As a result of a burgeoning science and an
intensive educational campaign that began more than a decade ago,
oncologists now appreciate that pain is an extremely common
comorbidity of cancer. Chronic pain, which is usually caused by
the tumor itself, is experienced by 30% to 50% of patients with
varied solid tumors who are in the intermediate stages of the disease
and are usually undergoing active antineoplastic therapy. When
populations with advanced disease are specifically evaluated,
particularly those with limited options for further disease-modifying
therapies, the prevalence can be as high as 75% to 90%.
There is a compelling need for effective management of cancer pain.
Pain is profoundly frightening to patients. It is associated with
impaired quality of life, and pain severity is linked to declining
performance status and poor psychosocial functioning. Even mild
pain is associated with a diminished ability to enjoy life.
Fortunately, the available therapies for pain have good efficacy and
can help most patients maintain a satisfactory degree of pain
control. There is a broad consensus that opioid-based pharmacotherapy
should be the mainstay approach and there is credible evidence that
most patients respond well to simple and conservative interventions
that involve the long-term administration of an oral or transdermal
opioid. The possibility that effective pain control can be
attained by cancer patients who receive optimal systemic therapy is
very good news for patients and those who care for them.
This statistic, however, must be qualified. A high likelihood of
therapeutic success is only achieved if opioid therapy is
administered optimally, applying well known guidelines aggressively
over time. These guidelines stress the need for repeated
assessment, appropriate selection of a specific drug and starting
dose, ongoing dose adjustment, treatment of side effects, and the use
of coanalgesic drugs and other interventions (including
antineoplastic interventions when appropriate). Sadly, there is
strong evidence that this optimal approach often is not applied.
Large surveys suggest that approximately 40% of ambulatory cancer
patients, and as many as 80% of elderly cancer patients in
long-term care facilities receive inadequate treatment for their
pain. Clearly, oncologists must continue to work diligently to
reverse the undertreatment of pain.
The reassuring outcome of optimal pain therapy also should not
obscure the reality that 10% or more of cancer patients with chronic
pain may not achieve adequate pain control despite optimally
administered systemic opioid therapy. These patients need a level of
aggressive pain management that may be beyond the knowledge and
skills of the practicing oncologist. Oncologists must recognize and
refer them for other analgesic approaches when needed.
A broad range of alternative interventions can be considered for the
patient with refractory pain. To advise patients and provide access
to the best care for challenging cases, oncologists must be aware of
these treatments and knowledgeable about patient selection criteria,
risks, and potential benefits.
One important group of interventions for patients with refractory
cancer pain involves intraspinal drug infusion. After more than 20
years experience with the use of spinally administered drugs for pain
control, there is now wide acceptance of the approach for a carefully
selected group of patients. Intraspinal infusion is typically
implemented by an anesthesiologist with expertise in pain management.
A variety of specific techniques and drug combinations are available.
Although there are yet few controlled clinical trials of these
interventions, there is sufficient experience for informed
decision-making by knowledgeable clinicians.
This Desk Reference of Oncology presents a series of articles from a
roundtable discussion focused on the role of intraspinal infusion for
cancer pain. The need to redress undertreatment is the subtext for
these presentations, and the specific objective is to provide a solid
background of information about spinal therapy for the practicing
oncologist. When pain persists despite optimal conservative
management, the oncologist should be prepared to evaluate the
appropriateness of intraspinal techniques, explain these to the
patient, refer as needed, and help monitor the patient after therapy.
The articles that follow hopefully provide the information necessary
to advance this goal.
1. Bonica JJ, Ventafridda V, Twycross RG: Cancer Pain. In Bonica JJ, ed: The Management of Pain, 2nd
Ed. Philadelphia: Lea & Febiger,
1990, pp 400-460.
2. Serlin RC, Mendoza TR, Nakamura Y, et al: When is cancer pain
mild, moderate or severe? Grading pain severity by its interference
with function. Pain 61:277-284, 1995.
3. Zech DFJ, Grond S, Lynch J, et al: Validation of World Health
Organization guidelines for cancer pain relief: A 10-year prospective
study. Pain 63:65-76, 1995.
4. Jacox A, Carr DB, Payne R, et al: Management of cancer pain,
clinical practice guidelines, No. 9, AHCPR Publication No. 94-0592.
Rockville, MD: U.S. Department of Health and Human Services, Public
Health Service, Agency for Health Care Policy and Research, 1994.
5. Cleeland CS, Gonin R, Hatfield AK, et al: Pain and its treatment
in outpatients with metastatic cancer. N Engl J Med 330:592-596, 1994.
6. Benrubi R, Gambassi G, Lapane K, et al: Management of pain in
elderly patients with cancer. J Amer Med Assoc 279:1877-1882, 1998.