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Side effects

Read about the side effects of radiotherapy for salivary gland cancer and how to manage them.

When side effects happen

The side effects of radiotherapy usually come on gradually during your course of treatment.

Most people have some side effects from radiotherapy to the salivary gland area. They are usually at their worst at the end of your course. 

Over the 2 to 3 weeks following your treatment, they slowly get better. It may take up to 6 weeks before the soreness has entirely gone.

Getting over a long course of treatment completely can take quite a few months.

General side effects

Generally, radiotherapy causes tiredness and sore, red skin in the treatment area. This is a bit like sunburn. You may also feel sick for a while after the treatment.

Remember not to put any lotions, powders or creams on the skin in the radiotherapy treatment area, without checking first with your radiotherapy department. If the skin is sore, some creams can make things worse, not better. If you need it, ask the staff in the radiotherapy department for something to soothe your skin.

Dry mouth

The salivary glands make saliva, which keeps your mouth and throat moist and your teeth healthy. It also helps make swallowing and digestion of food easier, and helps your sense of taste.

Radiotherapy to the salivary glands stops them making saliva. You see a restorative dentistry consultant before you start treatment.

Usually only the glands on the treated side of your face are affected. This means that glands on the other side should still make saliva.

Rarely, some people have a permanently dry mouth after the treatment. This can make eating and talking uncomfortable.

If you have trouble with a dry mouth, the team caring for you can prescribe artificial lubricating agents and stimulants for your salivary glands.

These help to keep your mouth moist and make you more comfortable. They also reduce the chance of infections or tooth decay. You need to have regular check ups from your dentist.

Most people start making saliva again within 4 to 8 weeks of finishing treatment. The saliva is likely to be quite thick and may taste unpleasant at first.

Sore mouth and throat

Your mouth and throat may get increasingly sore with mouth ulcers as you go through your treatment. If they are very sore, you may need strong painkillers such as morphine. 

Your doctor may also prescribe a mouth gel such as Gelclair. This gel forms a protective barrier over the inside of the mouth, a bit like a dressing.

This can make your mouth less painful. You will then find it easier to eat and drink.

Taste changes

Radiotherapy to the head or neck often affects taste. You may lose your sense of taste, or have strange tastes, or dulled taste.

People often describe a metallic taste in their mouth after radiotherapy and some types of chemotherapy. 

Loss of taste can reduce your appetite. This doesn’t help when you are finding it difficult to eat anyway.

Although you can recover your sense of taste, some people may find it is permanently dulled.

Hearing loss

Standard radiotherapy for parotid gland cancer may cause damage to the inner ear and hearing loss.

Problems with your teeth

Radiotherapy to your mouth can make you more likely to get tooth decay. You need to go for check ups at the dentist more often. Fluoride treatment may help to protect your teeth. You can have this as a mouthwash to use twice a day.

Sometimes you might have to have some teeth taken out before you start treatment. Your specialist may refer you to a restorative dentistry consultant before your radiotherapy. A restorative dentist is a specialist in removing or replacing lost tissues and teeth. 

Remember to tell your dentist that you have had radiotherapy to your salivary glands before you have any dental work.

Any dental work that needs to be done should be carried out by a restorative dentistry consultant. If you need to have teeth removed following radiotherapy treatment, this should be done under the care of a maxillofacial surgeon. 

Oral and maxillofacial surgeons are highly qualified, and are trained both as doctors and dentists. They specialise in the surgical treatment of a wide variety of conditions affecting the mouth, jaw, face and neck, including reconstructive surgery and facial plastic surgery.

Swelling (lymphoedema)

After radiotherapy to treat a head and neck cancer, you are at risk of getting swelling called lymphoedema in your neck or face.

Lymphoedema in the head or neck area might also cause swelling of your tongue and other parts of your mouth.

Tell your doctor if you:

  • have any swelling in the head or neck area or a feeling of fullness or pressure
  • find it difficult to swallow
  • have changes in your voice
Last reviewed: 
01 Jul 2014
  • External Beam Therapy
    Peter Hoskin
    Oxford University Press, 2012

  • Lymphedema Outcomes in Patients with Head and Neck Cancer
    B Smith and others
    Otolaryngology Head and Neck Surgery. 2015 February; 152(2): 284–291.

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