Cancer pain management – opportunities beyond the WHO ladder

Abstract

Cancer-related pain remains a signifi cant clinical problem despite continuing advances in both antineoplastic therapy and supportive medicine. Th e optimal clinical management of pain can be subdivided into 3 phases:1. Realisation of the problem by the attending medical staff , including diff erential classifi cation of the individual pain syndrome, and, importantly, its quantifi cation. 2. Choice of the most appropriate treatment modality, or a combination of multiple treatment modalities. 3. Assessment of response to the analgesic regimen, and, if required, modifi cation of the pain management.Th e fi rst and the third of these phases will be briefl y addressed in this editorial, while three short reviews in this issue of memo will focus on particular treatment modalities, which, in addition to the basic analgesic regimen, should always be considered for patients with cancer pain.Undertreatment of cancer-related pain is not a subjective issue of a few, unlucky individuals, but is a frequent and well-documented problem, as indicated by a growing number of publications. A systematic review by Van den Beuken-van Everdingen and co-workers [1], covering literature of the past 4 decades, revealed an average cancer pain prevalence of 53% with a range from 33% in patients on curative treatment up to 64% in terminally ill patients with advanced, metastatic disease. Importantly, nearly half of the latter cohort suff ers from moderate or severe pain. Stratifi cation of the included studies by cancer type did not reveal huge diff erences, with head-andneck cancers leading the table with a pain incidence of 70%.A widely applied measure of the adequacy of pain management is the so-called pain management index (PMI) as proposed by Zelan, Ward and Cleeland [2,3]. Th e PMI is defi ned as the numerical diff erence between the intensity of pain treatment (rated 0 to 3, according to the WHO scale) and the original pain intensity according to the Brief Pain Inventory, categorised as 0 (no pain), 1 (1-3, mild pain), 2 (4-7, moderate pain), or 3 (8-10, severe pain). A PMI of zero or higher indicates adequate -or overtreatment, while a negative PMI defi nes undertreatment. Deandrea and colleagues recently conducted a systematic review of 26 studies including between 39 and 905 patients, respectively, published between 1994 and 2007, which assessed the PMI in cancer patients [4]. Th ey report an average incidence of 43% for pain undertreatment with a wide inter-study range from 8 to 82%. Th e most frequently reported factors associated with undertreatment were early disease stage (no distant metastases), a good performance score, and discrepancy between the patient's and the physician's estimate of pain severity. Furthermore, undertreatment was reported more frequently in studies from Europe or Asia than in those from the USA, in studies from poorer countries, and in studies published before 2001. Undertreatment was signifi cantly less frequently reported from institutions specialised in cancer treatment.More recently, the results of ...