Dr Paul Cormie summarises the recommendations relevant to primary care from SIGN on the assessment and management of severe pain in patients with cancer
Management of pain is a common aspect of general practice. However, management of severe pain, particularly cancer-related pain, can be especially challenging.
Surveys reveal that the effectiveness of pain control in patients with cancer varies, with 12–51% of patients reporting unsatisfactory pain control.1,2 Uncontrolled pain limits a person’s ability to self-care, affects their response to illness, and reduces their quality of life.3
In primary care it is possible to control pain in the majority of patients with cancer by following pain-management guidelines such as the SIGN guideline.3 In a small proportion of patients, satisfactory pain control will not be achieved; such patients should be rapidly referred to specialist palliative care.
Who should assess pain?
Healthcare professionals have been shown to underestimate the level of pain a patient experiences and family members tend to overestimate pain in their relatives. Patients are the most reliable assessors of their own pain.4
How should pain be assessed?
The GP or district nurse should perform a full pain assessment. This comprises history, examination, relevant investigations, and the use of standardised assessment tools. The assessment should enable a diagnosis of the cause of the pain (cancer, cancer treatment, or non-cancer), and its functional and psychosocial impact.3
Pain assessment should be carried out regularly, at least daily when pain is not adequately controlled.3 Of the many different assessment tools available, none are universally accepted. Visual analogue scales (VAS), numerical rating scales (NRS), and verbal rating scales (VRS)5 are all valid tools used to measure pain and are applicable to patients with cognitive impairment, the very elderly, or patients in the dying phase. The effects of treatment should be monitored with these scales.3
Box 1: Pain assessment3
|Scottish Intercollegiate Guidelines Network. Control of pain in adults with cancer. A national clinical guideline. SIGN 106. Edinburgh: SIGN, 2008. Reproduced with kind permission of the Scottish Intercollegiate Guidelines Network|
Good communication between healthcare professionals, patients, and carers is important to assess pain accurately and improve compliance with treatment.3
Cancer can destabilise patients’ lives in terms of their self-identity, belief systems, and place in the world. Patients value professionals who adopt a holistic approach to care, and who deal competently with (and are able to communicate about) the spiritual, psychological, and emotional impact of pain.3
Psychological factors can profoundly influence the perception of pain and how the sufferer responds behaviourally and emotionally. It is, therefore, important to screen for anxiety and depression as part of a comprehensive pain assessment. Screening for psychological distress should be carried out using a validated tool3 such as the Patient Health Questionnaire-9, Brief Pain Inventory,6 or Hospital Anxiety and Depression Scale.7
Cognitive behaviour therapy has been shown to improve quality of life and reduce distress in those with cancer-related pain.8 It should be part of a comprehensive treatment programme for those with cancer-related pain who have associated distress and disability.3
Types of cancer pain
Cancer pains may be divided broadly into two types:9
- nociceptive, which results from tissue injury
- neuropathic, which results from damage to the peripheral or central nervous system.
Breakthrough pain is a transient flare of pain of moderate or severe intensity that arises from a background of controlled chronic pain.3 It may be subdivided into:
- spontaneous (unexpected) pain
- incident pain (expected or predictable), such as pain precipitated by weight bearing or movement in patients with bone metastases.
The distinction is important because breakthrough-pain medication may be taken in anticipation of an activity that is likely to precipitate pain (e.g. dressing, walking, or having a wound changed). It is associated with poor functional capacity and worse psychological outcomes. It may occur when pain at rest is controlled well and can present a difficult, but important management challenge.
Treatment of pain
For patients at all stages of the World Health Organization (WHO) analgesic ladder (see Figure 1),10 paracetamol and/or a non-steroidal anti-inflammatory drug should be prescribed regularly unless contraindicated. When used with opioids, the effect of these drugs may be synergistic, and so produce better pain relief at lower doses of opioids, potentially with fewer opioid side-effects.
