Radiation Therapy for Nasopharyngeal Cancer

Since these cancers are not common in the US and are located near many critical structures in your head and neck, it’s very important to go to a cancer center and radiation oncologist who has experience treating these cancers. This will help coordinate your care between cancer specialists to make a complete treatment plan.

Radiation therapy uses high-energy x-rays or particles to kill cancer cells or slow their rate of growth. Most nasopharyngeal cancers (NPC) are sensitive to radiation, so it's usually part of the initial treatment if the NPC has not spread outside the head and neck region.

Radiation can be used in many ways to treat NPC:

• As the main treatment for cancers that are small and have not spread to lymph nodes in the neck
• As the main treatment with chemotherapy for large cancers or cancers that have spread to the lymph nodes in the neck
• As the main treatment for people who cannot have chemotherapy
• After chemotherapy in patients with NPC that has grown into nearby structures and/or has spread to lymph nodes in the neck. In patients whose tumors respond to chemotherapy, treatment with more chemotherapy plus radiation (chemoradiation) can help some people live longer.
• To help with symptoms, such as pain, bleeding, or trouble swallowing, in people with advanced cancer
• To treat cancer that has come back after treatment (recurrence)

Radiation therapy is usually given both to the main nasopharyngeal tumor and to nearby lymph nodes in the neck. Even if the lymph nodes are not large or abnormal on an imaging test or physical exam, radiation is still used, just in case a few cancer cells have spread there. If the lymph nodes are known to have cancer cells, higher radiation doses are used.

Radiation to this part of your body can cause problems for your teeth and gums, so it's important to see a dentist before starting treatment. A dentist can make sure your mouth is healthy before treatment. They might recommend that certain bad teeth be removed before you start radiation because they can increase your chance of infection. The dentist will probably also recommend using some form of fluoride treatment after completing therapy. During and after treatment your dentist can help check for and treat any problems that might come up, such as infection or tooth and bone damage.

Quit smoking before nasopharyngeal cancer treatment

If you smoke, it is important to quit. Smoking during radiation treatment can cause more side effects and a poor response to radiation, which might raise your risk of the cancer coming back (recurrence).  Smoking after treatment also increases the chance of getting a new cancer. Quitting smoking for good (before treatment starts, if possible) is the best way to improve your chances for successful treatment. It is never too late to quit. For help, see How To Quit Using Tobacco.

External beam radiation therapy (EBRT) for nasopharyngeal cancer

External beam radiation therapy is the most common type of radiation used to treat NPC. This type of radiation uses x-rays that are aimed at the tumor from a large machine outside the body.

Before starting EBRT, a somewhat flexible but sturdy mesh head and neck mask might be made to hold your head, neck, and shoulders in the exact same position for each treatment. Some people might feel a bit confined while this mask is on and might need to ask for medicine to help them relax during the treatment. Sometimes, the mask can be adjusted so that it is not too constricting. Discuss your options with your radiation oncologist. You might also be fitted for a bite block that you will hold in your mouth during treatment.

Radiation therapy is much like getting an x-ray, but the radiation dose is stronger and aimed more precisely at the cancer. The treatment doesn't hurt and the machine doesn't touch you. Each treatment lasts only a few minutes, but the setup time – getting you in place for treatment – often takes longer.

Different types of EBRT

There are advanced EBRT techniques that help doctors focus the radiation more precisely or use different types of radiation, like protons. 

Intensity-modulated radiation therapy (IMRT) is most often used to treat NPC. It is a type of conformal therapy that uses a computer-driven machine that moves around the patient as it delivers radiation. Along with shaping the beams and aiming them at the tumor from several angles, the intensity (strength) of the beams can be adjusted to limit the dose reaching the nearby normal tissues and important structures. This may let the doctor give a higher dose to the tumor and helps reduce side effects.

Proton beam radiation therapy  focuses proton beams on the cancer. Unlike x-rays, which go through the patient and release radiation both before and after they hit the tumor, protons only travel a certain distance, so the tissues behind the tumor may be exposed to less radiation. This is hoped to lessen side effects compared to other types of radiation, such as x-rays. However, that has not yet been shown to be the case in a clinical trial. Because of this, proton therapy is not widely available in the United States and might not be covered by many insurance companies at this time.

Common treatment schedule for EBRT

The standard EBRT schedule for nasopharyngeal cancers is usually daily fractions (doses) 5 days a week for about 6 to 7 weeks.

Brachytherapy (internal radiation)

Brachytherapy is another way to deliver radiation. Very thin metal rods or wires, which carry small pellets of radioactive materials, are placed in or very near the cancer. The radiation travels a very short distance, so it destroys the cancer without causing much harm to nearby healthy tissues.

Brachytherapy is not often used as a first treatment for nasopharyngeal cancer. But it might be used if the cancer recurs (comes back) or does not go away completely with chemoradiation. Sometimes, internal and external beam radiation therapy are used together.

Chemoradiation

Chemoradiation is chemotherapy given at the same time as radiation. It can often work better than radiation alone, but it also tends to have more side effects. (You can find more on this in Chemotherapy for Nasopharyngeal Cancer.)

Possible side effects of radiation therapy for nasopharyngeal cancer

If you are going to get radiation therapy, it’s important to ask your doctor about the possible side effects so you know what to expect.

Common short-term side effects of external beam radiation to the head and neck can include:

• Skin changes in the area where the radiation is directed, with redness or blistering
• Nausea and vomiting
• Fatigue (tiredness)
• Sores in the mouth and throat which can lead to trouble swallowing and weight loss from not eating
• Hoarseness
• Loss of taste

These side effects often get better once radiation has stopped.

Long-lasting or permanent side effects of radiation therapy

Other side effects might not get better over time, such as damage to the bones of the skull, or problems with hearing or vision because of damage to certain nerves. Other long-term side effects might include:

• Tooth problems: Radiation to these areas can make any tooth problems that you already have worse and hard to fix. Most doctors will suggest you get your teeth checked by a dentist before starting radiation therapy to the head or neck area. In some cases, the dentist may even advise removing some teeth before treatment to lessen the chance that you'll have problems later, such as an infection.
• Dry mouth: This is a major concern with radiation therapy for NPC. Damage to the salivary glands can cause dry mouth that doesn't go away and makes it hard to swallow food. Dry mouth can also lead to severe tooth decay. To help prevent dental problems, people treated with radiation to the head or neck area need to practice careful oral hygiene and see the dentist regularly. Dry mouth is less of a problem if IMRT is used.
• Thyroid problems: The thyroid gland is often damaged if the neck area is treated with EBRT. The damage doesn’t cause problems that are noticed right away, so your doctor will watch your thyroid function with blood tests in the years after treatment. If your thyroid function goes down, pills to replace thyroid hormone may be needed.
• Damage to the pituitary gland: The pituitary gland controls many hormones in the body. Blood tests can be used to find abnormal hormone levels if the pituitary is damaged by radiation treatment. If the damage is serious enough, it might require taking certain hormones to replace the ones that are missing.
• Damage to the carotid arteries: These are major blood vessels in the neck that carry blood to the brain. They can sometimes become narrowed after radiation. This could raise a person’s risk of stroke or other problems, but it usually takes several years to occur.