, size, type, and extent of the tumor and the stage of the disease. The doctor also considers the patient's age and general health. Treatment involves surgery, radiation therapy, or, in many cases, a combination of the two. Some patients receive chemotherapy, treatment with anticancer drugs.

For most patients, it is important to have a complete dental exam before cancer treatment begins. Because cancer treatment may make the mouth sensitive and more easily infected, doctors often advise patients to have any needed dental work done before treatment begins.

Most people with cancer want to learn all they can about their disease and their treatment choices so they can take an active part in decisions about their medical and dental care. The doctor is the best person to answer their questions. Also, the patient may want to talk with the doctor about taking part in a research study of new treatment methods. Such studies, called clinical trials, are designed to improve cancer treatment.

Many patients find it useful to make a list of questions before seeing the doctor. Taking notes can make it easier to remember what the doctor says. Some patients also find that it helps to have a family member or friend with them--to take part in the discussion, to take notes, or just to listen.

Before treatment begins, the patient may want to ask the doctor these questions:

• What are my treatment choices? Which do you recommend for me? Why?
• What are the risks and possible side effects of each treatment?
• What are the expected benefits of each kind of treatment?
• What can be done about side effects?
• Would a clinical trial be appropriate for me?

There is a lot to learn about cancer and its treatment. Patients do not need to ask all their questions or understand all the answers at once. They will have many chances to ask the doctor to explain things that are not clear and to ask for more information.

Planning Treatment

Treatment decisions can be complex. Before starting treatment, the patient may want to have another doctor review the diagnosis and treatment plan. A short delay will not reduce the chance that treatment will be successful. There are a number of ways to find a doctor for a second opinion:

• The patient's doctor or dentist may suggest a specialist who treats oral cancer.

• The Cancer Information Service, at 1-800-4-CANCER, can tell callers about cancer centers and other NCI-supported programs in their area.

• Patients can get the names of specialists from their local medical or dental society, a nearby hospital, or a medical or dental school.

• The Directory of Medical Specialists lists doctors' names along with their specialty and their background. This resource is available in most public libraries.

Methods of Treatment

Patients with oral cancer may be treated by a team of specialists. The medical team may include an oral surgeon; an ear, nose, and throat surgeon; a medical oncologist; a radiation oncologist; a prosthodontist; a general dentist; a plastic surgeon; a dietitian; a social worker; a nurse; and a speech therapist.

Surgery to remove the tumor in the mouth is the usual treatment for patients with oral cancer. If there is evidence that the cancer has spread, the surgeon may also remove lymph nodes in the neck. If the disease has spread to muscles and other tissues in the neck, the operation may be more extensive.

Before surgery, the patient may want to ask the doctor these questions:

• What kind of operation will it be?
• How will I feel after the operation? If I have pain, how will you help me?
• Will I have trouble eating?
• Where will the scars be? What will they look like?
• Do you expect that there will be long-term effects from the surgery?
• Will there be permanent changes in my appearance?
• Will I lose my teeth? Can they be replaced? How soon?
• If I need to have plastic surgery, when can that be done?
• Will I need to see a specialist for help with my speech?
• When can I get back to my normal activities?

Radiation therapy (also called radiotherapy) is the use of high-energy rays to damage cancer cells and stop them from growing. Like surgery, radiation therapy is local therapy; it affects only the cells in the treated area. The energy may come from a large machine (external radiation). It can also come from radioactive materials placed directly into or near the tumor (internal radiation). Radiation therapy is sometimes used instead of surgery for small tumors in the mouth. Patients with large tumors may need both surgery and radiation therapy.

Radiation therapy may be given before or after surgery. Before surgery, radiation can shrink the tumor so that it can be removed. Radiation after surgery is used to destroy cancer cells that may remain.

For external radiation therapy, the patient goes to the hospital or clinic each day for treatments. Usually, treatment is given 5 days a week for 5 to 6 weeks. This schedule helps protect healthy tissues by dividing the total amount of radiation into small doses.

