Your doctor may use radiation therapy for any of these reasons:

• To kill cancer cells that might be left in the area after surgery and lower the chance that the cancer will come back

• For tumors that can't be removed with surgery

• As a primary treatment for some early stage tumors, which may help preserve your voice quality

• If you can't have surgery for other reasons

• For a tumor that comes back after surgery

• To help ease symptoms caused by advanced cancers 

Radiation to the head and neck area can cause problems with tissue healing after dental work. For this reason, your doctor may suggest you have a full dental exam before starting radiation. If you have dental problems, the doctor will want you to have an exam as soon as possible before radiation starts. Some or all of your teeth may need to be removed because radiation can worsen any existing dental problems.

There are 2 main types of radiation therapy: external beam radiation treatment (EBRT) or internal radiation, also called brachytherapy. 

Radiation therapy affects normal cells as well as cancer cells. The side effects of radiation depend on the amount and the type of radiation you get, as well as the area of the body being treated. It also depends on whether you are getting chemotherapy along with the radiation.

Radiation to the neck and throat area can cause painful sores in your mouth and throat. This can make it painful to chew and swallow. Because of this, you may not eat enough food. These sores typically go away a few weeks after radiation ends. But to prevent weight loss and malnutrition, your doctor may choose to put a feeding tube directly into your stomach. This is to help you take in enough food. This tube is called a percutaneous endoscopic gastrostomy (PEG) tube. It is inserted through a small cut or incision in your belly. The PEG tube is removed when it's no longer needed.

Other side effects from radiation therapy may include:

• Skin reddening or irritation in the treated area

• Dry mouth

• Sore throat

• Hoarseness

• Trouble swallowing

• Decreased sense of taste

• Loss of appetite

• Trouble breathing because of swelling

• Tiredness

• Swelling or scarring

Side effects of radiation can be more severe when it's given together with chemotherapy. In rare cases, radiation may lead to a breakdown of cartilage that can further damage your larynx. Or it may damage your windpipe or trachea.

Radiation to the neck area might damage the thyroid gland. This may make you feel tired, gain weight, feel cold, and have dry skin or hair. If this happens, you may need to take thyroid hormone pills. 

Radiation near the salivary glands may cause dry mouth. This may continue even after treatment is done, because of lasting damage to the salivary glands. People with dry mouth after radiation must pay close attention to their oral health. That’s because dry mouth can cause problems with tooth decay.

Most side effects go away after treatment. Talk to your doctor about what radiation side effects you might have and how these side effects might be prevented or managed.