title: Should the rate of opioid dose escalation be included as a feature in a cancer pain classification system?
abstract: The purpose of this study was to assess the need for opioid dose escalation as a feature of a pain classification system for advanced cancer patients. Opioid dose escalation was included as a prognostic feature in the original Edmonton Staging System (ESS) for pain classification, but was not included among the five features of the revised ESS (rESS): pain mechanism, incident pain, psychological distress, addictive behavior, and cognitive function. Mercadante et al.'s definition of opioid escalation index percentage (OEI%) has been used as a surrogate marker for opioid responsiveness. Our hypothesis was that younger age (<60 years), neuropathic pain, incident pain, psychological distress, and addictive behavior would be associated with an OEI% >5%. Using data from a recent multicenter validation study of the rESS, a secondary analysis of a subsample of 532 advanced cancer patients with a pain syndrome was conducted. Approximately 44% (n=232) of the patients had an OEI% >5%. There were no significant associations between OEI% and age, neuropathic pain, incident pain, psychological distress, or addictive behavior. As originally proposed as a clinical marker, the OEI% may oversimplify the complexity of pain management in advanced cancer patients. Future studies are required to better elucidate the need for opioid dose escalation as a feature of a cancer pain classification system.
authors.affiliation: Department of Oncology, University of Alberta, Edmonton, Alberta, Canada. slowe@ualberta.ca
authors.forename: Sonya S
authors.initials: SS
authors.lastname: Lowe
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Nekolaichuk
authors.forename: Robin L
authors.initials: RL
authors.lastname: Fainsinger
authors.forename: Peter G
authors.initials: PG
authors.lastname: Lawlor
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000145:classification* / Q000150:complications; D010146:Pain / Q000145:classification* / Q000188:drug therapy* / Q000209:etiology; D012189:Retrospective Studies; D012959:Socioeconomic Factors
chemical_list: D000701:Analgesics, Opioid