How is nasopharyngeal cancer diagnosed?
Nasopharyngeal cancer (NPC) is most often diagnosed when a person goes to a doctor because of symptoms such as a lump in the neck. The doctor will take a history, do an exam, and then may refer the patient to a specialist and/or order some tests.
Medical history and physical exam
If you have any signs or symptoms that suggest you might have nasopharyngeal cancer, your doctor will want to get your complete medical history to learn about your symptoms and any possible risk factors, including your family history.
A physical exam will be done to look for signs of NPC or other health problems. During the exam, the doctor will pay special attention to the head and neck area, including the nose, mouth, and throat; the facial muscles, and the lymph nodes in the neck.
If your doctor suspects you may have a tumor or other problem in the nose or throat, he or she may order imaging tests (such as CT or MRI) to look at the head and neck area more closely. Your doctor may also refer you to an otolaryngologist (a doctor specializing in ear, nose, and throat problems, also sometimes called an ENT doctor), who will do a more thorough exam of the nasopharynx. The nasopharynx is a difficult area to examine. Most other kinds of doctors do not have the specialized training or equipment to do a thorough exam of this part of the body.
Exams of the nasopharynx
The nasopharynx is located deep inside the head and is not easily seen, so special techniques are needed to examine this area. There are 2 main types of exams used to look inside the nasopharynx for abnormal growths, bleeding, or other signs of disease. Both types of exams are usually done in the doctor's office.
- For indirect nasopharyngoscopy, the doctor uses special small mirrors and lights placed at the back of your throat to look at the nasopharynx and nearby areas.
- For direct nasopharyngoscopy, the doctor uses a fiber-optic scope known as a nasopharyngoscope (a flexible, lighted, narrow tube inserted through the nose) to look directly at the lining of the nasopharynx. You will have numbing medicine sprayed into your nose before the exam to make it easier. This is the method most often used to carefully examine the nasopharynx.
If a tumor starts under the lining of the nasopharynx (in the tissue called the submucosa), it may not be possible to see it directly on physical exam, which is why imaging tests such as CT scans (see below) may be needed as well.
Symptoms and the results of exams can suggest that a person might have NPC, but the actual diagnosis is made by removing cells from an abnormal area and looking at them under a microscope. This is known as a biopsy. Different types of biopsies may be done, depending on where the abnormal area is.
If a suspicious growth is found in the nasopharynx during an exam, the doctor may remove a biopsy sample with small instruments and the aid of a fiber-optic scope. Often, biopsies of the nasopharynx are done in the operating room as an outpatient procedure. The sample is then sent to a lab, where a doctor called a pathologist looks at it under a microscope. If the biopsy sample contains cancer cells, the pathologist sends back a report describing the type of the cancer.
If the cancer is hidden beneath the surface of the nasopharynx, NPC may not be visible during an exam. If a person has symptoms suggesting NPC but nothing abnormal is seen on exam, the doctor may take several samples of normal-looking tissue, which may be found to contain cancer cells when looked at under the microscope.
Fine needle aspiration (FNA) biopsy
An FNA biopsy may be used if you have a suspicious lump in or near your neck. For this procedure, the doctor uses a thin, hollow needle attached to a syringe to aspirate (withdraw) a few drops of fluid containing cells and tiny fragments of tissue. A local anesthetic (numbing medicine) may be used on the skin where the needle will be inserted. In some cases, no anesthetic is needed.
The doctor places the needle directly into the mass for about 10 seconds and withdraws cells and a few drops of fluid. The cells are then looked at under a microscope to see if they are cancerous.
In patients with an enlarged lymph node in the neck area, an FNA biopsy can help determine if the enlargement is caused by a response to an infection, the spread of cancer from somewhere else (such as the nasopharynx), or a cancer that begins in lymph nodes – called a lymphoma. If the cancer started somewhere else, the FNA biopsy alone might not be able to tell where it started. But if a patient already known to have NPC has enlarged neck lymph nodes, FNA can help determine if the spread of NPC caused the lymph node swelling.
