Cancer Pain Management

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Cancer Pain Management

• Dr Simon Chan
• Pain Management Unit
• Dept of Anaesthesia and Intensive Care
• Prince of Wales Hospital

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Pain - Definition

• an unpleasant sensory and emotional
  experience associated with actual or potential
  tissue damage or described in terms of such
  damage
• International Association for the Study of Pain
• Pain is biological useful because it signals
  injury or disease

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Outlines

• Pathophysiology of cancer pain
• Mechanism of cancer pain
• Assessment of cancer pain
• Modalities of cancer pain management
• Clinical aspects of cancer pain management

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Outlines

• Pathophysiology of cancer pain
• Mechanism of cancer pain
• Assessment of cancer pain
• Modalities of cancer pain management
• Clinical aspects of cancer pain management

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Pathophysiology of Cancer Pain
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Pathophysiology of Cancer Pain

• Three main factors contribute to the pathogenesis
  pain in cancer patients
• Nociceptive pain
• Neuropathic mechanism
• Idiopathic (psychological) processes

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Nociceptive Pain

• Pain resulting from the activation of nociceptors
  in somatic or visceral structures
• Nociceptive somatic pain sharp, aching,
  throbbing or pressure-like
• Visceral pain poorly localized
• Hollow viscus cramping
• Solid organ capsule or mesentery sharp, aching
• Responds well to all forms of analgesia

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Neuropathic Mechanism

• Results from abnormal functioning in the central
  or peripheral somatosensory system
• Associated with dysesthesia, allodynia,
  hyperalgesia
• Pain burning or stabbing
• Due to nerve lesion, surgery, chemo
• Variable response to opioid

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Idiopathic Pain

• Pain that is not explained with the organic
  pathology
• Diagnosed with extreme caution
• Onset of symptoms could be long before imaging
  proven tumor growth

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Outlines

• Pathophysiology of cancer pain
• Mechanism of cancer pain
• Assessment of cancer pain
• Modalities of cancer pain management
• Clinical aspects of cancer pain management

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Mechanism of Cancer Pain
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Mechanism of Cancer Pain

• Pain syndrome related to direct tumor involvement
• Pain syndrome due to cancer treatment

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Direct Tumor Involvement

• Infiltration of bone and joints
• Commonly seen in Ca breast, lung, prostate
• Pain usually localized, mechanical
• Vertebral pain syndrome
• Tumor infiltration of viscera
• Distention of solid organ capsule
• Obstruction of hollow viscus GI, biliary,
  ureter
• Direct tissue infiltration pleura, peritoneum

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Direct Tumor Involvement

• Tumor infiltration of soft tissue
• Skin, subcutaneous tissue, muscle
• Compression of nervous tissues
• Peripheral nerve, plexus, spinal cord
• Tumor-related headache
• Skull lesion, ? ICP

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Pain Related to Cancer Treatment

• Post-surgical
• Surgical trauma, non-healing incision
• Neuropathic mastectomy, thoracotomy, limb
  amputation
• Postradiotherapy syndrome
• Inflammation of mucous membrane, fibrosis,
  osteoradionecrosis, myelopathy
• Post-chemotherapy
• Polyneuropathy, aseptic bone necrosis

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Outlines

• Pathophysiology of cancer pain
• Mechanism of cancer pain
• Assessment of cancer pain
• Modalities of cancer pain management
• Clinical aspects of cancer pain management

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Assessment of Cancer Pain
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Assessment of Cancer Pain (1)

• Multi-dimensional assessment
• Believe the patients complaint of pain
• Take a detail pain history
• Evaluate the response to previous and current
  analgesic therapies
• Evaluate the psychological state of the patient
• Physical and neurological examination

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Assessment of Cancer Pain (2)

• Appropriate diagnostic tests
• Design the diagnostic and therapeutic approach to
  suit individual patient
• Reassess the response to pain therapy regularly
• Discuss advance directives with patients and
  family

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Outlines

• Pathophysiology of cancer pain
• Mechanism of cancer pain
• Assessment of cancer pain
• Modalities of cancer pain management
• Clinical aspects of cancer pain management

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Different Modalities of Pain Management

• Pharmacological analgesia
• Physical therapy
• Psychotherapy
• Interventional neural blockade
• Neuro-ablation - surgical, percutaneous
• Neuro-augmentation - dorsal column stimulation
• Anti-cancer treatment

