Oropharyngeal cancer

Definition

Oropharyngeal cancer is an uncontrolled growth of cells that begins in the oropharynx, the area at the back of the mouth.

Description

The oropharynx is the passageway at the back of the mouth. It connects the mouth to the esophagus (tube through which food passes) and to the pharynx (the channel for the flow of air into and out of the lungs). It takes its name from the way it ties the oral cavity (hence the oro) to the rest of the pharynx, one part of which extends toward the back of the nose (nasopharynx). The base of the tongue, the soft palate (the soft roof of the mouth, above the base of the tongue) and the tonsils are part of the oropharynx.

If the oropharynx is blocked or injured in any way, the condition presents a threat to life because it interferes with both eating and breathing. Thus, an obstruction caused by oropharyngeal cancer is in itself a problem. Oropharyngeal cancer also contributes to problems with chewing and talking because of the importance of the oropharynx in these activities. If the oropharyngeal cancer spreads to the bone, muscle, and soft tissue in the neck, there is a severe effect on the ability of the neck to support the head. In individuals with oropharyngeal cancer that has spread, surgical options might be limited.

Oropharyngeal cancer usually begins in the squamous cells of the epithelial tissue. The squamous cells are flat, and often layered. The epithelial tissue forms coverings for the surfaces of the body. Skin, for example, has an outer layer of epithelial tissue. Throughout the oropharynx there are some very small salivary glands and one of more of them sometimes becomes the site of tumor growth.

Many times cancer that begins in the oropharynx spreads to the base of the tongue. Oropharyngeal cancer can spread to the muscle and bone in the neck, and also to the soft tissue that fills the space around the muscle and bone.

Demographics

In the United States, about 4, 000 cases of oropharyngeal cancer are diagnosed each year. Most of the cancer is found in people who are more than 50 years old. A history of tobacco or alcohol use, especially heavy use, is typically linked to the diagnosis. Men are three to five times more likely to be diagnosed than women.

Some benign tumors arise in the oropharynx. Although they are benign, many studies suggest the growths indicate the person is at greater risk for a malignant tumor growth in the future.

Causes and symptoms

The cause of oropharyngeal cancer is not known; but the risk factors for oropharyngeal cancer are understood. Two important lifestyle choices increase the chance a person will be diagnosed with cancer of the oropharynx. They are tobacco/ cigarettes and alcohol consumption.

Anything that passes into the lungs or stomach through the nose and mouth, must move through the oropharynx. (Air moves through the nasopharynx to reach the oropharynx.) Long periods of exposure to substances such as tobacco byproducts and alcohol somehow trigger cells to begin uncontrolled growth, cancer. About 90 percent of all cancer of the oropharynx starts in a squamous cell.

Since tobacco and alcohol come into direct contact with the squamous cells of the oropharynx as they move through the cavity, they might change the genetic material (DNA) of cells. If a cell cannot repair damage to DNA, a cancerous growth can begin.

A serious interaction occurs between tobacco and alcohol. Individuals who smoke and drink alcoholic beverages are at much greater risk for oropharyngeal cancer. They have as much as 30 times or 40 times the normal risk. The estimate is difficult to make because not all individuals diagnosed are accurate in the statements they make to physicians about their use of these substances. Patients often say they used less tobacco or less alcohol than they actually did.

Viral infection increases the risk of oropharyngeal cancer. So does reduced immunity, which is a condition that may be caused by viral infection. Individuals with papilloma viruses, which are sexually transmitted, may also be at greater risk. Marijuana seems to be linked with oropharyngeal cancer too. Vitamin A deficiency, or specifically, the absence of the carotene (from fruits and vegetables) that the body uses to make vitamin A, might also be a contributing factor.

