Managing Pain in Patients With Advanced Cancer: The Role of Neuraxial Infusion

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.[1] 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.[2] 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.[3] 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.[4] 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,[5] and as many as 80% of elderly cancer patients in long-term care facilities[6] 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.

References:

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.