Radiation Therapy for Oral Cavity and Oropharyngeal Cancer

Depending on the stage of the oral cavity or oropharyngeal cancer and other factors, radiation therapy might be used as the main treatment, in combination with other treatments, or to help with symptoms.

Radiation therapy uses high-energy x-rays or particles to destroy cancer cells or slow their growth.

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When is radiation therapy used to treat oral cavity and oropharyngeal cancers?
What type of radiation therapy is used?
Seeing a dentist before radiation treatment
Possible side effects
More information about radiation therapy

Because these cancers are located near many critical structures in your head and neck, it’s very important to go to a cancer center that has experience treating them.

When is radiation therapy used to treat oral cavity and oropharyngeal cancers?

Depending on the stage of the cancer and other factors, radiation therapy might be used:

As the main treatment for cancers that are small and have not spread to lymph nodes in the neck, or for people who can’t have chemotherapy.
After surgery (adjuvant therapy), either alone or with chemotherapy (chemoradiation), to try to kill any cancer cells that might have been left behind because they were too small to be seen with the naked eye during surgery. Radiation after surgery can also help lower the chance the cancer will come back in the same spot.
Before surgery (neoadjuvant therapy) with chemotherapy (chemoradiation) or after chemotherapy to try to shrink some larger cancers. In some cases, this might make it possible to use less extensive surgery and remove less tissue.
With a targeted drug for larger cancers, if chemotherapy isn’t an option.
To help with symptoms of advanced cancer, such as pain, bleeding, or trouble swallowing.
To treat cancer recurrence (cancer that comes back after treatment).

What type of radiation therapy is used?

External beam radiation therapy is the most common type of radiation used to treat oral cavity and oropharyngeal cancers. Intraoperative radiation therapy (IORT) and brachytherapy may also be used in some situations.

External beam radiation (EBRT)

EBRT uses x-rays aimed at the tumor from a large machine outside your body.

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 it often takes longer to set up and get you in place for each treatment.

Before you start 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 isn’t 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.

Common treatment schedules for EBRT

Standard EBRT for oral cavity or oropharyngeal cancers is usually given in daily doses, called fractions, 5 days a week for about 7 weeks. Sometimes other schedules might be used:

Hyperfractionation radiation is a slightly lower radiation dose given more than once a day. For example, it might be given twice a day for 7 weeks.
Accelerated fractionation radiation is the standard dose of radiation given each day but over a shorter time (5 to 6 weeks) instead of the usual 7 weeks. For example, it might be given 6 days a week over 5 weeks instead of the standard 5 days a week for 7 weeks.
Hypofractionation radiation is a slightly higher radiation dose given each day to lessen the number of treatments. For example, a higher radiation dose might be given each day for 6 weeks, not the standard 7 weeks.

Hyperfractionation and accelerated fractionation schedules may reduce the risk of cancer coming back in or near the place it started (local recurrence) and might help some people live longer compared to standard EBRT. The drawback is that treatments given on these schedules also tend to have more severe side effects.

Types of EBRT used for oral cavity or oropharyngeal cancers

There are several advanced EBRT techniques that help doctors focus the radiation more precisely. Intensity-modulated radiation therapy (IMRT) is the most common of these techniques used to treat oral cavity and oropharyngeal cancers.

IMRT uses a computer-controlled machine that moves around your body to send radiation from many directions.

The shape and strength of the radiation beams can be adjusted to focus on the tumor while protecting healthy tissues nearby. This allows doctors to give a stronger dose to the cancer while also reducing side effects.

VMAT is a more advanced form of IMRT in which the machine moves in a continuous circle around your body while giving radiation. At the same time, the beam strength and shape are constantly adjusted, making treatment more accurate, faster, and more comfortable.

Proton beam therapy focuses proton beams on the cancer. Unlike x-rays, which go through your body 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.

SBRT may be used in certain cases, especially when the cancer comes back after earlier treatment. It works best for people with small tumors and no skin involvement.

