Cancer Pain Syndromes
Craig D. Blinderman, MD, MA
Co-Director, MGH Cancer Pain Clinic
MGH Palliative Care Service
Objectives
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Review the definition of pain and basic
pathophysiology
Review the common causes of pain in cancer
patients
Review approach to managing pain
Defining Pain
Pain is defined as an unpleasant sensory and
emotional experience associated with actual or
potential tissue damage, or described in terms of
such damage.
Merskey, H., Bogduk, N, ed. Classification of Chronic Pain, Second Edition.
IASP Task Force on Taxonomy. 1994, IASP Press: Seattle. 209-214.
Taxonomy of Pain
• Classification may be based on:
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Anatomy
Body System
Temporal Characteristics
Severity
Etiology
Pathophysiology
 Defined pain syndromes
Taxonomy of Pain
Clinically, it is useful to determine both the etiology
and inferred pathophysiology in the assessment of
the pain complaint, as this may suggest the use of
specific therapies.
Taxonomy of Pain
• Nociceptive
 Somatic
 Visceral
• Neuropathic
• Psychogenic
• Idiopathic
Nociceptive Pain
• Nociceptive somatic pain
 Sustained predominantly by tissue injury or inflammation.
 Described as sharp, aching, stabbing, throbbing or pressure-like.
• Nociceptive visceral pain
 Poorly localized; described as crampy pain (e.g. obstruction of
hollow viscus), or as aching and stabbing (e.g. pain secondary to
splenomegaly).
Neuropathic Pain
• Sustained by abnormal somatosensory processing in
the PNS or CNS.
• Typically, described as “burning,” “shock-like,”
“electrical.”
• May be paroxysmal in nature.
• On physical examination, patients may have
allodynia (pain induced by non-painful stimuli) and
hyperalgesia (increased perception of painful stimuli).
Psychogenic Pain
• Refers to pain that is believed to be sustained
predominantly by psychological factors.
• Rare in the cancer population.
Idiopathic Pain
• In the absence of evidence sufficient to label pain as
either nociceptive or neuropathic, we may use the
term “idiopathic.”
• In patients with cancer, this term should lead to
additional workup and a search for an underlying
etiology and pathophysiology.
Basic Pathophysiology of Pain
Transduction
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Conversion of thermal, chemical, mechanical stimulus to electrical activity at nociceptor
 Na channels
Conduction
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Passage of action potential along the first order neuron to dorsal horn of spinal cord
Transmission
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Transfer and modulation of input from one neuron to another
 Substance P, Glutamate, Brain derived neurotropic factor
 Inhibitory interneurons
Perception
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Awareness and meaning of pain
Modulation
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Descending pathways inhibit transmission of nociceptive impulses
 e.g. Periaqueductal grey matter in midbrain-->nucleus raphae in medulla
 Norepinephrine, serotonin, endogenous opioids
Peripheral and Central Pathways for Pain
Ascending Tracts
Modulation
Descending pathways
inhibit transmission of
nociceptive impulses
Perception
Awareness and
meaning of pain
Transmission
Transfer and
modulation of input
from one neuron to
another
Descending Tracts
Cortex
Thalamus
Midbrain
Pons
Conduction
Passage of action
potential along the first
order neuron to dorsal
horn of spinal cord
Transduction
Conversion of thermal,
chemical, mechanical
stimulus to electrical
activity at nociceptor
Medulla
Spinal Cord
Cancer Pain Syndromes
Syndrome: Definition
• A temporal and qualitative convergence of symptoms
and signs, which conforms to a recognized pattern
• Associated with distinct etiologies, pathophysiologies,
and prognostic and therapeutic implications
Cancer Pain Syndromes
a) Related to tumor involvement
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Accounts for 78% of pain problems in inpatient cancer population and 62%
of outpatient cancer population in MSKCC survey
Metastatic bone disease, hollow viscous involvement and nerve
compression or infiltration are most common causes
b) Pain syndromes associated with cancer therapy
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19% of pain problems in inpatient population and 25% in outpatient
population
c) Pain unrelated to cancer or therapy
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Approx. 3% of inpatients have pain unrelated to their cancer and 10% in
outpatient population
d) Generalized pain in a dying cancer patient
Foley, KM. Pain syndromes in patients with cancer. Oxford Textbook of Palliative Medicine, 3rd Ed..
Cancer Pain Syndromes: Temporal Patterns
Temporal Classification
• Acute
• Chronic
• Breakthrough Pain
Acute Cancer Pain
• Defined by a recent onset and a natural history
characterized by transience.
• May or may not be associated with overt pain
behaviors.
• Usually caused by diagnostic or therapeutic
interventions
Causes of Acute Cancer Pain
•Diagnostic Interventions
•Acute postoperative pain
•Therapeutic interventions
•Analgesic Techniques
•Associated with chemotherapy
•Associated with radiotherapy
•Acute pain associated with
hormonal therapy
•Acute pain associated with
immunotherapy
•Acute pain associated with
infection
Chronic Cancer Pain
• Persists for one month or more beyond the usual course of
an acute illness or injury
• Most commonly due to direct effects of the tumor
• Other causes:
• Due to cancer therapy (15-25%)
• Pathology unrelated to either the cancer or its treatment (5-15%)
Causes of Chronic Cancer Pain
Related to tumor involvement
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Bone pain syndromes
Headache and Facial Pain
Tumor involvement of the peripheral nervous system
Visceral pain syndromes
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In neuroendocrine tumors with liver involvement this may be a major source of pain
Somatic soft tissue pain syndromes
Paraneoplastic pain syndromes
Pain syndromes associated with cancer therapy
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Post-chemotherapy pain syndromes
Chronic pain associated with hormonal therapy
Chronic post-surgical pain syndromes
Chronic post-radiation pain syndromes
Therapeutic strategy for cancer pain
•Non-pharmacological Modalities
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Cognitive behavioral interventions
Massage, Physical Therapy
Acupuncture
Cutaneous techniques
Radiation Therapy
Surgery
Interventional procedures
Anesthetic techniques
•Pharmacotherapy
 Non-opioid analgesics
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NSAIDs
Acetaminophen
Dipyrone
 Opioid analgesics
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Codeine
Morphine
Oxycodone
Fentanyl
Hydromorphone
Methadone
Levorphanol
 Adjuvant analgesics
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Anticonvulsants
Antidepressants
Local anesthetic agents
GABA agonists
NMDA antagonists
Others
Summary
• Cancer Pain may be due to the affects of the tumor
on viscera, nerves, bones and soft tissue.
• Acute and Chronic Pain syndromes may also be due
to the treatment of cancer
• Effective management of cancer pain requires
recognizing syndromes and their inferred
pathophysiology