Cancer Pain Syndromes

Classifwation of the Pain Patient
Additional perspective into the problem of
cancer pain is gained by a classification of
patient subtypes (Table 2). Patients with acute
cancer-related pain, either associated with the
diagnosis or with cancer therapy will endure an enormous amount of pain for promise of
successful outcome. Often, they do not seek
treatment and are able cognitively to manage
their pain without assistance. They tend to be
hopeful. In those successfully treated, acute
cancer-related pain may be viewed as a harbinger of illness; any recurrence of pain is an
immediate signal both to the patient and physician
that recurrent disease may be present.
The group of patients with chronic cancerrelated
pain have pain associated with either
progressive disease or with therap): These two
groups are of course very different. Those with
pain due to cancer therap); who have little or
no active disease, are often dealing with the
psychological components of their illness and
the need to re-establish a functional life. Their
attitude is in sharp contrast to the group of
patients who have progressive disease, in whom
hopelessness and helplessness may be overt.
A third important group with cancer pain
comprise those with pre-existing chronic pain.
The patient who has a long previous history of
chronic illness behavior must be identified
earl); They often need intensive intervention
and support, a continual focus on their psychological
status, and accurate diagnosis of their
cancer pain.
A fourth group of patients with pain
includ_es those who remain actively involved in
illicit drug use. This group is difficult to evaluate
and difficult to treat. Pain and cancer may
lead them to return to drugs to manage their
anxiety and depression. Their every complaint
is misinterpreted as a request for more drug.

Many of these patients must be taught the difi
ference between management of their behavior
and treatment of their pain. They may need to
be treated in a setting in which experts in rehabilitation
of the drug addict and experts in
pain management work together. They should
not be shunned or inadequately treated.
Lastl); there are the dying patients with
cancer-related pain. In this group, inadequate
management of pain has an enormous impact
on both the patient and family. Families suffer
greatly when a loved one dies in unrelieved
pain. This is what is remembered and what is
carried to the next fatal illness, either their own
or in their famil}: The impact of inadequate
pain control on bereavement is crucial in treating
this group of patients.
Pain Assessment
The principles of evaluating cancer pain are
shown in Table 3. One must clarify the complaint
of pain and distinguish between pain
and suffering. Understanding the extent of dis-
. *r ~ ease is crucial. It is ~mportant to examine where
the patient hurts and understand the referred
patterns of pain. If radiographs of the area of
pain do not appear to delineate any cause, the
physician should evaluate sites that may have
referred the pain. Diagnostic studies must be
reviewed personally. Appropriate analgesic
control must be maintained during all diagnostic
procedures.

