At more than 6 months postsurgery, impairment due to moderate to severe pain may be seen in approximately one-third of patients. Analgesics and physiotherapy are commonly used in pain management in these patients. Long-term HNC survivors (>3 years) continue to suffer from more pain and functional problems. Surgery-related pain involves inflammatory and neuropathic pain mechanisms.
Postradiation osteonecrosis and bisphosphonate-associated osteonecrosis are recognized oral complications that may cause pain; clinical presentation may include pain, swelling, and bone exposure. Oral GVHD represents a local manifestation of a systemic disease post-HCT that may result in mucosal and arthritic pain. Viral reactivation of herpes viruses may cause pain. Postherpetic neuralgia may result in chronic pain causing painful dysesthesias in the affected area that may persist for years.
Treatment of Pain in Cancer Patients
Pain management should be directed at the diagnoses of etiologic factors, pain mechanisms involved, and pain severity. (Refer to the PDQ summary on Pain for more information.) Pain mechanisms in cancer include the following:
- Malignant disease.
- Complications of treatment.
- Tumor invasion, pressure on structures, or ulceration of mucosal surface.
- Nociceptive pain.
- Neuropathic pain.
Management of pain due to oral mucositis
Oral mucositis pain is associated with release of proinflammatory cytokines and neurotransmitters that activate nociceptors at the site of injury and may be increased by secondary mucosal infection. Pain experience is influenced by anxiety, depression, sociocultural variation, and quality and quantity of sleep.
Topical approaches for mucosal pain relief
Topical anesthetics have a limited duration of effect in mucositis pain (15-30 minutes), may sting with application on damaged mucosa, and affect taste and the gag reflex. Some patients will apply local anesthetics directly to specific sites of ulceration, but no controlled studies have been reported.
Topical anesthetics are often mixed with coating and antimicrobial agents such as milk of magnesia, diphenhydramine, or nystatin but have not been subjected to controlled studies. However, these mixtures result in dilution of each component, which may limit the therapeutic effect. In addition, various agents in the mix may interact, reducing the effect of the components.