Side effects

Most people have some side effects from radiotherapy to the salivary gland area. They come on gradually during the course of treatment and are usually at their worst at the end of treatment. 

The side effects slowly get better over the 2 to 3 weeks following treatment. But it can take quite a few months to completely get over a long course of treatment.

Everyone is different and the side effects vary from person to person. You may not have all of the effects mentioned.

Side effects can include:

Your skin might go red or darker in the treatment area. You might also get slight redness or darkening on the other side of your body. This is where the radiotherapy beams leave the body. 

The red or darker areas can feel sore. Your radiographers will give you creams to soothe your skin. The soreness usually goes away within 2 to 4 weeks of ending the treatment. But your skin might always be slightly darker in that area.

Tell the radiotherapy staff if you notice any skin changes.

You might feel tired during your treatment. It tends to get worse as the treatment goes on. You might also feel weak and lack energy. Rest when you need to.

Tiredness can carry on for some weeks after the treatment has ended but it usually improves gradually.

Various things can help you to reduce tiredness and cope with it, such as exercise. Some research has shown that taking gentle exercise can give you more energy. It's important to balance exercise with resting.

Radiotherapy to the salivary glands can reduce the amount and quality of saliva produced. 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.

Having a dry mouth can be uncomfortable. Various things can help.

  • Try to drink at least 3 pints (one and a half litres) of fluid a day
  • Choose meals that are moist.
  • Use gravies and sauces to make swallowing easier.
  • Take regular sips of water with your meal to help you chew and swallow your food.
  • Suck small amounts of ice chips to refresh your mouth.
  • Chew sugar free chewing gum.
  • Try eating fresh pineapple.
  • Get your doctor or nurse to give you medicines to stimulate your salivary glands.
  • Ask your doctor or pharmacist about artificial saliva products, such as tablets, mouthwashes, gum, pastilles, and toothpaste.
  • It is very important to have regular check ups with 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.

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

Your mouth and throat may get increasingly sore with mouth ulcers as you go through your treatment. 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 on 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.

Radiotherapy to the head or neck often affects taste. You may lose your sense of taste, have strange tastes or a dull taste. Some people describe a metallic taste in their mouth after radiotherapy.

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 changed.

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.

You might need to have some teeth taken out before you start treatment. Your doctor may refer you to a restorative dentistry consultant before your radiotherapy. A restorative dentist is a specialist in 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.

Your dentist might need to change the way they treat you. They may also need to talk to your radiotherapy doctor before giving you any treatment.

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

You might find that having a soft diet is easier to swallow until a few weeks after your treatment is over. Foods such as soups and stews are easier to swallow than more solid foods like meat or toast.

Your radiotherapy department can give you an information sheet to help advise you.

Tell your doctor or radiographers if you have problems swallowing. They can advise you on ways to reduce this.

Ask to see a dietitian if you have problems with eating and drinking.

Tips for eating and drinking
  • Drink about 8 glasses of water a day while having treatment.
  • Make sure that you eat slowly and avoid eating late in the day.
  • Drink plenty during and after meals to soften your food.
  • Eat small amounts often rather than big meals.
  • Try different foods to find out which are easiest to swallow.
  • You can have high calorie drinks to boost your calorie intake if you need them.

Radiotherapy causes some hair loss to the area of treatment. It can also cause hair loss on the opposite side of the head. This is where the radiotherapy beam leaves the body (the exit site). 

Most of the hair loss can recover unless the full radiation dose needs to be given to the underlying skin.

You might feel sick at times. You can have anti sickness medicines. Let your treatment team know if you still feel sick, as they can give you another type.   

Long term side effects

Most side effects gradually go away in the weeks or months after treatment. But some side effects can continue or might start some months or years later.

Last reviewed: 
05 Nov 2019
  • Management of Salivary Gland Tumours: United Kingdom National Multidisciplinary Guidelines

    S Sood and others

    The Journal of Laryngology & Otology, 2016. Vol 130, Supplement S2

  • Lymphedema Outcomes in Patients with Head and Neck Cancer
    B Smith and others
    Otolaryngology Head and Neck Surgery, 2015. Vol 152, Issue 2

  • Cancer and its Management (7th edition)

    J Tobias and D Hochhauser

    Wiley Blackwell, 2015

  • External Beam Therapy
    Peter Hoskin
    Oxford University Press, 2012

Related links