Cancer-related neuropathic pain in out-patient oncology clinics: a European survey

Background: Although pain is frequently experienced by patients with cancer, it remains under-treated. The primary aim of this study was to estimate the prevalence of cancer-related neuropathic pain (CRNP) in patients with chronic pain who attended an outpatient clinic for standard care in Europe (irrespective of the reason or stage of the cancer). The secondary aims of this study were to characterise pain and cancer in patients with CRNP (including treatment) and to evaluate the usefulness of the painDETECT (PD-Q) screening tool to help physicians identify a potential neuropathic component of cancer-related pain. Methods: An observational, non-interventional, cross-sectional, multi-centre study of adult patients with cancer using patient and physician case report forms (CRFs). Patients with CRNP were identified by physicians' clinical assessments after examining the completed PD-Q. Results: A total of 951 patients visiting outpatient clinics across Europe were enrolled in this study between August 2010 and July 2011. Of these, 310 patients (32.60%; 95% confidence interval 29.62, 35.58) were identified as having CRNP. Twenty-nine of 39 (74.4%) physicians who completed the CRF relating to the PD-Q considered it a useful tool to help detect CRNP in daily practice and 28 of 39 (71.8%) indicated that they would use this tool in the future for most or some of their patients. Data from physicians before and after review of the completed PD-Qs showed a shift in clinical opinion (either to positive CRNP diagnosis [yes] or negative CRNP diagnosis [no]) in respect of 142 patients; about half of which (74) were categorised with an initial diagnosis of unknown. Opinions also shifted from a no to a yes diagnosis in 10 patients and from a yes to a no diagnosis in 51 patients. Conclusions: Approximately one-third of adults with cancer experiencing chronic pain attending outpatient clinics as part of routine care were considered to have CRNP in the opinion of the physicians after considering scores on the PD-Q. While physicians did not consider the PD-Q to be a useful tool for all patients, shifts in diagnosis before and after the use of this tool indicate that it may help physicians identify CRNP, especially where there is initial uncertainty.