SBRT uses special imaging and computer guidance to aim strong radiation directly at the tumor while protecting nearby healthy tissues such as the brain, eyes, and nerves. It is usually given in only a few sessions instead of many weeks. SBRT can be a helpful option for carefully selected patients.

Intraoperative radiation therapy (IORT)

In rare cases, intraoperative radiation therapy (IORT) may be used to treat oral cavity and oropharyngeal cancers, usually at large hospitals with special experience.

IORT is given during surgery. After the doctor removes as much of the tumor as possible, a strong, focused dose of radiation is delivered directly to the area where the cancer was removed. This treatment may be followed by regular external radiation to help kill any remaining cancer cells.

Doctors carefully choose who can receive this treatment. It works best for people who are in good overall health, had radiation more than 2 years ago, had surgery to remove most of the cancer first, and do not have major organ problems, such as needing a feeding tube or having serious breathing or swallowing issues.

Because this treatment is complex, it is only used in special cases and for carefully selected patients.

Brachytherapy

Brachytherapy is another way to deliver radiation. You might also hear this called internal 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 oral cavity or oropharyngeal cancers. It might be used if the cancer comes back after initial treatment. Sometimes, internal and external beam radiation therapy are used together.

Seeing a dentist before radiation treatment

Radiation to this part of your body can cause problems for your teeth and gums. Before you start treatment, it's important to see a dentist to make sure your mouth is healthy.

The dentist might recommend removing certain bad teeth 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 radiation.

During and after treatment, your dentist can help check for and address any problems that might come up, such as infection or tooth and bone damage.

Possible side effects

Before you begin radiation therapy for oral cavity or oropharyngeal cancer, it’s important to ask your cancer care team about the possible side effects so you know what to expect.

Common short-term side effects

Radiation to the mouth and throat area can cause several short-term side effects, depending on where the radiation is aimed:

Skin changes like a sunburn or suntan in the treated area
Hoarseness
Loss of taste
Redness, soreness, or pain in the mouth and throat
Dry mouth
Trouble swallowing
Fatigue (extreme tiredness)
Open sores in the mouth and throat

Long-lasting or permanent side effects

Some side effects might not get better over time, such as:

Many people treated with radiation to the oral cavity and throat area have painful sores in the mouth and throat that can make it very hard to eat and drink. This can lead to weight loss and poor nutrition.

The sores heal with time after the radiation ends, but some people continue to have problems swallowing long after treatment is finished because of the tightening of the muscles caused by radiation.

Ask your speech pathologist about swallowing exercises you can do to help keep those muscles working and increase your chance of eating normally after treatment.

You might need liquid feeding through a tube placed into your stomach. See Surgery for Oral Cavity and Oropharyngeal Cancer for more on feeding tubes.

Damage to the salivary (spit) glands from radiation can cause a dry mouth that doesn't get better with time. This can lead to discomfort and problems eating and swallowing, as well as damage to the jawbone.

The lack of saliva can also lead to tooth decay (cavities). To help prevent dental problems, people treated with radiation to the mouth or neck need to practice careful oral hygiene and see the dentist regularly. Fluoride treatments may also help.

This can be a serious side effect of radiation treatment. It is more common after tooth infection, extraction, or trauma, and it can be hard to treat. The main symptom is pain in the jaw. In some cases, the bone breaks. Sometimes the fractured bone heals by itself, but often the damaged bone will have to be repaired with surgery.

To help prevent this problem, people getting radiation to the mouth or throat area need to see a dentist to have any problems with their teeth treated before starting radiation. In some cases, teeth may need to be removed.

Radiation might damage your thyroid gland. Your health care team will do blood tests regularly to see how well your thyroid is working. You might need treatment if it's been damaged and isn’t working well.

Some people treated with radiation therapy might be at risk of developing lymphedema in the head and neck areas that were treated. These areas can become swollen and firm. This can be worse if you also had surgery. Medicines, physical therapy, or massage therapy might sometimes be helpful.

These are major blood vessels in your neck that carry blood to your brain. They can sometimes become narrowed after radiation. This could raise the risk of stroke or other problems, but it usually takes several years to occur.

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.

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References

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Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).

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Last Revised: March 23, 2026

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