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Physical Therapy

• Therapeutic heat superficial, short-wave
  diathermy, ultrasound
• Therapeutic cold
• Transcutaneous electrical nerve stimulation
• Biofeedback and acupunture
• Therapeutic exercise strengthening, stretching,
  postural and relaxation exercise
• Mobilization traction, manipulation, massage
• Hydrotherapy

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Psychotherapy

• Relaxation training
• Behavioral therapy aim to reduce pain behaviour
• Cognitive restructuring to replace the
  maladaptive themes with more adaptive thoughts
• Others group, marital, family therapy and
  hypnosis

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Outlines

• Pathophysiology of cancer pain
• Mechanism of cancer pain
• Assessment of cancer pain
• Modalities of cancer pain management
• Clinical aspects of cancer pain management

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Pharmacological Analgesia in Cancer Pain

• Appropriate drug for the cause of pain
• WHOs analgesic ladder
• Round the clock
• Oral route as the preferred route (alternate
  route if intolerant or side effects)
• Individualize dosage
• Anticipate side effects

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WHO Analgesic Ladder
Potent opioid
Weak opioid
Simple analgesia
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Non-Narcotic (Adjuvant) Analgesia

• Simple analgesia
• paracetamol
• NSAIDs
• musculoskeletal pain
• side effects
• Anti-depressants
• descending modulating pathway
• neuropathic pain

• Anti-convulsants
• neuropathic pain
• Membrane stabilizer
• neuropathic pain
• Muscle relaxant
• Baclofen

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Opioid Analgesia

• Choice of opioid
• potent vs weak
• side effect profile
• pharmacokinetic properties
• Route of administration
• Systemic - IV, IM, PCA
• Oral
• Spinal - epidural, intrathecal
• Novel route

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Patient-Controlled Analgesia PCA Pumps

• Technological Improvements
• Smaller
• More ambulatory
• Battery life
• Memory

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Patient-Controlled Analgesia PCA Pumps

• Technological Improvements
• Smaller
• More ambulatory
• Battery life
• Memory

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Common Side Effects of Opioid

• Sedation
• Nausea and vomiting
• Constipation
• Urinary retention
• Pruritus
• Reactivation of herpes simplex

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Opioid Responsiveness

• Defined as the probability that adequate
  analgesia (satisfactory relief without
  intolerable and unmanageable side effects) can be
  attained during gradual dose titration.
• ie degree of analgesia obtained at
  treatment-limiting toxicity

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Strategies for Poor Opioid Responsiveness

• Opening the therapeutic window
• Aggressive side effect treatment, eg
  psychostimulant for sedation
• Opioid rotation
• Pharmacological techniques to reduce the systemic
  opioid requirement
• Adjuvant analgesia
• Neuraxial drug administration
• Interventional neural blockade

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WHO Analgesic Ladder
Interventional Neural Blockade
Potent opioid
Weak opioid
Simple analgesia
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Neuro-Ablation

• Percutaneous
• chemical
• radio-frequency
• Cryoanalgesia
• Neurosurgical

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Interventional Neural Blockade

• Peripheral nerve blockade
• diagnostic
• prognostic before neuro-ablation
• therapeutic
• Visceral denervation
• Spinal administration of drugs
• Chemical sympathectomy

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Epidural Analgesia

• Agents - LA, opioid
• Avoid side effects of systemic opioid

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Spinal Opioid

• Systemic epidural intrathecal 30101
• Pharmacological side effects
• delayed respiratory depression
• urinary retention
• pruritus
• herpes simplex
• systemic side effects

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Spinal Opioid - Mode of delivery

• intermittent vs continuous infusion
• patient control vs nurse control
• percutaneous vs implantable
• mechanical vs electronic pump

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Anti-Cancer Treatment

• Radiotherapy
• Intra-cranial lesion
• Bony metastasis for pain control and avoid spinal
  cord compression
• Chemotherapy
• Tumor shrinkage
• Steroid (dexamethasone)
• Reduce tissue swelling form tumor compression

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Multidisciplinary Approach to Pain Management

• Oncologist
• Palliative care physician
• Surgeon (Neurosurgeon, Orthopaedic)
• Nurse Pain, palliative care, community
• Physiotherapist
• Psychologist/ Psychiatrist
• Occupational therapist
• Anesthesiologist

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PAIN