Neuropathic pain in cancer: systematic review, performance of screening tools and analysis of symptom profiles

Background: The objectives of this study were to evaluate the methodological quality of rigorous neuropathic pain assessment tools in applicable clinical studies, and determine the performance of screening tools for identifying neuropathic pain in patients with cancer. Methods: Systematic literature search identified studies reporting use of Leeds Assessment of Neuropathic Symptoms and Signs (LANSS), Douleur Neuropathique en 4 (DN4) or painDETECT (PDQ) in cancer patients with a clinical diagnosis of neuropathic or not neuropathic pain. Individual patient data were requested to examine descriptor item profiles. Results: Six studies recruited a total of 2301 cancer patients of which 1564 (68%) reported pain. Overall accuracy of screening tools ranged from 73 to 94%. There was variation in description and rigour of clinical assessment, particularly related to the rigour of clinical judgement of pain as the reference standard. Individual data from 1351 patients showed large variation in the selection of neuropathic pain descriptor items by cancer patients with neuropathic pain. LANSS and DN4 items characterized a significantly different neuropathic pain symptom profile from non-neuropathic pain in both tumour- and treatment-related cancer pain aetiologies. Conclusion: We identified concordance between the clinician diagnosis and screening tool outcomes for LANSS, DN4 and PDQ in patients with cancer pain. Shortcomings in relation to standardized clinician assessment are likely to account for variation in screening tool sensitivity, which should include the use of the neuropathic pain grading system. Further research is needed to standardize and improve clinical assessment in patients with cancer pain. Until the standardization of clinical diagnosis for neuropathic cancer pain has been validated, screening tools offer a practical approach to identify potential cases of neuropathic cancer pain.