Radiation therapy for pharyngeal cancer

Radiation therapy uses high-energy rays or particles to destroy cancer cells.

Most people with pharyngeal cancer have radiation therapy. Your healthcare team will use what they know about the cancer and about your health to plan the type and amount of radiation, and when and how it is given.

Radiation therapy and chemotherapy are most often given during the same time period to treat pharyngeal cancer. This is called chemoradiation. Some chemotherapy drugs can help make radiation work better by making cancer cells more sensitive to radiation. Combining chemotherapy and radiation therapy can be more effective than either treatment on its own.

You may have radiation therapy or chemoradiation:

• as the main treatment for small tumours
• to destroy any cancer cells left behind after surgery, reducing the risk that the cancer will come back (called adjuvant therapy)
• to shrink a tumour before surgery (called neoadjuvant therapy)
• to relieve pain or control the symptoms of advanced pharyngeal cancer (called palliative therapy)
• to treat cancer that comes back after other treatments

Talk to your healthcare team to find out what you need to do before radiation therapy begins. They may discuss any or all of the following, depending on your personal needs.

Smoking tobacco during treatment may make radiation therapy for pharyngeal cancer less effective. Smoking may also make side effects from radiation therapy or chemoradiation worse.

If you smoke, your healthcare team will talk to you about how they can help you quit before you start radiation therapy.

It’s important to have a complete dental exam before radiation therapy begins to prevent dental problems that can be caused or made worse by radiation therapy. This includes problems with your teeth, gums and the bones of your jaw, and a dry mouth.

Your dentist will determine if you need to have any dental work done before treatment, such as having unhealthy teeth removed, and treating any gum disease or infections. They will also develop a dental care plan for you to follow after radiation therapy. Following the plan will help you maintain a healthy mouth.

Many people have a custom immobilization mask made before external radiation therapy is given to the head and neck. The mask makes sure that you don’t move during treatment and that radiation is directed at exactly the same place each time. You will need to wear it during treatment planning and all radiation treatments.

Radiation therapy to the head and neck can make swallowing difficult and painful. A feeding tube can help make sure you get the nutrition you need.

Before radiation therapy for pharyngeal cancer, you may have a feeding tube inserted using either a percutaneous endoscopic gastrostomy (PEG) or a percutaneous endoscopic jejunostomy (PEJ) procedure. If you’re given the PEG feeding tube, it’s passed through the skin into the stomach. If you’re given the PEJ feeding tube, it’s inserted into the small intestine. Food and liquids are given to you through these tubes so that you can get the nutrition you need during treatment.

Find out more about tube feeding.

Radiation therapy for pharyngeal cancer can cause nerve damage or fluid buildup in the middle ear. This can affect your hearing, so it’s important to protect your ears as much as possible.

The healthcare team may place tubes in one or both ears before radiation therapy starts. These tubes drain fluid and air from the middle ear. They usually fall out on their own, but the doctor might have to remove them after treatment in some cases.

Both the thyroid and pituitary glands may be in the area treated with radiation therapy for pharyngeal cancer. Radiation can affect these structures, so the healthcare team takes special care to protect them during treatment. They will also do blood tests before, during and after radiation therapy to check how well the thyroid and pituitary glands are working.

During external radiation therapy, a machine directs radiation through the skin to the tumour and some of the tissue around it. External radiation therapy is also called external beam radiation therapy.

Doctors may use the following external radiation techniques to accurately target the area to be treated and spare as much surrounding normal tissue as possible.

3D conformal radiation therapy (3D CRT) delivers radiation to the tumour from different directions. The radiation beams are all the same strength.

Intensity-modulated radiation therapy (IMRT) uses computer-generated images to deliver radiation directly to the tumour or lymph nodes from many different angles. A higher dose can be given to the tumour while the normal tissues near the tumour get less radiation. It may be used for pharyngeal cancer when there is little risk that cancer cells have spread into the surrounding tissue.

Stereotactic radiosurgery delivers one large dose of radiation to a tumour as a single treatment, called a single fraction. It doesn’t involve surgery. It may be given as a boost after external radiation therapy or chemoradiation for recurrent pharyngeal tumours.

Brachytherapy is internal radiation therapy. It uses a radioactive material called a radioactive isotope that gets placed right into the tumour or very close to it. Radioactive materials can also be placed in the area where the tumour was removed. The radiation kills the cancer cells over time.

Brachytherapy may be used to treat a small, early-stage nasopharyngeal tumour or for nasopharyngeal cancer that comes back after external radiation therapy. It may also be given as a boost along with external radiation.

During radiation therapy, your healthcare team protects healthy cells in the treatment area as much as possible. Side effects of radiation therapy will depend mainly on the size of the area being treated, the specific area or organs being treated, the total dose of radiation, the treatment schedule, and whether or not chemotherapy is being given at the same time (chemoradiation). Tell your healthcare team if you have side effects that you think are from radiation therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

These are common side effects of radiation therapy for pharyngeal cancer:

• skin problems
• fatigue
• sore mouth and throat
• dry mouth
• taste changes
• hoarseness
• thickened saliva
• hearing problems
• eye and vision problems
• thyroid problems
• tooth decay
• difficulty opening the jaw (called trismus)
• infection and the breakdown of surrounding bones (osteoradionecrosis)

Find out more about radiation therapy and the side effects of radiation therapy. To make the decisions that are right for you, ask your healthcare team questions about radiation therapy.