Imaging tests use x-rays, magnetic fields, sound waves, or radioactive particles to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, including to help find a suspicious area that might be cancerous, to learn how far cancer may have spread, and to help determine if treatment has been effective.
If you have been diagnosed with NPC, a plain x-ray of your chest may be done to see if the cancer has spread to your lungs. This is very unlikely unless your cancer is far advanced. This x-ray can be done in any outpatient setting. If the results are normal, you probably don’t have cancer in your lungs.
Computed tomography (CT) scan
The CT scan is an x-ray test that produces detailed cross-sectional images of your body. Instead of taking one x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these into images of slices of the part of your body that is being studied.
Before the pictures are taken, you may get an IV (intravenous) line through which a kind of contrast dye (IV contrast) is injected. This helps better outline structures in your body. You may also be asked to drink 1 to 2 pints of a liquid called oral contrast. This helps outline the intestine so that certain areas are not mistaken for tumors. It may not be needed for CT scans of the nasopharynx.
The injection can cause some flushing (redness and warm feeling). Some people are allergic and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have any allergies or have ever had a reaction to a contrast material used for x-rays.
You need to lie still on a table while the scan is being done. During the test, the table slides in and out of the scanner, a ring-shaped machine that completely surrounds the table. You might feel a bit confined by the ring you have to lie in while the pictures are being taken.
A CT scan of the head and neck can provide information about the size, shape, and position of a tumor and can help find enlarged lymph nodes that might contain cancer. CT scans or MRIs are important in looking for cancer that may have grown into the bones at the base of the skull. This is a common place for nasopharyngeal cancer to grow. CT scans can also be used to look for tumors in other parts of the body.
Magnetic resonance imaging (MRI) scan
Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into very detailed images of parts of the body. A contrast material called gadolinium is often injected into a vein before the scan to better see details.
MRI scans may be a little more uncomfortable than CT scans. They take longer – often up to an hour. You may be asked to lie on a table that slides inside a large tube, which is confining and can upset people with a fear of enclosed spaces. Special, “open” MRI machines can sometimes help with this if needed. The MRI machine makes buzzing and clicking noises that you may find disturbing. Some places will provide earplugs to help block this noise out.
Like CT scans, MRIs can be used to try to determine if the cancer has grown into structures near the nasopharynx. MRIs are a little better than CT scans at showing the soft tissues in the nose and throat, but they’re not quite as good for looking at the bones at the base of the skull, a common place for nasopharyngeal cancer to grow.
Positron emission tomography (PET) scan
For a PET scan, you receive an injection of a form of radioactive sugar (known as fluorodeoxyglucose or FDG). The amount of radioactivity used is very low. Because cancer cells in the body are growing rapidly, they absorb large amounts of the sugar. After about an hour, you are moved onto a table in the PET scanner. You lie on the table for about 30 minutes while a special camera creates a picture of areas of radioactivity in the body. The picture is not finely detailed like a CT or MRI scan, but it provides helpful information about your whole body.
Your doctor may use this test to see if the cancer has spread to your lymph nodes. It can also help give the doctor a better idea of whether an abnormal area on a chest x-ray may be cancer. A PET scan can also be useful if your doctor thinks the cancer may have spread but doesn’t know where.
Some machines are able to do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET with the more detailed appearance of that area on the CT.
Blood tests are not used to diagnose NPC, but they may be done for other reasons, such as to help determine whether the cancer may have spread to other parts of the body.
Routine blood counts and blood chemistry tests
Routine blood tests can help determine a patient’s overall health. These tests can help diagnose malnutrition, anemia (low red blood counts), liver disease, and kidney disease. And they may suggest the possibility of spread of the cancer to the liver or bone, which may prompt further testing.
In people getting chemotherapy, blood tests are important to see if the treatment is damaging the bone marrow (where new blood cells are made), liver, and kidneys.
Epstein-Barr virus (EBV) DNA levels
In some patients, the blood level of EBV DNA may be measured before and after treatment to help show how effective treatment is.
Last Medical Review: 09/23/2013
Last Revised: 09/23/2013