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Radiation Therapy for Mouth Cancer

Memorial Sloan Kettering radiation oncologist Nancy Lee

Radiation therapy for mouth cancer involves sending high-energy beams of particles (usually photons or protons) through the skin toward the tumor. When the beams reach the tumor, they destroy the cancer cells by damaging their DNA. Radiation therapy is known for its particular effectiveness against head and neck tumors, including cancers of the mouth.

Radiation therapy can be used in one of several ways for mouth cancers. It may be recommended after surgery to prevent the cancer’s regrowth. Radiation may also be used as the sole treatment if the tumor cannot be removed surgically or if the tumor regrows after surgery.

Why Choose Memorial Sloan Kettering for Mouth Cancer Radiation Therapy

  • MSK’s radiation therapy team has special training in caring for people with mouth cancer and works closely with the other members of your care team.
  • MSK is the only center to offer weekly MRI imaging at no cost to patients. This mapping allows your radiation oncologist to optimize your radiation plan in real time.
  • You may be eligible to participate in clinical trials exploring new ways to boost the effectiveness of your treatment.

Types of Radiation Therapy for Mouth Cancer

There are many ways to treat mouth cancer with radiation. MSK’s radiation oncologists specialize in head and neck cancers. They have extensive knowledge in knowing which approach will provide you with the most benefit.

MSK’s radiation therapy team has access to every modern form of radiation available. They will customize a treatment plan so precise that it factors in the size and shape of your tumor to the millimeter. Your team’s goal is twofold: to eliminate tumor cells and to prevent the side effects of treatment by keeping the healthy cells around the tumor safe.

Here you will find more in-depth information about the different approaches to mouth cancer radiation therapy.

Intensity-Modulated Radiation Therapy (IMRT)

Intensity-modulated radiation therapy combines the use of a highly advanced computer program with a metal device called a collimator. These tools allow your care team to shape the radiation beams to the exact dimensions of the treatment area.

Prior to the start of radiation therapy, a team of experts, including radiation oncologists and experienced medical physicists, collects detailed information about the treatment area. This includes:

  • a CT scan to map the tumor in 3-D
  • PET, CT, and MRI scans to generate an outline of the tumor

Your team then uses this information along with sophisticated treatment-planning software to calculate the optimal number of radiation beams and the exact angles of those beams. During treatment, the collimator is adjusted to produce the beams at the angles specified by the computer program.

This approach allows us to deliver more precise doses of radiation to the tumor while reducing the risk that healthy tissue is exposed.

Image-Guided Radiation Therapy (IGRT)

Image-guided radiation therapy uses imaging tests (CT, MRI, or PET) and special computer software to optimize the real-time delivery of radiation to the treatment area.

In this approach, daily imaging scans are performed to ensure an accurate position when the dose of radiation is delivered. The imaging scans are processed by special software to map changes in the tumor’s size or location. Your radiation therapy team can use this information to improve the accuracy of the radiation treatments while you are receiving them.

Adaptive Radiotherapy

In conventional radiation treatment planning, a team of radiation oncologists, radiation therapists, medical physicists, and dosimetrists works together to formulate your plan of care. Your team then carries out that plan during your course of treatment, which typically lasts six to seven weeks. Adaptive radiotherapy simply means that we repeat the planning process throughout treatment. Every time we detect certain changes that could affect the precision of the radiation, such as weight loss or tumor shrinkage, we review your treatment plan.

This personalized approach allows us to continually optimize your care while sparing healthy tissue. It is particularly beneficial for people who did not have surgery to remove a tumor.


Brachytherapy involves the placement of radioactive material in the body. The material is sealed inside a seed, pellet, wire, or capsule using a needle or catheter. The radiation given off by this source damages the DNA of nearby cancer cells. Brachytherapy is most commonly used for mouth cancer that has come back after prior treatment. Your doctors will discuss with you whether you are a candidate for brachytherapy.

Proton Therapy

Proton therapy is delivered by a device called a cyclotron. It sends a high-energy beam of protons through the skin toward the tumor.

Unlike photons, proton beams do not penetrate beyond the tumor. That’s the reason why proton therapy reduces the likelihood of side effects caused by damage to normal tissue. Because there could be fewer side effects, proton therapy allows us to use a higher radiation dose on the tumor, maximizing the chance of destroying it.

Proton therapy is extremely helpful for many people. At present, it is most commonly used for mouth cancer that has come back after prior treatment.

Memorial Sloan Kettering is one of a limited number of centers nationwide offering proton therapy.


Sometimes your doctor will recommend chemotherapy as part of your care plan. Chemotherapy can increase the sensitivity of your tumor to radiation treatment. The combination of radiation plus chemotherapy is called chemoradiation.

Cisplatin (Platinol®, Platinol®-AQ) is the most widely used and best studied standard chemotherapy drug used with radiation. Our researchers are studying other drugs that may be used in combination with radiation to further reduce the risk of your cancer returning. These options have different side effects that you may be better able to tolerate. We also think carefully about when to give chemotherapy — before, during, or after radiation. Our team carefully weighs each factor to ensure that we present you with the best strategy possible. 

Clinical Trials

Clinical trials are research studies that test new treatments to see how well they work. People who choose to participate in a trial at MSK receive the most advanced cancer treatment available, sometimes years before it’s offered anywhere else.

For mouth cancer, our researchers are studying immunotherapy, targeted therapies, and other approaches to boost the effectiveness of your radiation therapy. Learn more about clinical trials for mouth cancer.

Side Effects of Radiation Therapy

MSK’s radiation oncologists work hard to minimize the side effects of treatment. They will explain to you in detail what to expect and when side effects are likely to occur.

The most common side effects of radiation to the oral cavity include:

  • changes in your skin that look like a sunburn
  • hoarseness
  • changes in taste
  • dryness of the mouth
  • weakening of teeth
  • pain, sores, or redness in the mouth

Our dental oncology team is available to support you with any problems that may arise with your teeth. They may also fit you with a custom mouth guard to protect your teeth during treatment.

Our rehabilitation team has extensive experience in helping people address the side effects of radiation therapy. A speech and swallowing specialist will meet with you before treatment to discuss any possible changes in your speech, voice, or swallowing. During and after treatment, they will provide you with exercises to prevent side effects. They will look out for any problems you are having with swallowing and make sure you are maintaining the range of motion in your tongue, jaw, and neck.