Oral side effects caused by cancer treatments

Cancer treatments can lead to a number of oral side effects:

  • Soreness and ulcers in the mouth (stomatitis or oral mucositis) − It is common to have a sore mouth. Small cracks and ulcers can form on any soft tissue in your mouth, causing difficulty in eating, talking and swallowing. These can sometimes bleed and become infected. The sores can be very painful and may worsen over time, but will improve when treatment finishes.
  • Mouth changes − You might experience mucositis (ulcers) in the mouth or a dry mouth.
  • Tooth decay − Your teeth may be at increased risk of decay, especially if you have a dry mouth. Oral health care advice before, during and after treatment is important to preserve your teeth and gums.
  • Mouth infections − The most common is thrush, which usually appears as white patches or a white or yellow coating on the lining of the mouth and tongue. This can cause oral discomfort and bad breath.
  • Bleeding gums − Your gums may look red, shiny or swollen and they may bleed. Bleeding may occur if your platelet count falls which can happen with chemotherapy. Platelets are the part of the blood that help it to clot.
  • Taste changes − Cancer treatment may make foods taste different, which can decrease your interest in eating (appetite).
  • Trouble swallowing and opening your mouth fully − This can be caused by head and neck cancer treatment and severe mucositis.

The type of side effects you experience depends on your treatment. Not everyone will have all of these side effects.

Check your mouth, tongue and teeth regularly during cancer treatment. If you have oral side effects, tell your cancer care team. You may be prescribed pain medication, including antiseptic lotions and sprays that can make you more comfortable. Learn more about ways to manage side effects.

      − Mary, head and neck cancer survivor

This information was last reviewed in May 2016
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