Symptoms of oropharyngeal cancer include:

• difficulty swallowing
• difficulty chewing
• change in voice
• loss of weight
• lump in the throat
• lump in the neck

Diagnosis

Cells grow old and flake off regularly from epithelial tissues. The first step in diagnosing oropharyngeal cancer often makes use of the natural process. It is given the name exfoliative cytology . A physician scrapes cells from the part of the oropharynx where a cancer is suspected and smears them on a slide. The cells are then treated with chemicals so they can be studied with a microscope. If they do not appear normal, a biopsy , or a tissue sample from a deeper layer of cells, is taken for examination.

Different sorts of biopsies are used. An incision, or cut, is be made to obtain tissue. Or, a needle with a small diameter is inserted into the neck to obtain cells, especially if there is a lump in the neck.

Computed tomography (CT) and magnetic resonance imaging (MRI) scans are also used. They help determine whether the cancer has spread from the walls of the oropharynx. MRI offers a good way to examine the tonsils and the back of the tongue, which are soft tissues. CT is used as a way of studying the jaw, which is bone.

Many extremely specialized means of determining the condition of the oropharynx have been developed. One of them relies on the same sort of light wave technology that now powers much of the communications world, fiberoptics. A fiber (a bundle of glass fibers, actually) with a very small diameter is inserted in the oropharynx and the area is probed with light that is reflected on mirrors for interpretation. Lighting up the oropharynx with the high intensity, very low heat illumination of fiberoptics, a physician can get a good look at the cavity.

Another special way of getting a good look at the oropharynx involves studying it from within by inserting an endoscope into the oropharynx and then, weaving it through adjacent connecting structures. The structures include the trachea, the bronchi, the larynx and the esophagus. The patient is given an anesthetic, local or general, for this procedure. When several organs are examined at the same time, the procedure is called a panendoscopy. The tool used is generally named for the organ for which it is most closely designed. For example, there is a laryngoscope.

Because oropharyngeal cancer often spreads, bones near the oropharynx must be examined carefully. Some special types of equipment are used. A rotating x ray called panorex provides for close inspection of the jaw.

Oropharyngeal cancer also spreads to the esophagus, so physicians usually examine the esophagus when they diagnose oropharyngeal cancer. To do so, they ask the patient to drink a liquid containing barium, a chemical that can be seen on x rays. Then, they can x ray the esophagus and look for bulges or lumps that indicate cancer there.

Treatment team

Generally, physicians with special training in the organs of the throat take responsibility for the care of a patient with oropharyngeal cancer. They are called otolaryngologists or occasionally by a longer name, otorhinolaryngologists.

In abbreviation, otolaryngologists are usually labeled ENT (for Ear, Nose and Throat) specialists. An ENT specializing in cancer will probably lead the team. Some ENTs have a specialty in surgery. Some have a specialty in oncology. Some have a specialty in both.

Nurses, as well as a nutritionist, speech therapist and social worker will also be part of the team. Depending on the extent of the cancer when diagnosed, some surgery and treatments result in extensive changes in the throat, neck and jaw. The social worker, speech therapist and nutritionist are important in helping the patient cope with the changes caused by surgery and radiation treatment. If there is great alteration to the neck because of surgery, rehabilitation will also be part of the recovery process and a rehabilitation therapist a member of the team.

Clinical staging, treatments, and prognosis

Stage 0 indicates some cells with the potential to grow erratically are discovered. But the cells have not multiplied beyond the surface layer of the epithelial tissue of the oropharynx. Stage I describes a cancer less than approximately 2.5 cm (about one inch in diameter) that has not spread. Stage II describes a bigger cancer, up to about 5 cm (about two inches), that has not spread.

Stage III oropharyngeal cancer is either larger than two inches or has spread to one lymph node. The lymph node is enlarged but not much larger than an inch.

In Stage IV, one or more of several things happens. There is either a spread of cancer to a site near the original site. Or, there is more than one lymph node with cancer. Or, the cancer has spread to other parts of the body, such as the larynx, the trachea, the bronchi, the esophagus, or even more distant points, such as the lungs.

