4.5 Pain relief in cancer

Question 1

a) List the causes of pain in a patient with advanced cancer.

Answer 1

Nerve pain
Tumour compression on nerve

Invasion
Tumour invading on organs

Pathological #
bony mets causing #

malignant pleural effusions causing pleuritic pain

Cancer pain may be nociceptive, neuropathic or mixed
(most common).

Causes can be:
● Cancer-related:

• local mass effect on neural and non-neural tissues
  including bone inflammation,
  tissue invasion, ischaemia, compression, oedema;
• paraneoplastic syndromes releasing anti-neuronal antibodies —
  leading to mononeuritis/polyneuritis and peripheral neuropathy.

_______

● Cancer treatment-related:
- chemotherapy-induced peripheral neuropathy;

• radiation-induced neuropathic pain;
• acute and chronic post-surgical pain.

_________

● Associated condition-related:

• immobilisation-related pain;
• infection;
• reactivation of Herpes zoster by immunosuppression.

Question 2

b) How can side effects from opioid medications be minimised in
these patients?

Answer 2

● Use of non-opioids for analgesia,
especially in the initial stages
— opioid-sparing agents.

● Reduce the dose of opioids
— start on a low dose for opioids and
gradually titrate to build up the dose.

● Symptomatic management of side effects
like pruritis and constipation.

● Opioid rotation —
change of opioids considering their equianalgesic doses of other opioids.
Always start at a half to two thirds of the
calculated equianalgesic dose of opioids.

● Administration of specific antagonists,
e.g. oral naloxone for opioid induced constipation

Question 3

c) List the steps in the WHO analgesic ladder for cancer pain.

Answer 3

Step 1:
● Non-opioids +/- adjuvants.
● Paracetamol.
● NSAIDs with adjuvants like gabapentinoids.
● Bisphosphonates.
● Steroids.
● Tricyclics.

Step 2:
● Weak opioids
(codeine, dihydrocodeine and tramadol)
+ non-opioid +/- adjuvants.

Step 3:
● Strong opioids
(morphine, oxycodone, fentanyl)
+ non-opioids
+/- adjuvants.

Question 4

d) What is the most commonly used class of drug used for the
management of cancer pain and in what manner are they used
to optimise their effect?

Answer 4

Opioids are the most commonly used class of drugs for pain relief in cancer.

Opioids are used for:
● ‘Background’ analgesia —
provided by long-acting opioids.

● ‘Break-through’ pain management —
achieved by intermittent doses
of short-acting opioids

Question 5

e) Give three examples of interventional strategies, along with
their indications, done by pain specialists to manage cancer
pain.

Answer 5

● Coeliac plexus block —
for pancreatic cancer pain.

● Ganglion impar block —
for anorectal pain arising from local
malignancies, e.g. cancer of the rectum
.
● Superior hypogastric plexus block —
for pelvic cancer pain syndromes.
Other examples are:

● Peripheral nerve blocks, e.g. intercostal nerve blocks.

● Neurolytic procedures — peripheral and intrathecal.

● Intrathecal drug delivery (ITDD) systems.

● Percutaneous cervical cordotomy