Cancer pain in adults – ESMO guidelines

Priscilla Lynch reports on the most recent ESMO Clinical Practice Guidelines on Cancer Pain

Pain is common in cancer patients, particularly in the advanced stage of disease when prevalence is estimated to be more than 70 per cent. Due to ever increasing cancer survival rates there are consequently increased numbers of patients experiencing persistent pain due to treatment. Despite guidelines and the availability of opioids, under treatment is common, according to the European Society for Medical Oncology (ESMO), which has recently issued updated guidelines in the area. The 2018 ESMO Clinical Practice Guidelines on Cancer Pain are based on the most recent data available. New recommendations are given for the key pain assessment question, step 2 of the analgesic ladder and for ketamine and cannabinoid use. Updated guidelines for breakthrough cancer pain, bone and neuropathic pain are included.

The key recommendations are as follows:
Assessment
The intensity of pain and the treatment outcomes should be assessed regularly and consistently using the visual analogue scale (VAS) or numerical rating scale (NRS) and the worst pain question.
Observation of pain-related behaviours and discomfort is indicated in patients with cognitive impairment to assess the presence of pain.
The assessment of all components of suffering such as psychosocial distress should be considered and evaluated.
Principles of pain management
Patients should be informed about pain and pain management and should be encouraged to take an active role in their pain management .
The onset of pain should be prevented by means of around-the-clock (ATC) administration, taking into account the half-life, bioavailability and duration of action of different drugs.
Analgesics for chronic pain should be prescribed on a regular basis and not on an ‘as required’ schedule.
The oral route of administration of analgesic drugs should be advocated as the first choice.
Treatment of mild pain
Analgesic treatment should start with drugs indicated by the World Health Organisation (WHO) analgesic ladder appropriate for the severity of pain.
There is no significant evidence to support or refute the use of paracetamol alone or in combination with opioids for mild to moderate pain.
There is no significant evidence to support or refute the use of NSAIDs alone or in combination with opioids for mild to moderate pain.
Treatment of mild to moderate pain
For mild to moderate pain, weak opioids such as tramadol, dihydrocodeine and codeine can be given in combination with non-opioid analgesics.
As an alternative to weak opioids, low doses of strong opioids could be an option, but is not included in WHO guidance.
There is no evidence of increase in adverse effects from the use of low-dose strong opioids instead of the standard step 2 approach with weak opioids.
Treatment of moderate to severe pain – strong opioids
The opioid of first choice for moderate to severe cancer pain is oral morphine.
The average relative potency ratio of oral to IV morphine is between 1:2 and 1:3.
The average relative potency ratio of oral to subcutaneous (sc) morphine is between 1:2 and 1:3.
Fentanyl and buprenorphine (via the transdermal (td) or IV route) are the safest opioids in patients with chronic kidney disease stages 4 or 5 (estimated GFR<30mL/min).
A different opioid should be considered in the absence of adequate analgesia (despite opioid dose escalation) or in the presence of unacceptable opioid side-effects.
The sc route is simple and effective for the administration of morphine, diamorphine and hydromorphone and it should be the first-choice alternative route for patients unable to receive opioids by oral or td route.
IV infusion should be considered when sc administration is contraindicated (peripheral oedema, coagulation disorders, poor peripheral circulation and need for high volumes and doses).
IV administration is an option for opioid titration when rapid pain control is needed.
Scheduling and titration
Individual titration, eg, normal-release morphine administered every four hours plus rescue doses (up to hourly) for breakthrough cancer pain (BTcP), is recommended in clinical practice.
Immediate and slow-release oral morphine formulations can be used to titrate the dose. Titration schemes for both types of formulation should be supplemented with immediate-release oral opioids, prescribed as required for BTcP.
The regular dose of slow-release opioids can be adjusted to take into account the total amount of rescue morphine.
Management of opioid side-effects
Laxatives must be routinely prescribed for both the prophylaxis and the management of opioid-induced constipation (OIC)
The use of naloxone (in association with oxycodone) or methylnaltrexone to control OIC may be considered.
Naloxegol has been shown to be highly effective in OIC, but, to date, there is no specific reported experience in the cancer population.
Metoclopramide and antidopaminergic drugs should be recommended for treatment of opioid-related nausea/vomiting.
Psychostimulants (eg, methylphenidate) to treat opioid-induced sedation are only advised when other methods to treat this have been tried (eg, if it is not possible to rationalise all medication with a sedative side-effect).
Mu receptor antagonists (eg, naloxone) must be used promptly in the treatment of opioid-induced respiratory depression.