Adjuvant analgesics are drugs with other primary indications that can be effective analgesics in specific circumstances (e.g. steroids, anticonvulsants, tricyclic antidepressants):3
- bisphosphonates have a role in addition to analgesics and/or radiotherapy to treat pain in patients with metastatic bone disease
- a tricyclic antidepressant (e.g. amitriptyline) or anticonvulsant (e.g. gabapentin) should be prescribed for patients with neuropathic pain, but side-effects should be monitored carefully.
Pharmacological treatment with opioids
The opioid is chosen according to the level of pain (see Figure 1):
- for moderate pain (step 2 of the WHO ladder, score 3–6 out of 10 on VAS or NRS), prescribe weak opioids such as codeine 60 mg four-times daily
- for severe pain (step 3 of the WHO ladder, score >6 out of 10 on VAS or NRS), prescribe morphine as the first-line oral therapy and diamorphine as the first-line subcutaneous therapy; other options include hydromorphone, oxycodone, and transdermal fentanyl.3
Morphine is the oral opioid of choice for control of severe cancer pain. It is available in immediate-release (IR) liquid and tablet formulations and modified-release (MR) capsules and tablets that can be taken once or twice daily.
Immediate-release (IR) morphine formulations have an onset of action of about 20 minutes and reach peak drug levels at 60 minutes (on average). These preparations must be given every 4 hours to maintain constant analgesic levels and will reach a steady plasma concentration, and hence full effect within 12–15 hours. In practice, during titration, dose adjustments are usually made every 24 hours unless the pain is more severe, in which case adjustments may be made after a shorter period.3
Initiating and titrating morphine
When a patient is first started on morphine, treatment should start with IR oral morphine 5–10 mg every 4 hours in young and middle-aged patients and 2.5–5 mg every 4 hours in elderly patients.3 Extra doses of the same amount are prescribed for breakthrough pain as often as necessary. Everyday, an assessment should be made of the patient’s pain, any side-effects, and the total amount of morphine required, including breakthrough doses. If breakthrough doses have been required then the regular 4-hourly dose is increased to account for this, for example:
- 10 mg morphine IR every 4 hours and three breakthrough doses = 60 mg + 30 mg = 90 mg daily. So the prescription for morphine should be rewritten as IR 15 mg 4-hourly and 15 mg for breakthrough.
Care should be taken when calculating new regular doses for patients who are pain free at rest, but who have pain on movement (incident pain). If all the analgesia for this pain is incorporated into the new, regular morphine dose, such patients receive more morphine than is required for their background pain, and this excess may cause drowsiness at rest and possibly opioid toxicity. This is because pain is a physiological antagonist to the sedative and respiratory depressant side-effects of opioids.
When the pain is well controlled, the IR 4-hourly morphine may be converted into a twice-daily MR tablet or capsule. Immediate-release morphine must still be available for breakthrough pain, for example:
- 20 mg morphine IR every 4 hours = 60 mg morphine MR twice daily and 20 mg morphine IR for breakthrough.
The GP should prescribe breakthrough analgesia in the form of an IR strong opioid for all patients with moderate or severe pain on a strong opioid. When oral morphine is used for breakthrough pain, the dose should be one-sixth of the total morphine dose over 24 hours, and then increased appropriately when the total dose is increased.
Patients with renal impairment
Poor renal function is common in palliative care. Different opioids are metabolised and excreted in different ways and so some opioids are much more likely to cause toxicity than are others:
- opioids should be used with caution and at reduced doses and/or frequency. Alfentanyl, buprenorphine, and fentanyl are the safest opioids
in patients with chronic kidney disease stages 4 or 5 (estimated glomerular filtration rate [eGFR]<30 ml/min/1.73 m2)3,11,12
- specialist palliative-care advice should be sought for the appropriate choice, dosage, and route of opioids.
