How pain management is the neverending clinical challenge

Half of patients undergoing active cancer treatment and up to 90% of patients with advanced or metastatic cancer, report moderate to severe pain.^1,2 “These statistics are well documented in numerous epidemiologic studies both in the United States and around the world,” notes Christine Miaskowski, PhD, RN, FAAN.¹ “What is often not considered is that these statistics have not changed in the past 30 years.”

Despite the promulgation of cancer pain management guidelines by the National Comprehensive Cancer Network, American Cancer Society, American Pain Society, and other professional bodies, half of cancer outpatients experience unrelieved pain. That rate is not acceptable in an era of evidence-based practice, notes Miaskowski.^1,3

As the baby-boomer generation ages and cancer survival times improve, increasing numbers of patients will be affected by cancer pain.⁴ Some authors have described pain as a neglected fifth vital sign for cancer patients.⁵ Patients with advanced or metastatic colorectal, gynecologic, prostate, and head and neck cancers tend to report greater pain severity than patients with other cancers.⁴

PAIN CLASSIFICATIONS

Baseline or chronic cancer pain can result from tumors, such as bone metastases, or from anticancer therapies, such as chemotherapy-associated peripheral neuropathy or secondary lymphedema following radiotherapy or lymph node dissection.

Breakthrough cancer pain is defined as transient exacerbations or intensifications of pain severity despite otherwise effective control of baseline pain. It frequently represents an even more daunting clinical challenge than chronic pain.^6,7 Breakthrough cancer pain is one of the most prevalent and formidable symptoms cancer patients face. It is associated with increased risks of patient anxiety and depression, reduced physical activity, disrupted sleep and social relationships, and reduced patient satisfaction with health care and quality of life.^6,8 Despite its potentially profound impact on patients’ well-being, however, there is relatively little consensus about assessment or optimal treatment of breakthrough cancer pain.^6,7

A GLOSSARY OF PAIN TYPES

Breakthrough cancer pain was not even widely recognized or studied before the 1990s.⁷ No single classification for breakthrough cancer pain is widely accepted, but a 2010 systematic review found most classification systems describe three broad types of breakthrough pain.⁷

Incident pain A predictable pain triggered by specific events (eg, standing or moving) that may be managed with short-acting opioids taken before a triggering event is attempted or is anticipated.^3,7

End-of-dose pain Rebound or recurrent pain experienced toward the end of the interval for regularly scheduled opioid doses, can be potentially managed by increasing the dose or frequency of opioid doses.^3,7 This type of pain seems to straddle between breakthrough pain and inadequately managed chronic pain. End-of-dose pain is addressed, when it occurs, by assessing the optimization of the analgesia schedule.⁸

Spontaneous or idiopathic pain Unanticipated or unpredictable pain not clearly tied to a known trigger.^3,7