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Oral Complications of Chemotherapy and Head/Neck Radiation (PDQ®)

Patient Version
Last Modified: 04/24/2014

Oral Complications and Their Causes



Cancer treatment can cause mouth and throat problems.

Complications of chemotherapy

Oral complications caused by chemotherapy include the following:

Complications of radiation therapy

Oral complications caused by radiation therapy to the head and neck include the following:

  • Fibrosis (growth of fibrous tissue) in the mucous membrane in the mouth.
  • Tooth decay and gum disease.
  • Breakdown of tissue in the area that receives radiation.
  • Breakdown of bone in the area that receives radiation.
  • Fibrosis of muscle in the area that receives radiation.

Complications caused by either chemotherapy or radiation therapy

The most common oral complications may be caused by either chemotherapy or radiation therapy. These include the following:

  • Inflamed mucous membranes in the mouth.
  • Infections in the mouth or that travel through the bloodstream. These can reach and affect cells all over the body.
  • Taste changes.
  • Dry mouth.
  • Pain.
  • Changes in dental growth and development in children.
  • Malnutrition (not getting enough of the nutrients the body needs to be healthy) caused by being unable to eat.
  • Dehydration (not getting the amount of water the body needs to be healthy) caused by being unable to drink.
  • Tooth decay and gum disease.

Oral complications may be caused by the treatment itself (directly) or by side effects of the treatment (indirectly).

Radiation therapy can directly damage oral tissue, salivary glands, and bone. Areas treated may scar or waste away. Total-body radiation can cause permanent damage to the salivary glands. This can change the way foods taste and cause dry mouth.

Slow healing and infection are indirect complications of cancer treatment. Both chemotherapy and radiation therapy can stop cells from dividing and slow the healing process in the mouth. Chemotherapy may decrease the number of white blood cells and weaken the immune system (the organs and cells that fight infection and disease). This makes it easier to get an infection.

Complications may be acute (short-term) or chronic (long-lasting).

Acute complications are ones that occur during treatment and then go away. Chemotherapy usually causes acute complications that heal after treatment ends.

Chronic complications are ones that continue or appear months to years after treatment ends. Radiation can cause acute complications but may also cause permanent tissue damage that puts you at a lifelong risk of oral complications. The following chronic complications may continue after radiation therapy to the head or neck has ended:

  • Dry mouth.
  • Tooth decay.
  • Infections.
  • Taste changes.
  • Problems in the mouth and jaw caused by loss of tissue and bone.
  • Problems in the mouth and jaw caused by the growth of benign tumors in the skin and muscle.

Oral surgery or other dental work can cause problems in patients who have had radiation therapy to the head or neck. Make sure that your dentist knows your health history and the cancer treatments you received.