Overview of managing cancer pain

Although the general principles of managing acute and chronic pain can be applied to cancer pain, there are several important differences:

• multimodal analgesia is often required because patients may experience multiple types of pain
• pain related to cancer treatments or disease progression may require specific interventions
• analgesics are often required for extended periods, so consideration must be given to the practicality and long-term safety of the analgesic regimen (eg tablet burden, cost, access, long-term opioid-related harms, risk of diversion). The potential for harm (particularly with opioids) must be balanced against the potential for improved function and quality of life
• patients undergoing cancer treatment may be underweight or malnourished, which may necessitate dose modification
• patients may be at increased risk of infection (eg due to neutropenia or immunosuppression), which may influence route of administration.

If the goals of care are palliative, see Principles of managing pain in palliative care. If the patient has a history of a chronic pain syndrome, or an opioid- or other substance-use disorder, seek specialist advice (eg pain medicine physician, palliative care physician). If the patient is a cancer survivor, manage their pain as chronic noncancer pain, with additional attention to the psychosocial impact of cancer survivorship.

When selecting an analgesic for the management of cancer pain, consider the following:

• there is a lack of evidence to support the use of paracetamol for cancer pain but it is often used because of its favourable safety profile in therapeutic doses
• evidence supports the use of nonsteroidal anti-inflammatory drugs (NSAIDs) for nociceptive cancer pain but they should be used with caution because patients may be more susceptible to their adverse effects (eg due to immunosuppression, organ dysfunction or coagulopathy)
• evidence supports the use of opioids for nociceptive cancer pain, but they should only be used when the pain is likely to be opioid responsive. Because cancer pain may be both acute and chronic, concurrent use of modified-release opioids (for background pain) and immediate-release opioids (for breakthrough or incident pain) is often required
• regularly evaluate opioid use—long-term use may necessitate dose titration in people who become opioid tolerant, or opioid rotation in those with dose-limiting adverse effects
• adjuvants  (eg gabapentinoids, tricyclic antidepressants, serotonin and noradrenaline reuptake inhibitors, ketamine) should be considered if pain is not relieved by an opioid or is likely to have a neuropathic component
• if steroid treatment is indicated, discuss its appropriateness with the treating specialist—steroids may interfere with antitumour immunotherapies.