Implant radiation therapy puts tiny "seeds" containing radioactive material directly into the tumor or in tissue near it. Generally, an implant is left in place for several days, and the patient will stay in the hospital in a private room. The length of time nurses and other caregivers, as well as visitors, can spend with the patient will be limited. The implant is removed before the patient goes home.

Before radiation therapy, a patient may want to ask the doctor these questions:

• When will the treatments begin? When will they end?
• How will I feel during therapy?
• What can I do to take care of myself during therapy?
• Can I continue my normal activities?
• How will my mouth and face look afterward?
• Will I need a special diet? For how long?
• If my mouth becomes dry, what can I do about it?

Chemotherapy is the use of drugs to kill cancer cells. Researchers are looking for effective drugs or drug combinations to treat oral cancer. They are also exploring ways to combine chemotherapy with other forms of cancer treatment to help destroy the tumor and prevent the disease from spreading.

Clinical Trials

Researchers are developing treatment methods that are more effective against oral cancer, and they are also finding ways to reduce side effects of treatment. When laboratory research shows that a new method has promise, doctors use it to treat cancer patients in clinical trials. These trials are designed to answer scientific questions about the new approach and to find out whether it is both safe and effective. Patients who take part in clinical trials make an important contribution to medical science and may have the first chance to benefit from improved treatment methods.

Clinical trials to study new treatments for oral cancer are under way in hospitals throughout the country. Some trials involve ways to shrink or destroy the primary tumor. In others, scientists are testing ways to prevent the cancer from coming back in the mouth or spreading to other parts of the body. Still others involve treatments to slow or stop cancer that has already spread.

Researchers are studying the timing of treatments and new ways to combine various types of treatment. For example, they are trying to increase the effectiveness of radiation therapy by giving treatments twice a day instead of once a day. They are also working with hyperthermia (heat) and with drugs called radiosensitizers to try to make cancer cells more sensitive to radiation. Researchers are also using drugs to help protect normal cells from radiation damage. In addition, they are exploring various new anticancer drugs and drug combinations.

People who have had oral cancer have an increased risk of getting a new cancer of the mouth or another part of the head or neck. Doctors are trying to find ways to prevent these new cancers. Some research has shown that a substance related to vitamin A may prevent a new cancer from developing in someone who has already been successfully treated for oral cancer.

Oral cancer patients who are interested in taking part in a trial should talk with their doctor. They may want to read Taking Part in Clinical Trials: What Cancer Patients Need To Know, a booklet that explains what treatment studies are and outlines some of their possible benefits and risks.

One way to learn about clinical trials is through PDQ, a computerized resource developed by the National Cancer Institute. PDQ contains information about cancer treatment and an up-to-date list of trials all over the country. The Cancer Information Service, at 1-800-4-CANCER, can provide PDQ information to patients and the public.

Side Effects of Treatment

It is hard to limit the effects of cancer treatment so that only cancer cells are removed or destroyed. Because healthy cells and tissues may also be damaged, treatment often causes side effects.

The side effects of cancer treatment vary. They depend mainly on the type and extent of the treatment and the specific area being treated. Also, each person reacts differently. Some side effects are temporary; others are permanent. Doctors try to plan the patient's therapy to keep side effects to a minimum. They also watch patients very carefully so they can help with any problems that occur.

Surgery to remove a small tumor in the mouth usually does not cause any lasting problems. For a larger tumor, however, the surgeon may need to remove part of the palate, tongue, or jaw. Such surgery is likely to change the patient's ability to chew, swallow, or talk. The patient may also look different.

After surgery, the patient's face may be swollen. This swelling usually goes away within a few weeks. However, removing lymph nodes can slow the flow of lymph, which may collect in the tissues; this swelling may last for a long time.

Before starting radiation therapy, a patient should see a dentist who is familiar with the changes this therapy can cause in the mouth. Radiation therapy can make the mouth sore. It can also cause changes in the saliva and may reduce the amount of saliva, making it hard to chew and swallow. Because saliva normally protects the teeth, mouth dryness can promote tooth decay. Good mouth care can help keep the teeth and gums healthy and can make the patient feel more comfortable. The health care team may suggest the use of a special kind of toothbrush or mouthwash. The dentist usually suggests a special fluoride program to keep the teeth healthy. To help relieve mouth dryness, the health care team may suggest the use of artificial saliva and other methods to keep the mouth moist. Mouth dryness from radiation therapy goes away in some patients, but it can be permanent.

