Nasopharyngeal carcinoma
From MayoClinic.com Special to CNN.com

Introduction

 

Nasopharyngeal carcinoma is cancer that occurs in the nasopharynx, which is located behind the nose and above the back of the throat. The nasopharynx is the upper portion of the pharynx — a 5-inch tube that extends from behind the nose to the top of the windpipe and esophagus in your neck.

Nasopharyngeal carcinoma is rare in the United States, comprising only 2 percent of all head and neck cancers. About 2,000 people are diagnosed with nasopharyngeal carcinoma every year in the United States. In other parts of the world — specifically Southeast Asia and northern Africa — nasopharyngeal carcinoma occurs much more frequently.

Men are more likely than women to develop nasopharyngeal carcinoma. It's most commonly diagnosed in people from age 30 to age 60, though nasopharyngeal carcinoma can also occur in older adults and in children.

Nasopharyngeal carcinoma causes signs and symptoms that may suggest a variety of diseases and conditions. That fact, combined with the hidden location of the nasopharynx, means most people aren't diagnosed with nasopharyngeal carcinoma until the cancer has spread. Unfortunately, as nasopharyngeal carcinoma becomes more advanced, it also becomes more difficult to treat.

 

Signs and symptoms

 

Signs and symptoms of nasopharyngeal carcinoma may include:

 

Causes

 

All cancers begin with one or more genetic mutations that cause cells to grow out of control, invade surrounding structures and eventually spread (metastasize) to other parts of the body. Nasopharyngeal carcinomas begin in the squamous cells that line the surface of the nasopharynx.

In many cases, it isn't clear what causes the gene mutations that lead to nasopharyngeal carcinoma, though risk factors that increase the risk of this cancer have been identified. However, it isn't clear why some people with all the risk factors never develop cancer, while others who have no apparent risk factors do.

 

Risk factors

 

In areas where nasopharyngeal carcinoma is most common, researchers have identified several risk factors, including:

Nasopharyngeal carcinoma isn't as closely linked to smoking and excessive alcohol use as most other head and neck cancers are.

 

When to seek medical advice

 

Early signs and symptoms of nasopharyngeal carcinoma may not always prompt you to see your doctor. However, if you notice any unusual and persistent changes in your body, such as unusual nasal congestion, that don't seem right to you, see your doctor.

 

Screening and diagnosis

 

Screening
In the United States, routine screening for nasopharyngeal carcinoma isn't done because the disease is rare. But in areas of the world where nasopharyngeal carcinoma is much more common, for instance in southern China, doctors may offer screenings to people thought to be at high risk of the disease. Screenings may include blood tests to determine whether a person carries the Epstein-Barr virus or careful examinations of the nasopharynx using a tiny camera attached to the end of a flexible tube (endoscope).

Diagnosis
Diagnosing nasopharyngeal carcinoma usually begins with a general examination. Your doctor will ask questions about your signs and symptoms. He or she may press on your neck to feel for swelling in your lymph nodes. Because early signs and symptoms of nasopharyngeal carcinoma aren't specific to the disease, it's common to be misdiagnosed at first. It may take several months of investigating other avenues before a definitive diagnosis is made.

If nasopharyngeal carcinoma is suspected, your doctor will use an endoscope to see inside your nasopharynx and look for abnormalities. The endoscope may be inserted through your nose or through the opening in the back of your throat that leads up into your nasopharynx. Endoscopy may require local anesthesia.

Your doctor may also use the endoscope or another instrument to take a small tissue sample (biopsy) to be tested for cancer. Beyond diagnosing nasopharyngeal cancer, a biopsy also tells your doctor the type of nasopharyngeal carcinoma you have. Nasopharyngeal carcinoma is divided into three types based on the appearance of the cells when viewed under a microscope. Your doctor factors in your type of nasopharyngeal carcinoma when selecting your treatment.

Staging
Once the diagnosis is confirmed, your doctor orders other tests to determine the extent (stage) of the cancer, such as:

Once your doctor has determined the extent of your cancer, he or she assigns it a stage. The stage is used along with several other factors to determine your treatment plan and your prognosis. The stages of nasopharyngeal carcinoma include:

Staging in various parts of the world may be done on a different scale. For instance, a staging system used in Asia includes a stage V.

