Cancer Pain

Question 1

A 63-year-old gentleman presents to the pain clinic with severe pain. He has
recently been diagnosed with metastatic pancreatic cancer.

What are the potential causes of pain in this patient?

Answer 1

• Pre-existing comorbidities or chronic pain condition.
• Direct pain from the tumour-causing inflammation and oedema of
  the surrounding structures.
• Pain due to treatment (side effect of chemotherapy or radiotherapy, or postoperative pain).
• Pain arising due to complications of the cancer diagnosis e.g. osteoporosis/bone pain.

Question 2

What is your approach in the assessment of this patient?

Answer 2

• A biopsychosocial approach should be taken to carefully assess the patient’s pain.
• A full and thorough history of the patient’s pain is required to determine the onset, location, type of pain and effect on the patient’s life. This should be followed by the appropriate examinations and investigations.
• Pain management should be multidisciplinary, taking into account the prognosis of the patient and the likely causes of his pain. This should include oncologists, surgeons, palliative care and the acute and chronic pain teams where appropriate.
• The pain is likely to be exacerbated by psychological factors, necessitating an empathetic and holistic approach.

Question 3

The patient describes severe abdominal and back pain that is worse at night.

What are his analgesic options?

Answer 3

Pharmacological:
* Simple analgesia: regular paracetamol and NSAIDs.

• Opioids: modified release morphine with immediate release agents for breakthrough pain should be considered early given this patient’s severe pain and likely terminal diagnosis. The dose should be titrated carefully to minimise unpleasant side effects. If the patient is palliative, these agents can often be given through a syringe driver.
• Antidepressants or anti-convulsants if there is a neuropathic element
  to pain.
• Steroids can be used successfully in the management of cancer pain
  that occurs due to stretching of viscera and local structures. These are often also used following radiotherapy.
• Chemotherapy can lead to a decrease in pain by its direct effect on tumours.
• If the back pain is due to bony metastases, bisphosphonates may be used to target these lesions.

Question 4

What are his analgesic options?

Continued…

Answer 4

Interventional:
* Surgery is a potential, but probably unlikely consideration in this patient due to spread of the disease. However, interventions such as stenting may help alleviate painful and uncomfortable symptoms.

• Radiotherapy may be used to target bony metastases.
• Targeted nerve destruction – coeliac plexus blockade.
• Intrathecal drug delivery may also be considered.

Question 5

What are the side effects of opioid-based agents?

Answer 5

• Sedation.
• Constipation.
• Nausea/vomiting.
• Pruritus.
• Urinary retention.
• Respiratory depression.
• Worsening of pain (opioid-induced hyperalgesia).
• Myoclonic jerks at very high levels.

Question 6

What are the complications associated with a coeliac plexus block?

Answer 6

• Hypotension.
• Diarrhoea.
• Major vessel injury (aorta/vena cava) and catastrophic haemorrhage.
• Intravascular injection/local anaesthetic toxicity.
• Damage to abdominal organs.
• Paralysis.
• Sexual dysfunction.