Switching between strong opioids
Although morphine and diamorphine are the first-line strong opioids for the control of cancer pain, sometimes, despite dose titration, pain relief is inadequate and/or the side-effects can be so troublesome that an alternative opioid needs to be tried. This is termed opioid switching.
Before switching opioids, a full reassessment of the patient should be carried out and the following should be considered:
- are the presumed ‘opioid side effects’ caused by the drug, the cancer, or another factor?
- are non-opioids being prescribed?
- are adjuvant analgesics being prescribed (where appropriate)?
This is often a complex situation for which discussion with specialist colleagues is indicated. Information on alternative opioids and conversion ratios between different opioids is given in the full guideline.3
Laxatives should be prescribed for all patients who take opioids and the dose adjusted according to the patient’s bowel habit.
Other treatment options
Difficult-to-control pain should be discussed with the local specialist palliative-care service. Options include:3
- alternative opioids
- other drugs such as ketamine
- radiotherapy and specialist orthopaedic interventions for bone pain
- anaesthetic interventions such as nerve blocks or epidural opioid infusions.
Figure 1: Adaptation of the WHO analgesic ladder to show analgesic treatment options3,10
*Non-opioids and adjuvants can be used at any step.
WHO=World Health Organization; NRS=numerical rating scales; NSAIDs=non-steroidal anti-inflammatory drugs
Caring for patients with cancer pain can be both challenging and extremely rewarding. Many patients in the palliative phase of their illness express a wish to be cared for at home in the last days and weeks of their illness. The primary care team has a crucial role to play in providing support, care, and relief from symptoms such as pain. By following a guideline on pain management, such as SIGN 106,3 it is possible for the team to achieve satisfactory pain control in the majority of patients.
Practice-based commissioning take home message
written by Dr David Jenner, NHS Alliance GMS contract/PBC Lead
|1Department of Health. Transforming community services: enabling new patterns of provision. London: DH, 2009|
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the SIGN guideline on cancer pain in adults
- Zech D, Grond S, Lynch J et al. Validation of World Health Organization guidelines for cancer pain relief: a 10-year prospective study. Pain 1995; 63 (1): 65–76.
- Larue F, Colleau S, Brasseur L, Cleeland C. Multicentre study of cancer pain and its treatment in France. BMJ 1995; 310 (6986): 1034–1037.
- Scottish Intercollegiate Guidelines Network. Control of pain in adults with cancer. SIGN 106. SIGN: Edinburgh, 2008.
- Cleeland C, Gonin R, Hatfield A et al. Pain and its treatment in outpatients with metastatic cancer. N Engl J Med 1994; 330 (9): 592–596.
- Caraceni A, Cherny N, Fainsinger R et al. Pain measurement tools and methods in clinical research in palliative care: recommendations of an expert working group of the European Association of Palliative Care. J Pain Symptom Manage 2002; 23 (3): 239–255.
- Duat R, Cleeland C, Flannery R. Development of the Wisconsin Brief Pain Questionnaire to assess pain in cancer and other diseases. Pain 1983; 17 (2): 197–210.
- Walker J, Postma K, McHugh G et al. Performance of the Hospital Anxiety and Depression Scale as a screening tool for major depressive disorder in cancer patients. J Psychosom Res 2007: 63: 83–91.
- Graves K. Social cognitive theory and cancer patients’ quality of life: a meta-analysis of psychosocial intervention components. Health Psycho 2003; 22 (2): 210–219.
- Watson M, Lucas C, Hoy A, Back I. Oxford handbook of palliative care. Oxford: Oxford University Press, 2005.
- World Health Organization.Cancer pain relief, 2nd ed. Geneva: WHO, 1996.
- Mercadante S, Arcuri E. Opioids and renal function. J Pain 2004; 5 (1): 2–19.
- Launay-Vacher V, Karie S, Fau J et al. Treatment of pain in patients with renal insufficiency: The World Health Organization three-step ladder adapted. J Pain 2005; 6 (3): 137–148.G