The outlook for recovery from oropharyngeal cancer is better the earlier the stage in which the cancer is diagnosed. For stage I and stage II, surgical removal or radiation therapy of the affected area is sometimes all that is required to halt the cell growth. Decisions about which method to use depend on many factors. The tolerance a patient has for radiation or chemotherapy , and the size of the tumor are crucial to the decision process.

Surgical removal can interfere with speech, eating and breathing. So, if non-surgical treatment is an option, it is a good one to try. The larger the tumor, the more urgent is its removal. Smaller tumors can be treated with radiation, or other methods, such as heat or chemotherapy, in an effort to shrink them before surgery. In some cases, surgery might be avoided. For stage III cancer with lymph node involvement, the lymph nodes with the cancer are also removed.

Chemotherapy might be used at any stage, but it is particularly important for stage IV cancer. In some cases, chemotherapy is used before surgery, just as radiation is, to try to eliminate the cancer without cutting, or at least to make it smaller before it is cut out (excised). After surgery, radiation therapy and chemotherapy are both used to treat patients with stage IV oropharyngeal cancer, sometimes in combination. Treatments vary in Stage IV patients depending on the extent of the spread.

Some tumors are so large they cannot be completely removed by surgery. Often, the most promising treatment option for a person with such a tumor is a clinical trial.

Besides categories, or stages, that indicate how far the disease has progressed, there are many categories that are used to describe the kind, or grade, of tumor. The grades take into account such factors as the density of a tumor. Eventually, physicians hope information about tumor grade will make it possible to match treatment and condition very precisely.

Coping with cancer treatment

The patient should be an active member of the treatment team, listening to information and making decisions about which course of treatment to take. Premier cancer centers encourage such a role.

Prior to surgery, discuss the need for a way to communicate if speech is impaired after surgery. A pad and pencil might be all that are needed for a short interval. If there will be a long period of difficulty, the patient should be ready with other means, including special phone service.

A change in appearance after the removal of part of the oropharynx, whether part of the tongue or soft palate or some other portion, can lead to concerns about body image . Social interaction might suffer. A support group can help. Discussions with a social worker also can be beneficial.

If any part of the oropharynx is removed, speech therapy might be necessary to relearn how to make certain sounds. If the surgery requires the removal of some or all of the tongue, a person's speech will be greatly impaired.

Appetite might be affected before, during and after treatment. Before treatment, the presence of a tumor can interfere with chewing and swallowing food, and food might not seem as appealing as it once did. During treatment, particularly radiation treatment, the treated oropharynx will be sore and eating and breathing will be difficult, or impossible.

In some cases, a patient requires a feeding tube (inserted at the opening of the esophagus, through the mouth), a stomach tube (inserted directly in the stomach, if there is no access to the opening of the esophagus) or a breathing tube (inserted directly in the trachea) for some interval of time. The tubes bypass the normal entryways to the stomach and lungs. Liquid food is put directly into the esophagus or stomach. Air is taken directly into the trachea during breathing. The incision or cut in the trachea is called a tracheotomy and the opening in the neck around the trachea is a tracheostomy. Air that enters the trachea directly is not warmed or moistened, and the dry, cold air in the lungs can lead to respiratory complications. Attachments are now available that are positioned at the opening in the neck and filter and add moisture to the air entering the tracheal tube. Learning how to care for the tracheotomy and tracheostomy, how to keep the openings clean and what to do if the tube pops out, relieves anxiety and improves ease of breathing.

After treatment, a loss of sensation in the part of the oropharynx affected, or a loss of part of the tongue or the jaw, can reduce appetite. A nutritionist can help with supplements for people who experience significant weight loss and who do not have an appetite (anorexia ).

Patients who are dependent on tobacco or alcohol products and want to reduce or eliminate their intake, will have to deal with the psychological effects of substance withdrawal in addition to the side-effects from treatment. A support group for tobacco or alcohol dependence might be considered, and joined before treatment begins.

Clinical trials

There are a number of clinical trials in progress. For example, the better researchers understand the nature of cancer cells, the better they are able to design drugs that attack only cancer cells. Or, in some cases, drugs that make it easier to kill cancer cells have also been designed.

