PAIN IN CANCER AN OVERVIEW

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PAIN IN CANCER AN OVERVIEW

• Dr. Suresh Kumar
• Institute of Palliative Medicine
• Kerala, India

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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 STUDY OF PAIN)

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A simple definition

• Pain is what a person says it hurts.

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Pain in cancer

• Incidence of pain at various stages of cancer
  disease trajectory is approximately 50
• This increases to approximately 80 in advanced
  cancer

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Pain in cancer

• Most patients with advanced cancer have two or
  more types of cancer related pain sometimes with
  different etiologies

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Pain in cancer

• 90 of cancer pain could be effectively
  controlled using the WHO guidelines
• Cancer pain is often under diagnosed and under
  treated

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Assessment of pain

• Inadequate pain assessment is an important
  contributing factor in the under treatment of pain

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Why assess pain

• Assess efficacy of therapy
• Better understanding of pain
• Encouragement, support
• Future reference

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Measurement of pain

• Unidimensional
• Numeric Rating Scale
• Verbal Rating Scale
• Visual Analog Scale
• Verbal Descriptor scales
• Faces Pain Rating Scale

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Multidimensional Instruments

• McGill Pain Questionnaire
• Brief Pain Inventory
• Multidimensional Pain Inventory

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Numeric Scale
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Simple Descriptive Scale
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Visual Analogue Scale The VAS for Pain severity
measurement No Pain
Worst

Possible Pain The VAS for
Treatment Effect No Pain
Complete
Pain Relief
Relief

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VAS Coloured Analogue Scale
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Classification of Pain
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Acute Chronic Pain

• Acute pain
• Well defined temporal pain onset
• Associated with
• subjective and objective physical signs
• Hyper activity of ANS
• Increased BMR
• Helps in limiting the damage

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Acute Chronic Pain

• Chronic pain
• Pain persisting for 3 months
• Less well defined temporal onset
• Adaptation of ANS, lack of objective signs
• Changes in personality, lifestyle, functional
  ability
• No known useful biological purpose

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Causes of Pain in Cancer

• Directly due to cancer
• Soft tissue infiltration
• Bone involvement
• Nerve infiltration / compression
• Visceral pain
• Muscle spasm

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Causes of Pain in Cancer

• Due to treatment
• Surgery
• Direct
• Scar
• Radiotherapy
• Fibrosis
• Mucositis
• Chemotherapy
• Neuropathy

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Causes of Pain in Cancer

• Due to associated factors
• Pressure sores
• Constipation
• Bladder spasm
• Stiff joints
• PHN

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Causes of Pain in Cancer

• Unrelated causes
• LBA
• Trauma
• Arthritis
• Angina
• Emotional factors

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Management of cancer pain

• In 90 of patients, analgesia achieved with drug
  therapy
• - By mouth
• - By the clock
• - By the ladder

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Steady state plasma concentration (Css) When all
the trough and peak concentrations do not vary
drugconcentration
Time
(Roughly take 4 half lives to reach 95 Css )
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WHO Analgesic Ladder

• Strong opioid
• Step 1
• Weak opioid
• Step 1
• Non opioid
• adjuvants

Step 3
Step 2
Step 1
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Non Opioids

• NSAIDs
• Paracetamol

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NSAIDS Mode of action

• suppression of prostaglandin synthesis at sites
  of tissue injury
• modulation of the neutrophil intracellular
  signaling function (?migration of neutrophils to
  inflammatory sites)

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NSAIDs Adverse effects

• GI toxicity
• Renal toxicity
• Interference with platelet function

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Use of NSAIDS

• it is recommended that NSAIDs be used
• at the lowest effective dose
• for the shortest duration of time necessary
• especially in patients
• over the age of 65 years,
• those taking oral corticosteroids, and
• those treated with anticoagulants.

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Opioids

• The division into weak or strong only for our
  convenience
• Weak opioids
• Codeine
• Dextropropoxyphene
• Pentazocine
• Tramadol

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Strong opioids

• Morphine
• Pethidine
• Fentanyl
• Oxycodone
• Hydromorphone

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Opioid side effects

• Constipation 99
• Nausea, vomiting 33
• Sleepiness, tiredness 33
• Urinary hesitancy 5
• Itching 5

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Signs of overdose

• Drowsiness
• Delirium
• Myoclonus
• Respiratory depression??

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Adjuvants

• To limit the side effects
• of analgesics
• Co - analgesics

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Co - analgesics

• Steroids
• Anti depressants
• Anti epileptics
• Anti arrythmics
• NMDA receptor antagonists

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Treatment of Cancer pain Summary

• Assess properly before deciding on a management
  scheme

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Treatment of Cancer pain Summary
Identify the cause of pain before treatment
Think of multiple causes!!
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Treatment of Cancer pain Summary

• Decide on the pharmacological strategy
• Work within the WHO Ladder

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Treatment of Cancer pain Summary

• Remember supportive measures
• Combine pain relief with
• relief from other symptoms
• emotional and social support

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Pain not responding to WHO ladder

• Possible causes are
• The prescriber!
• The patient!
• The pain

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Prescriber as a cause for difficult pain

• Are the basic prescribing guidelines being
  followed?
• Is the WHO ladder being used properly?
• Has the dose of opioid titrated up according to
  clinical response?
• Is the dose and dosing interval correct?
• Have co analgesics and other interventions been
  used appropriately?

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The patient as a cause for difficult pain

• Is the patient taking medication as prescribed?
• Are there fears/ concerns being addressed?
• Is there co existing depression?
• Does the pain have a significant psycho social or
  spiritual component?

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The nature of pain itself as a cause for
difficult pain

• Is it a neuropathic pain?
• Is it a colic?
• Is it a muscle spasm?
• Is it a pain from an ulcer?
• Is it incident pain?

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Thank You!