Classification of Cancer Pain Syndromes

Classification of Cancer Pain Syndromes

Chronic pain occurs in about one-third of all cancer
patients and in about three-quarters of those with advanced disease.[1] A major
factor in the undertreatment of cancer pain is inadequate pain assessment.[2]
Pain assessment provides the basis for inferred pathophysiology that directs
diagnostic evaluation and treatment decisions. Pain syndrome identification
plays an important role in this process—much of clinical medicine is based on
pattern recognition of symptoms and signs, leading to a specific diagnosis and
therapeutic strategy.

Provocative maneuvers that reproduce pain are especially valuable. For
example, a positive femoral stretch test or reverse straight-leg-raising
maneuver can reproduce back pain and lead the clinician to investigate further
for a retroperitoneal mass.

Classification of Pain Syndromes

In this issue of ONCOLOGY, Drs. Caraceni and Weinstein provide a
comprehensive review of the classification of cancer pain syndromes. Although
they describe several classification schemes, syndromic classification including
underlying pathophysiology probably provides the most useful clinical

Foley’s seminal work in cancer pain syndrome identification is still useful
today.[3] For instance, impending epidural spinal cord compression can be
recognized by localized spinal pain followed by radicular pain. The inferred
pathophysiology is somatic pain due to vertebral body metastasis, followed by
neuropathic pain due to infiltration of the adjacent nerve roots. Recognition
and appropriate treatment of this syndrome can prevent a neurologic catastrophe.

Similarly, postmastectomy pain usually presents in a highly stereotypical
manner. The pain is typical of neuropathic pain with a burning, stabbing
component; it is localized to the axilla, upper inner arm, and chest wall, and
usually persists beyond the normal healing time of 3 months. Recognition of this
pain syndrome as treatment- related pain rather than due to cancer progression
provides valuable prognostic information.

A recent retrospective cohort study of postmastectomy pain syndrome
challenged the traditional view that this is an uncommon condition, finding a
prevalence rate of 29%.[4] Crystallization of pain syndromes as distinct
clinical entities provides a basis for large-scale epidemiologic studies to
further define the prevalence of disease- and treatment-related conditions.
However, this is complicated by the observation that patients often present with
multiple pain syndromes that are due to both disease progression and treatment.


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