 

Complications

 

Nasopharyngeal carcinoma frequently spreads (metastasizes) beyond the nasopharynx. Most people with nasopharyngeal carcinoma have regional metastases, meaning cancer cells from the initial tumor have migrated to nearby areas, such as lymph nodes in the neck. Cancer cells that spread beyond the head and neck (distant metastases) most commonly travel to the bones and bone marrow, lungs and liver.

Nasopharyngeal carcinoma may also cause "paraneoplastic syndromes." In these rare disorders your body's immune system reacts to the presence of cancer by attacking normal cells. Paraneoplastic syndromes may cause high levels of certain white blood cells in your blood, fever, neurologic problems or joint problems. Once your cancer is treated, your doctor may prescribe medications to control your immune system.

 

Treatment

 

You and your doctor work together to devise a treatment plan based on several factors, such as the stage of your cancer, the type of cells involved, your treatment goals and the side effects you're willing to tolerate. Treatment for nasopharyngeal carcinoma usually begins with radiation therapy. While surgery is the mainstay of treatment for many cancers, navigating the nasopharynx with surgical tools is delicate. Nasopharyngeal carcinoma is particularly sensitive to radiation therapy, making it the first line of treatment. Surgery and chemotherapy are used in certain cases.

Radiation
Radiation therapy treats cancer with high-energy beams. Radiation therapy destroys quickly growing cells, including cancer cells, in the area where the beams are focused. During treatment you're positioned on a table and a large machine is maneuvered around you to the precise spot where it can target your cancer. You typically receive radiation treatment five days a week for six or seven weeks. You'll also receive radiation to your neck, even if there's no evidence your cancer has spread beyond your nasopharynx. This reduces the chance that your cancer will spread and the chance that your cancer will recur.

Radiation therapy carries a risk of side effects, including hearing loss, dry mouth, sores in the mouth and throat, and an increased risk of tongue cancer and bone cancer. Your nasopharynx is situated among some delicate organs, such as your brain, spinal cord, thyroid gland, eyes and ears. Your radiation therapy team works to protect these organs, but that can't always be done.

Internal radiation therapy (brachytherapy) is sometimes used in recurrent nasopharyngeal carcinoma. With this treatment, radioactive seeds or wires are positioned in the tumor or very close to it.

Chemotherapy
Chemotherapy uses drugs to treat cancer. Unlike radiation therapy, which is focused on one part of your body, chemotherapy travels throughout your body. Chemotherapy works by attacking quickly growing cells, including cancer cells. Some healthy cells are also killed by chemotherapy, which can cause side effects, including fatigue, hair loss, and nausea and vomiting. Chemotherapy may be used to treat nasopharyngeal carcinoma in three ways:

What chemotherapy drugs you receive and how often will be determined by your doctor. The side effects you're likely to experience will depend on which drugs you receive.

Surgery
Surgery is usually reserved for recurrent nasopharyngeal carcinoma. Surgery to remove cancerous lymph nodes in the neck is the most common surgery for nasopharyngeal carcinoma. Surgery to remove a tumor from the nasopharynx requires surgeons to make an incision in the roof of your mouth in order to access the area.

 

Prevention

 

No sure way exists to prevent nasopharyngeal carcinoma. However, you can take steps to reduce your risk of the disease. For instance, cut back on the amount of salt-cured foods and preserved meats that you eat, or avoid these foods altogether. Chinese people who immigrate to North America and adopt a typical American diet have a reduced risk of nasopharyngeal carcinoma. However, the risk never completely goes away, which indicates that other unknown or uncontrollable risk factors may play a role in developing nasopharyngeal carcinoma.

 

Coping skills

 

Everyone deals with a cancer diagnosis in his or her own way. You might experience shock and fear after your diagnosis. Allow yourself time to grieve. A cancer diagnosis can make you feel as though you have little control, so take steps to empower yourself and control what you can about your health. Try to:

 

July 12, 2006