Weight loss can be a serious problem for patients being treated for oral cancer because a sore mouth may make eating difficult. Your doctor may suggest ways to maintain a healthy diet. In many cases, it helps to have food and beverages in very small amounts. Many patients find that eating several small meals and snacks during the day works better than trying to have three large meals. Often, it is easier to eat soft, bland foods that have been moistened with sauces or gravies; thick soups, puddings, and high protein milkshakes are nourishing and easy to swallow. It may be helpful to prepare other foods in a blender. The doctor may also suggest special liquid dietary supplements for patients who have trouble chewing. Drinking lots of fluids helps keep the mouth moist and makes it easier to eat.

Some patients are able to wear their dentures during radiation therapy. Many, however, will not be able to wear dentures for up to a year after treatment. Because the tissues in the mouth that support the denture may change during or after treatment, dentures may no longer fit properly. After treatment is over, a patient may need to have dentures refitted or replaced.

Radiation therapy can also cause sores in the mouth and cracked and peeling lips. These usually heal in the weeks after treatment is completed. Often, good mouth care can help prevent these sores. Dentures should not be worn until the sores have healed.

During radiation therapy, patients may become very tired, especially in the later weeks of treatment. Resting is important, but doctors usually advise their patients to try to stay reasonably active. Patients should match their activities to their energy level. It's common for radiation to cause the skin in the treated area to become red and dry, tender, and itchy. Toward the end of treatment, the skin may become moist and "weepy." There may be permanent darkening or "bronzing" of the skin in the treated area. This area should be exposed to the air as much as possible but should also be protected from the sun. Good skin care is important at this time, but patients should not use any lotions or creams without the doctor's advice. Men may lose all or part of their beard, but facial hair generally grows back after treatment is done. Usually, men shave with an electric razor during treatment to prevent cuts that may lead to infection. Most effects of radiation therapy on the skin are temporary. The area will heal when the treatment is over.

The side effects of chemotherapy depend on the drugs that are given. In general, anticancer drugs affect rapidly growing cells, such as blood cells that fight infection, cells that line the mouth and the digestive tract, and cells in hair follicles. As a result, patients may have side effects such as lower resistance to infection, loss of appetite, nausea, vomiting, or mouth sores. They also may have less energy and may lose their hair.

The side effects of cancer treatment are different for each person, and they may even be different from one treatment to the next. Doctors, nurses, and dietitians can explain the side effects of cancer treatment and can suggest ways to deal with them. The booklets Radiation Therapy and You and Eating Hints for Cancer Patients contain helpful information about cancer treatment and coping with side effects. Patients receiving anticancer drugs will find useful information in Chemotherapy and You.

Rehabilitation

Rehabilitation is a very important part of treatment for patients with oral cancer. The goals of rehabilitation depend on the extent of the disease and the treatment a patient has received. The health care team makes every effort to help the patient return to normal activities as soon as possible. Rehabilitation may include dietary counseling, surgery, a dental prosthesis, speech therapy, and other services.

Sometimes, a patient needs reconstructive and plastic surgery to rebuild the bones or tissues of the mouth. If this is not possible, a prosthodontist may be able to make an artificial dental and/or facial part (prosthesis). Patients may need special training to use the device.

Speech therapy generally begins as soon as possible for a patient who has trouble speaking after treatment. Often, a speech therapist visits the patient in the hospital to plan therapy and teach speech exercises. Speech therapy usually continues after the patient returns home.

Followup Care

Regular followup exams are very important for anyone who has been treated for oral cancer. The physician and the dentist watch the patient closely to check the healing process and to look for signs that the cancer may have returned. Patients with mouth dryness from radiation therapy should have dental exams three times a year.

