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Radiotherapy and Oral Health

What is radiotherapy?

It is a modality used to treat cancer. It is used either as the primary treatment or as an adjuvant treatment following cancer surgery. The radiation is delivered only to the area of cancer cells prescribed by an oncologist in small amounts (fractions), daily for 10 to 15 minutes for a period of 20 to 30 days. Daily dosage is usually 2 Gy (Grays) and it is delivered to a maximum of 64-70 Gy. The dosage given usually spares normal tissues.

When radiotherapy is used to treat cancer in the head, neck and mouth area, it may affect oral health.

Effects of radiotherapy on oral health.

The effects of radiotherapy on a patient can be divided into:-

  1. Early effects
  2. Late effects

Early effects

  1. Mucositis

    Mucocitis is the inflammation of the oral mucosa. This takes place 10 to 12 days after the start of radiation. There are symptoms of soreness and pain due to ulcers in the mouth. Mucositis will normally heal by itself after completion of radiotherapy. In the meantime, oral hygiene is maintained by using a soft bristle toothbrush and if unable to use toothbrush, then a saline-soaked gauze is used to clean the teeth regularly and 0.01% chlorhexidine mouthwash gargling is undertaken. For the pain, topical anaesthetic is applied over the mucosal surface and analgesics or non-steriodal-anti-inflammatory (NSAID) is prescribed. Benzydamine mouthwash is also useful as it numbs the mouth and relieves the oral soreness. Smoking must be avoided and dentures not used during this period.

  2. Dysphagia (difficulty in swallowing)

    This is due to a reduce flow of saliva (xerostomia), mucocitis or the surgery. Immediately after the surgery, the patient is placed on a feeding tube via the nose and nourishing fluids is given. Alternatively, a feeding gastrotomy tube (tube into the stomach) is placed and family members are thought on patient nourishment.

  3. Xerostomia (Dry mouth)

    Salivary and mucus glands are vulnerable to radiation. Dry mouth begins within a few days from the start of radiation. In most patients, this becomes worse over weeks and the effects may prolong after radiotherapy has been completed. Due to mouth dryness, problems like difficulty in chewing, dysphagia, tooth decay and etc is seen. The patient is advised to consume small amounts of water regularly and if necessary salivary substitute is prescribed.

  4. Loss of taste sensation

    Taste loss can be distressing and contributes to poor nutrition. Taste function usually recovers slowly in a few months. Prolonged taste loss could be overcomed by the administration of medications.

  5. Skin reaction

    Commonly appears about 3 weeks later since radiotherapy is commenced. It is managed conservatively and could take about a month to heal post-radiotherapy.

  6. Epilation (hair loss)

    This occurs close to the area of radiotherapy. It maybe permanent in nature.

  7. Infection

    When mucocitis or xerostomia occurs, there may be secondary superinfection with candidial fungus. Advocating proper oral hygiene during radiation treatment is important and 0.01% chlorhexidine mouthwash is used for 1 minute and gargled 3 to 4 times per day. An anti-fungal gel if necessary is applied over the affected region. Systemic anti-fungal may be required if blood culture is positive.

Late effects

  1. Soft tissue necrosis (skin ulcer)This occurs over a period of time causing “radionectotic ulcer” especially over the site of treatment. They are flat ulcers with a leathery feeling, tender and deep pain. They must not be misdiagnosed a having a recurrent cancer.
  2. Trismus (limitation in mouth opening)This occurs due to fibrosis (hardening) of oral muscles causing limitation in mouth opening. Patients are informed on the type of physiotherapy undertaken as this could lead to a permanent feature.
  3. Osteoradionecrosis (bone death)

    This means death to the irradiated part of the bone. Radiotherapy causes temporary or permanent loss of blood supply to the bone especially to the affected areas. It is a severe bone disease and affects mainly the lower jaw. The disease destroys part of the bone and bone cell therefore unable to produce new bone over the irradiated region. This maybe spontaneous or due to denture-induced trauma leading to soft tissue loss and bone necrosis. It may also occur following a tooth extraction. The necrotic bone may become secondarily infected. This destruction of bone will have to be treated through surgery. Therefore, dental extraction and gum problems must be treated prior to radiotherapy. Osteoradionecrosis is a serious complication for patients requiring tooth extraction after radiotherapy.

  4. Radiation caries (tooth decay)

    Teeth that are in the line of irradiation will become more sensitive and be more susceptible to decay. More over, the ulcers in the mouth make regular tooth brushing difficult. The reduced saliva flow also contribute to tooth decay. This normally occurs along the gum margin, affecting the neck of the teeth. Over time, if untreated, the crown of the tooth may break off, leaving a root stump.

    To lessen the effect of tooth decay, the patient need to practise gentle oral hygiene with soft bristled toothbrush and fluoridated toothpaste. Mouth gargling with a chlorhexidine mouthwash should also be practised together with tooth brushing. Regular visits to the dentist for application of fluoridated varnish/gel is also advised.

What to do before radiotherapy?

Prior to radiotherapy it is mandatory for the patient to be referred to a dental clinic. Patients will be educated on the management of oral health problems and complications of surgery/ radiotherapy . Proper oral hygiene care and regular checkup is mandatory. The dentist will undertake :-

  • Assessment of prognosis of existing restorations (fillings).
  • Assessment of gum status.
  • Extraction of teeth with poor prognosis (at least 4 weeks prior to radiotherapy).
  • Replacing ill fitting dentures.
  • Oral hygiene instructions.

What to do after radiotherapy?

  • Oral hygiene instructions- use of soft bristle toothbrush or gauze soaked in salt water to clean the teeth especially after radiotherapy. A fluoride toothpaste is used and commonly prescribed is a fluoridated tooth varnish.
  • Dietary advice with less sugar intake.
  • Smoking and alcohol consumption should be avoided.
  • Frequent consumption of small amounts of water to keep oral passage moist.
  • Saliva substitute and chewing gum (for patients without dentures) if saliva flow is reduced.
  • Regular dental follow-up and application of fluoride.

What to do if your mouth is dry?

Dry mouth is when the salivary glands in the mouth is unable to produce enough saliva. Ways to manage dry mouth:-

  • Sip water throughout the day. This helps moisten the mouth which helps in swallowing. Many patients carry along with them a bottle of water.
  • Have citrus based drinks (e.g. lemonade, orange juice) as these help make more saliva.
  • Chewing sugar free gum help make saliva and moisten the mouth.
  • Eat food that are easy to swallow (e.g. porridge, pureed cooked food or soup).
  • Avoid smoking or alcohol consumption as these make the mouth drier.
  • Avoid foods that are spicy, salty, sour, hard or crunchy.
  • Keep lip moist with lip balm.
  • Rinse mouth every 1- 2 hours (mix 1/4 teaspoon of baking soda and 1/8 teaspoon salt in a glass of water).

References

  1. Meurman JK, Scully C (2011). Other risk factors. Dental Update, 38(1), 66-68
  2. Waal IVD, Scully C (2011). Potentially malignant disorder of oral and oropharyngeal mucosa. Dental Update, 38(2), 138-140
  3. Nutting CM, Scully C (2011). Radiotherapy and chemotherapy. Dental Update, 38(10), 717-719
  4. Langdon JD, Henk JM (1995). Tumours of the mouth, jaws and salivary glands. Edward Arnold

 

Last Reviewed : 20 March 2015
Writer : Dr. Sathiadeva a/l Sathiavan
Accreditor : Dr. Yuen Kar Mun
Reviewer : Dr. Mukhriz bin Hamdan

 

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