Pain is a common symptom in cancer of the head and neck. Pain may be caused by direct tissue damage due to the disease, or as a result of treatment, both as an immediate side effect of chemotherapy or radiotherapy, or as late sequelae, such as from fibrosis and neovascularization post- radiotherapy. These must be distinguished from other common causes of head and neck pain, such as tension headache, migraine, toothache and trigeminal neuralgia. Accurate assessment of the cause and pathophysiology of the pain is the first step to good pain management.

Pain due to direct tumour damage includes ulcerative lesions of the mouth and palate, tumour destroying bony structures and tumour affecting the cervical spine causing radicular pain of the head and neck. Often the pain is exacerbated by muscle spasm, which is usually reactive and often protective. NSAIDs and COX-2 inhibitors are often useful in ulcer or bone pain, with addition of opioids if pain is more severe. Muscle relaxants, such as baclofen, may help with muscle spasm, though they have to be used judiciously if there is facet joint or spinal instability. Neuropathic pain needs to be treated with adjuvant drugs such as amitriptyline, sodium valproate, gabapentin or pregabalin, in addition to analgesics.

The commonest cause of pain due to cancer treatment is mucositis. Transcription factors, such as NF- k B, activated by chemotherapy, radiation therapy or reactive oxygen species play a major role in triggering a biological cascade that leads to mucosal injury. Mucositis may range in severity from generalized mucosal erythema to widespread ulceration, which may be life threatening, depending on the agent and dosing regimen. Treatment is directed towards control of pain and risk of infection.

A common infection causing pain in immunosuppressed patients is oral candidiasis. This may extend into the oropharynx and oesophagus giving rise to odynophagia and compromising oral intake of food and fluids. Management is by removal of Candida plaques with bicarbonate solution and treatment with oral nystatin suspension 500,000 Units four times daily, or in severe cases, with systemic antifungal agents, such as fluconazole. Other infections causing pain include Herpes simplex and zoster reactivation. The latter may also cause post-herpetic neuralgia.

Other oral complications of cancer treatment of the head and neck include osteonecrosis of the mandible and radiation tooth caries. It is important before the start of cancer treatment to have dental clearance of tooth and gum disease. Osteoradionecrosis of the mandible is a known complication of radiation treatment, and may be precipitated by a tooth extraction or other trauma to the irradiated bone. It is often very troublesome to treat, as dead bone sequestrae may have to be removed and sometimes the mandible replaced. Hyperbaric oxygen has also been tried. A more recently reported cause of osteonecrosis is that associated with the use of intravenous bisphosphonates.


Dr Cynthia Goh
Head of Palliative Medicine
National Cancer Centre, Singapore