The patient may need to see a dietitian if weight loss or eating problems continue. Most doctors urge their oral cancer patients to stop using tobacco and alcohol to reduce the risk of developing a new cancer.

Support for Cancer Patients

Living with a serious disease isn't easy. Cancer patients and those who care about them face many problems and challenges. Finding the strength to cope with these difficulties is easier when people have helpful information and support services. Several useful booklets, including Taking Time: Support for People With Cancer and the People Who Care About Them, are available from the Cancer Information Service.

Cancer patients may worry about holding a job, caring for their family, or starting new relationships. Worries about tests, treatments, hospital stays, and medical bills are common. Doctors, nurses, and other members of the health care team can help calm fears and ease confusion about treatment, working, or daily activities. Also, meeting with a nurse, social worker, counselor, or member of the clergy can be helpful for patients who want to talk about their feelings or discuss their concerns.

Friends and relatives, especially those who have had personal experience with cancer, can be very supportive. Also, many patients find it helpful to discuss their concerns with others who are facing similar problems. Cancer patients often get together in support groups, where they can share what they have learned about cancer and its treatment and about coping with the disease. It is important to keep in mind, however, that each patient is different. Treatments and ways of dealing with cancer that work for one person may not be right for another--even if they both have the same kind of cancer. It is always a good idea to discuss the advice of friends and family members with the doctor.

Often, a social worker at the hospital or clinic can suggest groups that can help with rehabilitation, emotional support, financial aid, transportation, or home care.

What the Future Holds

Patients and their families are naturally concerned about what the future holds. Sometimes they use statistics to try to figure out whether the patient will be cured or how long he or she will live. It is important to remember, however, that statistics are averages based on large numbers of patients. They cannot be used to predict what will happen to a certain patient because no two cancer patients are alike. The doctor who takes care of the patient knows his or her medical history and is in the best position to discuss the person's outlook (prognosis).

People should feel free to ask the doctor about their chance of recovery, but not even the doctor knows for sure what will happen. When doctors talk about surviving cancer, they may use the term remission rather than cure. Even though many patients with oral cancer recover completely, doctors use this term because oral cancer can recur.

Causes and Prevention

Scientists at hospitals and medical centers all across the country are studying this disease to learn more about what causes it and how to prevent it. Doctors do know that no one can "catch" cancer from another person: it is not contagious. Two known causes of oral cancer are tobacco and alcohol use.

Tobacco use--smoking cigarettes, cigars, or pipes; chewing tobacco; or dipping snuff--accounts for 80 to 90 percent of oral cancers. A number of studies have shown that cigar and pipe smokers have the same risk as cigarette smokers. Studies indicate that smokeless tobacco users are at particular risk of developing oral cancer. For long-time users, the risk is much greater, making the use of snuff or chewing tobacco among young people a special concern.

People who stop using tobacco--even after many years of use--can greatly reduce their risk of oral cancer. Special counseling or self-help groups may be useful for those who are trying to give up tobacco. Some hospitals have groups for people who want to quit. Also, the Cancer Information Service and the American Cancer Society may have information about groups in local areas to help people quit using tobacco.

Chronic and/or heavy use of alcohol also increases the risk of oral cancer, even for people who do not use tobacco. However, people who use both alcohol and tobacco have an especially high risk of oral cancer. Scientists believe that these substances increase each other's harmful effects.

Cancer of the lip can be caused by exposure to the sun. The risk can be avoided with the use of a lotion or lip balm containing a sunscreen. Wearing a hat with a brim can also block the sun's harmful rays. Pipe smokers are especially prone to cancer of the lip.

Some studies have shown that many people who develop oral cancer have a history of leukoplakia, a whitish patch inside the mouth. The causes of leukoplakia are not well understood, but it is commonly associated with heavy use of tobacco and alcohol. The condition often occurs in irritated areas, such as the gums and mouth lining of smokeless tobacco users and the lower lip of pipe smokers.

Another condition, erythroplakia, appears as a red patch in the mouth. Erythroplakia occurs most often in people 60 to 70 years of age. Early diagnosis and treatment of leukoplakia and erythroplakia are important because cancer may develop in these patches.

