Synopsis
Identify the biological and psychosocial drivers of cancer pain, exclude time-critical complications, combine tumour-directed, pharmacological and non-drug treatment and initiate, titrate, switch and stop opioids with explicit safety, bowel and monitoring plans.
- Assess pain by site, onset, quality, radiation, severity at rest and movement, breakthrough pattern, sleep and function; examination and investigation must explain a new pattern.
- First exclude emergencies: cord compression, fracture, intracranial pressure, obstruction, infection, thrombosis and serious treatment toxicity need anatomical or cause-specific rescue.
- Classify somatic, visceral, neuropathic and incident pain because opioids, anti-inflammatory treatment, adjuvants, radiotherapy, surgery and procedures address different mechanisms.
- For moderate-to-severe pain from advanced progressive disease, oral morphine is the NICE first-line strong opioid when oral treatment and renal function permit.
- In an opioid-naive adult, a typical starting total oral morphine dose is 20 to 30 mg per day with 5 mg immediate-release rescue; start lower in frailty and seek specialist advice in renal impairment.
- Prescribe immediate-release rescue alongside regular opioid and review total use; repeated rescue need usually prompts reassessment and proportionate regular-dose adjustment, not an unlimited repeat supply.
- Start a regular laxative when a strong opioid starts, and offer an antiemetic if nausea occurs; tolerance develops to some nausea and sedation but not reliably to constipation.
- Use modified-release oral morphine for stable background pain or regular immediate-release during titration according to patient preference and service capability; both require breakthrough access.
- Transdermal fentanyl is useful for stable opioid-responsive pain when swallowing or adherence makes oral medicine unsuitable, but it is not a rapid-titration patch for an opioid-naive crisis.
- Neuropathic pain may need duloxetine, amitriptyline, gabapentin or pregabalin selected by comorbidity and interaction; specialist radiotherapy, nerve block or neuraxial treatment can reduce opioid burden.
- Before an opioid switch, calculate the current 24-hour oral-morphine equivalent, check renal and liver function and reduce the calculated equianalgesic dose for incomplete cross-tolerance with specialist verification.
- Pain on movement from unstable bone will not be made safe by sedation; protect loading and obtain surgical or radiotherapy review.
- New difficult rousing or slow breathing requires withheld opioid, airway and ventilation support and titrated naloxone, followed by observation longer than the antagonist effect.
- Review benefit against alertness, bowel function, falls, driving, adherence and patient goals; taper a regular opioid gradually when pain resolves or harm exceeds benefit.
Key red flags
Back pain with weakness, gait change, sensory loss or bladder or bowel dysfunction requires immediate metastatic-spinal-cord-compression assessment and whole-spine MRI.
Sudden movement-related long-bone pain, inability to weight bear or deformity indicates impending or completed pathological fracture and needs urgent orthopaedic stabilisation review.
Severe new headache, vomiting, focal deficit, seizure or falling consciousness can reflect intracranial pressure, haemorrhage or infection and requires emergency imaging.
Rapidly increasing abdominal pain with guarding, vomiting, obstipation, fever or hypotension suggests obstruction, perforation, ischaemia or sepsis rather than uncomplicated cancer pain.
Respiratory rate below 8 per minute, difficult rousing, cyanosis or pinpoint pupils after opioid exposure requires immediate ventilation support and proportionate naloxone.
New pain during immunotherapy, bisphosphonate, anticoagulant or steroid treatment may signal immune toxicity, jaw osteonecrosis, bleeding, infection or fracture and should not be masked by extra opioid.
Escalating dose without analgesia, prominent allodynia or pain spreading beyond the original site raises tolerance, opioid-induced hyperalgesia, progression or a misclassified mechanism.
Investigation priorities
Define each pain’s mechanism, severity, breakthrough pattern, functional effect, current exposure, understanding and psychosocial context.
Management branches
Pain appears, changes character or becomes difficult to control.
- Assess each site, mechanism, rest and movement severity, function, neurological and skeletal signs, bowel pattern, current medicines and psychosocial distress.
- Activate emergency imaging and specialist pathways for cord, brain, fracture, obstruction, infection or treatment toxicity and protect unsafe movement while anatomy is clarified.
- Treat the cause through cancer therapy, surgery, radiation, drainage or antimicrobial treatment while starting mechanism-appropriate analgesia and a documented review time.