Pain Syndromes
Specific pain syndromes (Table 4) occur in
the cancer patient. Syndromes associated with
infiltration of bone are the most common and
are often not recognized as early as they should
be. Involvement of the base of skull, the vertebral
bodies, and the sacrum represent the three major groups. In each group, patients present
with very typical symptomatolog): For example,
patients with disease at the C7 or T1 vertebral
body will complain of pain in tile paraspinal
area, which then radiates down the posterior
arm to the elbo~: They will then complain of
some paresthesias in the fourth and fifth fingers
of the hand and will eventually demonstrate
triceps weakness in the intrinsic muscles
of the hand. This characteristic syndrome
should be recognized before signs ofradiculopathy
develop.
There are typical pain syndromes that follow
direct infiltration of nerve. For example, nerve
compression in either the retroperitoneal or
the intercostal areas first present with pain,
with sensory and motor deficits developing
later. These patients may need evaluation of
contiguous structures. The CT scan and MRI
are the diagnostic procedures of choice.
A second group of patients with direct infiltration
of nerve are those who develop brachial
plexopath)~ Brachial plexopathy can occur in a
variety of different settings and from a variety
of different neoplasms, most often breast or
lung cancer, or .lymphoma. In a study of 100
patients with brachial plexopathy due to cancer,
78 patients demonstrated tumor infiltration,
of whom 82% presented with pain. Pain
was present for several weeks to months before
the onset of objective neurologic findings in
the arm. Typically, the pain was in the shoulder,
upper arm and elbo~; with radiation into the
fourth and fifth fingers. Dysesthesias included
a burning sensation in the fourth and fifth fingers
and freezing sensations in the arm. With
progression of the disease, the intensity of pain
progressed; at the time of diagnosis, 98% of
patients, complained of severe pain. In those
with progressive neurologic dysfunction, persistent
pain developed, prior to institution of
anticancer therap): These patients must be distinguished
from those previously irradiated
who then develop neurologic signs due to radiation
fibrosis of the braclfial plexus. Pain.is
.much less prominent in this syndrome; about
18% complain of pain, and only about 35% of
these patients ever develop severe pain. When
pain occurs, it is usually described as aching in
tile shoulder and tightness and heaviness in the
arm. This group of patients has a high incidence
of lymphedema (about 80%), while
patients with tumor infiltration have a rather
low prevalence of this complication.
Pain syndromes related to cancer therapy
include those complicating surgery, radiotherap);
and chemotherap): As noted, these
may occur in the absence of an active tumor
diagnosis and are therefore often associated
with different sets of psychological concomitants
than pain syndromes related to tumor
infiltration.
Thepost-surgical pain syndromes, including
post-thoracotomy, post-mastectom); post-radical
neck, and phantom limb pain, all share
injury to peripheral nerve. Tile typical pain is
characterized by pulling and burning dysesthesias
often with associated lancinating pains.
Post-mastectomy pain can appear immediately
after surgery or up to two to three months
later. It follows any type of mastectom); from
lumpectomy to radical rnastectomy It is more
prevalent in patients with postoperative complications,
such as excessive serous drainage or
local abscess. Pain is localized to tile posterior
arm, axilla and anterior chest wall. Patients
describe a constricting, burning pain, a “hot
poker” in the axilla, which is markedly exacerbated
by movement. Some of the patients
develop a shoulder-hand syndrome. Six to ten
percent of women undergoing surgical procedures
on the breast develop this syndrome, and
the symptoms do not improve with breast
reconstruction. The cause of this pain syndrome
is interruption of the intercostobrachial
nerve, which penetrates the anterior chest wall
and is severed in any surgic,’il procedure on the
breast. As such, post-mastectomy pain is not a
harbinger of recurrent disease.
Post-thoracotomy pain may occur following
surgical procedures on the lung. It is characterized
by burning in the area of the scar,
depressed sensation, and local changes in autonomic
function. Frozen shoulder and respiratory
splinting may also complicate the pain. In
contrast to those with post-mastect0my-syndrome,
patients whose pain worsens following
surgery are at high risk for recurrence of
disease.
Injury to the nerves involving tile cervical
and post-auricular areas may cause characteristic
lancinating pain in patients following radical,,
neck surger): This pain syndrome may
improve with anticonvulsant therap); such as
carbamazepine.
Another group of pain syndromes in
patients with cancer follows chemotherapy
(See Table 4). For example, the peripheral neur”opathy that occurs from the vinca alkaloids
may be characterized by continuous dysesthesias.
This syndrome eventually improves in
most patients and many benefit from temporary
use of tricTclic antidepressants, sometimes
supplemented by narcotic analgesics and intensive
physical therap): The pain associated with
aseptic necrosis of the femoral head may be
dramatically reversed by replacement of the
femoral head. Steroid pseudorheumatism is
diffuse aching pain associated with rapid withdrawal
of steroids; this pain may be dramatically
reversed by reinstitution of steroids. Postherpetic
neuralgia is a common and
distressing pain syndrome. Afflicted patients
should be treated early and aggressively with a
muhimodal approach including physical therap);
tricyclic antidepressants, transcutaneous
electrical nerve stimulation, and potentiall);
sympathetic blocks.
The incidence of post-radiation syndromes
is increasing with the number of longoterm survivors
of cancer therapy. Radiation fibrosis of
the brachial or lumbar plexus is not often associated
with severe p~n. More characteristic is a
large edematous limb that may not function
well. As always, the differential diagnosis from
tumor has to be made. About 20% of patients
with radiation myelopathy will present with a
central pain syndrome. The pain is characteristically
in the mid-back, occasionally with dysesthetic
sensations in the leg. This pain may
respond to steroids, anticonvulsant drugs or
the tricyclic antidepressants. Radiationinduced
second primary tumors and radiation
necrosis of bone represent other types of
potentially painful post-radiation syndromes.
Both malignant schwannomas and new primary
lung tumors have been reported to
develop at the site of earlier radiotherapy. A
patient with pain recurrence following radiotherapy
must therefore undergo reassessment
of the site to rule out the presence of a new
primary.
Finall); patients may be afflicted with pain
syndromes not associated with cancer or cancer
therapy. For example, osteoporotic collapse
. of a vertebral body may develop intercurrently
with cancer in the elderly bedridden patient
receiving steroid therap): The challenge in
these patients lies in distinguishing malignant
pain from that originating from non-neoplastic
processes.
In summau; there is a wide variety of pain
syndromes, knowledge of which is essential for
the appropriate evaluation and treatment of
cancer pain. Patients need to be assessed carefully
even in the setting of far-advanced disease.
The major goal is to understand the nature of
pain, the type of patient experiencing it, and
the implications for the course and prognosis
of the illness.