People who think they might be at risk for developing oral cancer should discuss this concern with their doctor or dentist, who may be able to suggest ways to reduce the risk and plan an appropriate schedule for checkups.

Another Federal Resource: National Institute of Dental Research
Building 31, Room 2C35
9000 Rockville Pike
Bethesda, MD 20892

The National Institute of Dental Research, an agency of the Federal Government, is concerned with the causes, prevention, diagnosis, and treatment of oral and dental diseases. It can supply free printed material about oral health during and after cancer treatment.

Other Booklets

The NCI booklets listed below are available free of charge by calling the Cancer Information Service at 1-800-4-CANCER.

Booklets About Cancer Treatment

• Radiation Therapy and You: A Guide to Self-Help During Treatment
• Chemotherapy and You: A Guide to Self-Help During Treatment
• Eating Hints for Cancer Patients
• Helping Yourself During Chemotherapy: 4 Steps for Cancer Patients
• Taking Part in Clinical Trials: What Cancer Patients Need To Know
• Pain Control: A Guide for People with Cancer and Their Families
• Get Relief from Cancer Pain

Booklets About Living With Cancer

• Taking Time: Support for People With Cancer and the People Who Care About Them
• Facing Forward: A Guide for Cancer Survivors
• When Cancer Recurs: Meeting the Challenge Again
• Advanced Cancer: Living Each Day

National Cancer Institute Information Resources

You may want more information for yourself, your family, and your health care provider. The following National Cancer Institute (NCI) services are available to help you.

Telephone
Cancer Information Service (CIS)
Provides accurate, up-to-date information on cancer to patients and their families, health professionals, and the general public. Information specialists translate the latest scientific information into understandable language and respond in English, Spanish, or on TTY equipment.

Toll-free: 1-800-4-CANCER (1-800-422-6237)

TTY (for deaf and hard of hearing callers): 1-800-332-8615

Internet

These Web sites may be useful:

http://cancer.gov		NCI's primary Web site; contains information about the Institute and its programs.
http://cancertrials.nci.nih.gov		cancerTrials™; NCI's comprehensive clinical trials information center for patients, health professionals, and the public. Includes information on understanding trials, deciding whether to participate in trials, finding specific trials, plus research news and other resources.
http://cancernet.nci.nih.gov		CancerNet™; contains material for health professionals, patients, and the public, including information from PDQ® about cancer treatment, screening, prevention, supportive care, genetics, and clinical trials; CANCERLIT®, a bibliographic database; and a dictionary with medical terms related to cancer.

E-mail
CancerMail
Includes NCI information about cancer treatment, screening, prevention, and supportive care. To obtain a contents list, send e-mail to cancermail@icicc.nci.nih.gov with the word "help" in the body of the message.

Fax
CancerFax^®
Includes NCI information about cancer treatment, screening, prevention, and supportive care. To obtain a contents list, dial 1-800-624-2511 or 301-402-5874 from your touch tone phone or fax machine hand set and follow the recorded instructions.

Dictionary

benign (beh-NINE): Not cancerous; does not invade nearby tissue or spread to other parts of the body.

biopsy (BY-ahp-see): The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire tumor or lesion is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.

buccal mucosa (BUK-ul myoo-KO-sa): The inner lining of the cheeks and lips.

cancer: A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.

chemotherapy (kee-mo-THER-a-pee): Treatment with anticancer drugs.

clinical trial: A research study that tests how well new medical treatments or other interventions work in people. Each study is designed to test new methods of screening, prevention, diagnosis, or treatment of a disease.

