Cancer pain is a multidimensional phenomenon. The source of pain may be from cancer progression itself, from associated treatments, or from non-cancer related pain generators for example arthritis or radicular pain. Regardless of the reason, pain can significantly impact on patients’ quality of life, cause psychological distress, and lead to functional limitations.
While pharmacological approaches generally are the first line of treatment in cancer pain management, interventional techniques are a valuable tool to help reduce pain and improve dignity and quality of life.
Indications for interventional techniques
Refractory pain: When pain persists despite optimal pharmacological treatment.
Intolerance to medications: When systemic analgesics cause intolerable or uncontrolled side effects.
Decline in quality of life: While pain killers may produce an effective pain control, they may lead to cognitive bluntness, reduced ability to interact with the loved ones or increased need for support and care which may not be desirable.
Common pain interventions
Neurolytic Blocks are procedures where alcohol or phenol is used to abolish nerve function. Coeliac Plexus Block is used for upper abdominal malignancies such as pancreatic cancer. Superior Hypogastric Plexus Block for gynaecological and pelvic organ cancer. Lumbar sympathectomies for lower limb ischaemia. Intrathecal neurolysis for rectal and pelvic cancer.
Intrathecal Drug Delivery Systems are one of the most effective techniques to control wider spread pain from cancer. A catheter is inserted inside the thecal space, at the desired level of the spinal cord, to cover the dermatomes responsible for the painful area.
A connected pump delivers a range of medications, usually local anaesthetics (LA), opioids (morphine, hydromorphone) with or without adjuncts (clonidine). LA blocks pain signal propagation, opioids work on central nervous system mu receptors and clonidine helps with desensitisation. The combined effect can produce significant pain reduction, allowing to reduce, even to stop most of the systemic analgesia. This technique requires access to a trained nursing team in the community and generally is offered in terminal stages of cancer.
Neuro-ablation (Pulsed or Thermal radiofrequency denervation, Cryo-ablation,) uses a variety of techniques to modulate neural tissue activity or ablate/denervate nerves to prevent pain signal propagation. As an example, in metastatic rib lesions, cryo-ablation of subcostal nerves can reduce pain. Pulsed rhizotomy of peripheral nerves can reduce neuropathic pain secondary from radiotherapy.
I recently utilised thermal rhizotomy effectively to address pain from a metastatic lesion in the spinous process. I have combined thermal and pulsed rhizotomy in a case with localised shoulder cancer, preventing recurrent hospitalisations for pain management.
Hence, this technique can be utilised in number of different scenarios depending on the location of the lesion, the cause of the pain and the nerve supply.
Vertebroplasty – Metastatic vertebral body fractures unresponsive to analgesia can respond very well by injecting bone cement into the fractured vertebral body.
Epidural injection, nerve root sleeve injection and dorsal root ganglion pulsed rhizotomy aim to deposit medications around the neural tissue to diminish localised inflammation or to modulate their function. Examples would be nerve irritation from cancer tissue compressing spinal nerves or neuritis from chemo or radiotherapy.
Peripheral nerve block and regional catheter is most commonly used for a neck of femur fracture or a paravertebral catheter for rib fractures. This is generally a short-term measure to control the pain while the patient is awaiting definite treatment.
Spinal Cord Stimulation (SCS) is an advanced technique for managing neuropathic pain. It works by delivering electrical impulses to the dorsal column of the spinal cord providing pain modulation. Its efficacy has been established in chronic pain and its role is emerging in cancer pain, though the data is limited.
Cervical cordotomy – a thermal neuro-ablation of lateral spinothalamic tract at the level of C1/2 of the spinal cord would abolish the pain arising from contralateral body. It is generally used for chest wall pain such as mesothelioma.
While the above examples are modalities to help cancer-related pain, it is important to note that cancer patients may present with non-cancer related pain.
For example, knee arthritis, facet joint disease or sacroiliac arthralgia. Considering that the majority of cancer patients would be already on some form of analgesia for their cancer treatment, interventional pain technique can play an important role to help with their non-cancer related pain generators.
Key messages
- Interventional pain techniques can be very useful in managing cancer pain
- Cancer patients may have non-cancer related pain which can respond to injections
- Interventional pain techniques can help reducing polypharmacy, their side effects and improve quality of life in cancer patients.
Author competing interests – nil
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