APS unveils guideline for treatment of cancer pain

New evidence-based guidelines for the treatment of cancer pain were presented at the 24th Annual Scientific Meeting of the American Pain Society (APS) in Boston last month. The meeting was designed to help clinicians and patients better control the pain associated with the disease. According to APS, approximately 1.2 million people are diagnosed with cancer each year. While effective treatment for pain exists, studies have reported significant undertreatment.

"Undertreatment of cancer pain causes mood disturbances and needless suffering, impairs the ability to function, hampers quality of life, and increases the burden on family caregivers," said Christine Miaskowski, R.N., Ph.D., professor and chair, department of nursing, University of California San Francisco and co-chair of the APS cancer guideline panel. APS estimates that 17% to 57% of adults and 25% to 85% of children receiving treatment for cancer have pain.

The APS Guideline for the Management of Cancer Pain in Adults and Children was developed by an interdisciplinary panel of 13 cancer pain experts. It updates and revises an earlier guideline published in 1994 by the U.S. Agency for Healthcare Policy & Research (now the Agency for Healthcare Research & Quality).

APS recommends that, while waiting for an assessment and diagnostic workup, cancer patients should be given a prescription for an analgesic medication, such as hydrocodone with acetaminophen or oxycodone with acetaminophen. They should be instructed to fill the Rx and use the medication for unexpected pain that warrants prompt treatment, followed by a call to their healthcare provider for evaluation of the problem.

Initial treatment should be based on the severity of pain the patient reports, according to the guidelines, followed by the use of algorithms, based on worst-pain-intensity ratings using a 0 to 10 numeric rating scale, to determine appropriate treatment. Generally, mild pain is relieved with a nonopioid analgesic or a combination of a nonopioid and an opioid analgesic. Moderate to severe pain usually requires the use of an opioid.

When warranted, patients should be started on a long-acting opioid on an around-the-clock basis. Once the patient's pain intensity and dose are stabilized, an immediate-release opioid can be used on an as-needed basis for breakthrough pain. Opioid doses should be adjusted for each patient to achieve pain relief with an acceptable level of side effects.

"Meperidine should not be used in the management of chronic cancer due to its short duration of action and its toxic metabolite, normeperidine," noted Rebecca S. Finley, Pharm.D., M.S., FASHP, president of Meniscus Educational Institute and a member of the panel that developed the guidelines. "In patients who require repeated high doses, accumulation of the metabolite has been associated with neurotoxicity, including seizures, agitation, tremors, and myoclonus." Intramuscular administration of drugs should also be avoided, according to APS, because the route can be painful, inconvenient, and absorption is not reliable.

"Pharmacists and other healthcare professionals should ensure that patients and their families are aware of the most common side effects and how they may be manifested," Finley noted. "It is important to correlate the incidence and severity of side effects with the degree of pain relief because the use of opioids is often viewed as titrating between relief of pain and an acceptable level of side effects." Most patients can achieve a level of significant pain relief with minimal adverse effects, she added.

All patients who are started on an opioid analgesic should also begin a bowel regimen to prevent constipation, a significant side effect that can interfere with a patient's adherence to the analgesic regimen. The guidelines also recommend monitoring for and prophylactically treating other opioid- induced side effects as well. Antiemetics should be prescribed in anticipation of nausea and vomiting.