CT scan: Computed tomography scan. A series of detailed pictures of areas inside the body, taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized tomography and computerized axial tomography (CAT) scan.

digestive tract (dye-JES-tiv): The organs through which food passes when food is eaten. These organs are the mouth, esophagus, stomach, small and large intestines, and rectum.

erythroplakia (eh-RITH-ro-PLAY-kee-a): A reddened patch with a velvety surface found in the mouth.

external radiation (ray-dee-AY-shun): Radiation therapy that uses a machine to aim high-energy rays at the cancer. Also called external-beam radiation.

hair follicles (FOL-i-kuls): Shafts or openings on the surface of the skin through which hair grows.

hyperthermia (hye-per-THER-mee-a): A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs.

internal radiation (ray-dee-AY-shun): A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near the tumor. Also called brachytherapy, implant radiation, or interstitial radiation therapy.

leukoplakia (loo-ko-PLAY-kee-a): A white patch that may develop on mucous membranes such as the cheek, gums, or tongue and may become cancerous.

local therapy: Treatment that affects cells in the tumor and the area close to it.

lymph (limf): The almost colorless fluid that travels through the lymphatic system and carries cells that help fight infection and disease.

lymph node: A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Also known as a lymph gland. Lymph nodes are spread out along lymphatic vessels and contain many lymphocytes, which filter the lymphatic fluid (lymph).

lymphatic system (lim-FAT-ik): The tissues and organs that produce, store, and carry white blood cells that fight infection and other diseases. This system includes the bone marrow, spleen, thymus, and lymph nodes and a network of thin tubes that carry lymph and white blood cells. These tubes branch, like blood vessels, into all the tissues of the body.

malignant (ma-LIG-nant): Cancerous; a growth with a tendency to invade and destroy nearby tissue and spread to other parts of the body.

medical oncologist (on-KOL-o-jist): A doctor who specializes in diagnosing and treating cancer using chemotherapy, hormonal therapy, and biological therapy. A medical oncologist often serves as the main caretaker of someone who has cancer and coordinates treatment provided by other specialists.

metastasis (meh-TAS-ta-sis): The spread of cancer from one part of the body to another. Tumors formed from cells that have spread are called "secondary tumors" and contain cells that are like those in the original (primary) tumor. The plural is metastases.

MRI: Magnetic resonance imaging (mag-NET-ik REZ-o- nans IM-a-jing). A procedure in which a magnet linked to a computer is used to create detailed pictures of areas inside the body. Also called nuclear magnetic resonance imaging (NMRI).

oral surgeon: A dentist with special training in surgery of the mouth and jaw.

oropharynx (or-o-FAIR-inks): The middle part of the throat that includes the soft palate, the base of the tongue, and the tonsils.

palate (PAL-et): The roof of the mouth. The front portion is bony (hard palate), and the back portion is muscular (soft palate).

pathologist (pa-THOL-o-jist): A doctor who identifies diseases by studying cells and tissues under a microscope.

plastic surgeon: A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases.

precancerous (pre-KAN-ser-us): A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.

prognosis (prog-NO-sis): The likely outcome or course of a disease; the chance of recovery or recurrence.

prosthesis (pros-THEE-sis): An artificial replacement of a part of the body.

prosthodontist (pros-tho-DON-tist): A dentist with special training in making replacements for missing teeth or other structures of the oral cavity to restore an individual's appearance, comfort, or health.

radiation oncologist (ray-dee-AY-shun on-KOL-o-jist): A doctor who specializes in using radiation to treat cancer.

radiation therapy (ray-dee-AY-shun): The use of high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from materials called radioisotopes. Radioisotopes produce radiation and can be placed in or near the tumor or in the area near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation, interstitial radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Also called radiotherapy.

radiosensitizers: Drugs that make tumor cells more sensitive to radiation.

recur: To occur again. Recurrence is the return of cancer, at the same site as the original (primary) tumor or in another location, after the tumor had disappeared.

remission: A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although there still may be cancer in the body.

salivary glands (SAL-ih-vair-ee): Glands in the mouth that produce saliva.

squamous cell carcinoma (SKWAY-mus. . .kar-sin-O-ma): Cancer that begins in squamous cells, which are thin, flat cells resembling fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.

staging: Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body.

surgery: A procedure to remove or repair a part of the body or to find out whether disease is present.

tissue (TISH-oo): A group or layer of cells that are alike in type and work together to perform a specific function.

tonsils: Small masses of lymphoid tissue on either side of the throat.