Radiation therapy uses high-energy x-rays or particles to destroy cancer cells or slow their rate of growth. Radiation therapy can be used in several situations for oral and oropharyngeal cancers:

• It can be used as the main treatment for small cancers.

• Patients with larger cancers may need both surgery and radiation therapy or a combination of radiation therapy and chemotherapy or a "targeted" agent (see below).

• After surgery, radiation therapy can be used, either alone or with chemotherapy, as an additional (adjuvant) treatment to kill very small deposits of cancer that cannot be seen and removed during surgery.

• Radiation therapy can also be used to relieve symptoms of the cancer, such as pain, bleeding, trouble swallowing, and problems caused by metastases to bones.

External beam radiation therapy

The most common way to give radiation for these cancers is to carefully focus a beam of radiation from a machine outside the body. This is known as external beam radiation therapy. To reduce the risk of side effects, doctors carefully figure out the exact dose needed and aim the beam as accurately as they can to hit the carefully outlined target. External beam radiation therapy usually means having treatments 5 days a week for 6 to 7 weeks.

Newer radiation approaches, such as giving radiation twice a day (accelerated fractionation or hyperfractionation) or using more focused techniques like 3-dimensional conformal radiation therapy (3D-CRT) or intensity modulated radiation therapy (IMRT), are now being used as well.

Accelerated and hyperfractionated radiation therapy: Many clinical trials have found that tumors can be better controlled if patients get radiation twice a day (as opposed to once a day) during some or all of the treatment days, although it may cause more side effects.

Three-dimensional conformal radiation therapy (3D-CRT): 3D-CRT uses special computer programs to precisely map the location of the cancer. Radiation beams are then shaped and aimed at the tumor from several directions, which makes it less likely to damage normal tissues. In theory, by aiming the radiation more accurately, doctors can reduce radiation damage to important normal tissues in the area (such as nerves, blood vessels, and other organs) and may be able to cure more cancers by increasing the radiation dose to the tumor itself. Long-term study results are still needed to confirm this.

Intensity modulated radiation therapy (IMRT): IMRT is an advanced form of 3D therapy. It uses a computer-driven machine that actually moves around the patient as it delivers radiation. In addition to shaping the beams and aiming them at the tumor from several angles, the intensity (strength) of the beams can be adjusted to minimize the dose reaching the most sensitive normal tissues. This allows doctors to deliver an even higher dose to the cancer areas.

Brachytherapy

Another way radiation treatment is given is by placing radioactive materials directly into or near the cancer. This method is called internal radiation, interstitial radiation, or brachytherapy. Different types of brachytherapy may be used.

High-dose rate (HDR) brachytherapy: For this technique, hollow catheters (thin tubes) are placed into or around the tumor in the operating room. This may require general anesthesia (where the patient is in a deep sleep). They are left in place for several days while the patient stays in the hospital. The catheters themselves are not radioactive. The actual radiation treatment takes place each day in a special room in the hospital. The catheters are hooked up to a machine that inserts radioactive materials into them for a short time and then removes them. Patients are not radioactive in between or after treatments. The catheters are removed before the patient goes home.

Low-dose rate (LDR) brachytherapy: This type of brachytherapy may be done in 2 ways.

In the temporary approach, the doctor implants thin, hollow, plastic tubes into and around the tumor. These tubes are loaded with tiny radioactive pellets (called seeds) that remain in place for a few days to kill the cancer. The patient stays in the hospital during treatment. Although the radiation travels a very short distance, the length of time that visitors, nurses, and other caregivers can spend with the patient will be limited as a precaution. The seeds and the tubes are removed before the patient goes home. The patient is not radioactive after treatment.

Permanent brachytherapy is rarely used to treat these cancers any more. For this technique small radioactive pellets (about the size and shape of a grain of rice) are placed directly into the tumor. The pellets give off low levels of radioactivity for several weeks and eventually lose their strength. The pellets themselves are left in place permanently and rarely cause any problems.

Sometimes, both internal and external beam radiation therapy are used together.

Last Medical Review: 09/24/2009
Last Revised: 09/24/2009