The Cancer Information Service at the National Institutes of Health, Bethesda, Md., offers information about clinical trials that are looking for volunteers. The Service offers a toll-free number at 1-800-422-6237.

Prevention

Avoiding smoking and avoiding drinking alcohol are important in the prevention of oropharyngeal cancer. Including lots of fruits and vegetables in the diet is also an important step to preventing cancer. (Even though the importance of fruits and vegetables is not proven to prevent oropharyngeal cancer, overall fruits and vegetables are demonstrated cancer fighters.) Carotene, which the body uses to make vitamin A, seems to be important in the diet of people who are less likely to be diagnosed with oropharyngeal cancer. Any precaution that is taken to avoid contracting sexually transmitted diseases, such as the use of condoms, also offers protection from oropharyngeal cancer.

Special concerns

Growths sometimes develop in the oropharynx that are not cancerous. The benign tumors can be removed by surgery. They usually do not recur. The surgeon should be able to give a patient an accurate appraisal identifying the noncancerous growth, and whether it is likely to indicate future problems.

Oropharyngeal cancer frequently recurs in patients who have been treated for the condition. Thus, after treatment, patients must be examined monthly for one year. They also must be committed to telling their physician if they notice any changes. By the second year, examinations can be at two-month intervals; and then, three-month intervals by the third year and six-month intervals beyond that.

Mouthwash has been suspected as a cancer-causing agent for oropharyngeal cancer. Studies are not conclusive. One line of reasoning suggests alcohol-based mouth-washes add to the effects of alcohol consumed by heavy drinkers. Alcohol-based mouthwashes can be avoided.

See Also Oral cancer; Nasopharyngeal cancer; Smoking cessation

Resources

BOOKS

Atkinson, Lucy Jo and Nancymarie Fortunato. Chapter 36, "Head and Neck Surgery." Berry & Kohn's Operating Room Technique St. Louis: Mosby, 1996.

ORGANIZATIONS

SPOHNC, Support for People with Oral and Head and Neck Cancer. P.O. Box 53, Locust Valley, NY 11560-0053. 800-377-0928.<http://www.spohnc.org>.

OTHER

"Oral Cavity and Pharyngeal Cancer" Online text. American Cancer Society. Revised 05/22/2000. 5 July 2001. 5 July 2001 <http://www3.cancer.org>.

Diane M. Calabrese

KEY TERMS

Biopsy

—Tissue sample is taken from body for examination.

Bronchi

—Branches of the trachea that distribute air to the air sacs (alveoli) of the lungs.

Computed tomography (CT)

—X rays are aimed at slices of the body (by rotating equipment) and results are assembled with a computer to give a three-dimensional picture of a structure.

Endoscope

—Instrument designed to allow direct visual inspection of body cavities, a sort of microscope in a long access tube.

Fiberoptics

—Cool, refracted (bounced) light passes (bounces) along extremely small diameter glass tubes. (Used to illuminate body cavities, such as the oropharynx, with high intensity, and almost heatless light.)

Larynx

—Commonly known as the voice box, the place between the pharynx and the trachea where the vocal cords are located.

Magnetic resonance imaging (MRI)

—Magnetic fields and radio frequency waves are used to take pictures of the inside of the body.

Salivary glands

—Structures in the mouth that make and release (secrete) saliva that helps with digestion.

Tonsils

—Lymph nodes in the throat that are partly encapsulated (enclosed). They are components of the lymphatic system that functions in immunity and removes the excess fluid around cells and returns it to cells.

Trachea

—Tube ringed with cartilage that connects the larynx with the bronchi.

QUESTIONS TO ASK THE DOCTOR

• In which stage is the cancer?
• What is the outlook for a patient with my profile?
• What are the side effects of the treatments that are recommended? Which treatment gives the best combination of survival and quality of life?
• Is there a clinical trial for which I am eligible?