Radiation Therapy for Nasopharyngeal Cancer

Radiation therapy uses high-energy x-rays or particles to kill cancer cells or slow their rate of growth. It's usually at least part of the main treatment for nasopharyngeal cancer (NPC) because most of these cancers are very sensitive to radiation.

For many cases of NPC, chemotherapy is given along with radiation to try to increase its effects. This treatment, known as chemoradiation, can 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.)

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 abnormally firm or large, 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.

Types of radiation therapy used to treat NPC

External beam radiation therapy (EBRT)

This type of radiation therapy uses x-rays that are aimed at the tumor from a large machine. It's the most common form of radiation therapy for NPC.

Before your treatments start, the radiation team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. Radiation therapy is much like getting an x-ray, but the radiation is stronger. It 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 – takes longer. Most often, radiation treatments are given 5 days a week for about 7 weeks.

EBRT is most often given using a technique called intensity-modulated radiation therapy (IMRT). IMRT focuses the radiation better and lowers the radiation exposure to nearby healthy tissues. This helps reduce side effects.

Stereotactic radiosurgery is a type of radiation treatment that sends a large, precise radiation dose to the tumor area in a single session. (There's no actual surgery involved in this treatment.) The machines used to deliver this type of radiation are known as a Gamma Knife, X-Knife, CyberKnife, and Clinac.

Brachytherapy (internal radiation)

Though seldom used , another way to deliver radiation is to insert (implant) very thin metal rods or wires into or very near the cancer. Small pellets of radioactive materials are then placed into the rods or wires. The radiation travels a very short distance, so it affects the cancer without causing much harm to nearby healthy tissues.

The implant is usually left in place for several days while you stay in a private hospital room. The length of time that visitors, nurses, and other caregivers can spend with you may be limited because of potential radiation exposure, but this depends on the type of radiation. The implant is removed before you go home.

Brachytherapy may be used if the cancer comes back after EBRT (although stereotactic radiosurgery may be used instead). Sometimes, internal and external beam radiation therapy are used together.

Possible side effects of radiation therapy

Common side effects of external beam radiation to the head and neck include:

  • Skin changes in the area where the radiation passes through, 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 get better once radiation has stopped. Other side effects may 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 have 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.
  • Damage to the salivary glands: This is a major concern with radiation therapy for NPC. This damage 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. Dry mouth is less of a problem if IMRT is used. Some of the damage to the salivary glands may also be lessened if a drug called amifostine (Ethyol®) is given before each radiation treatment. This drug can have bothersome side effects, though.
  • Damage to the thyroid gland: 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 is responsible for controlling many hormones in the body. Damage from radiation treatment can be found with blood tests. If the damage is serious enough, this 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. This usually takes several years to occur.

It's important to discuss the possible side effects of radiation therapy with your doctor before starting treatment. Also be sure everything is being done to try to limit these side effects as much as possible.

More information about radiation therapy

To learn more about how radiation is used to treat cancer, see Radiation Therapy.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Amerian Society of Clinical Oncology. Nasopharyngeal Cancer: Treatment Options. 07/2017. Accessed at www.cancer.net/cancer-types/nasopharyngeal-cancer/treatment-options on April 23, 2018.

National Cancer Institute. Nasopharyngeal Cancer Treatment (Adult) (PDQ®)–Patient Version. March 1, 2018. Accessed at www.cancer.gov/types/head-and-neck/patient/adult/nasopharyngeal-treatment-pdq on April 23, 2018.

National Comprehensive Cancer Network, Clinical Practice Guidelines in Oncology (NCCN Guidelines®), Head and Neck Cancers, Version I.2018 -- February 15, 2018. Accessed at www.nccn.org/professionals/physician_gls/pdf/head-and-neck.pdf on April 23, 2018.

Last Revised: September 24, 2018

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