Background: Neuropathic pain (NeP) is a burdensome problem in all stages of cancer.
Although clinical judgment is accepted as a surrogate for an objective gold standard in
diagnosing NeP, no publications were found about its reliability.
Objectives: Therefore, levels of agreement on the clinical examination of NeP were
estimated by calculating kappa-value (Κ) and percentage of pair wise agreement (PA) to
determine the interobserver reliability of diagnosing NeP.
Setting: The outpatient clinic of medical oncology of the Radboud University Nijmegen
Medical Centre.
Methods: Patients with cancer with potential NeP complaints were recruited from the
outpatient clinic of medical oncology. Physicians were recruited from the department of
pain and palliative medicine. Physicians and patients were recruited for participation in an
observational study in daily practice. Each patient (N = 34) was examined by 2 specialists
via independent clinical assessment. All consultations were video recorded. After each
assessment, physicians were asked to indicate the most adequate characterization of the
pain: pure NeP, pure nociceptive pain (NoP), mixed pain (MiP), or no pain (NP).
Results: Kappa (Κ) for the diagnosis of the most adequate pain characterization was 0.50,
PA 64.7%. For diagnosing pure NeP k was 0.78 (PA 91.2%), for the NeP component (NeP
+ MiP) and NoP component (NoP + MiP), it was respectively 0.52 (PA 76.5%) and 0.61 (PA
82.4%). For the diagnosis on the basis of the grading system between physicians, Κ was
0.34 (PA 52.9%). The intrarater reliability for the diagnosis of an NeP component on the basis
of clinical assessment and the NeP component on the basis of the grading system, for pain
specialists Κ was 0.69 (PA 85.3%) and for palliative care specialists Κ was 0.61 (PA 79.4%).
Limitations: The values of Κ and the PA for the existence of an NeP component are not
satisfying and the clinical agreement between physicians around findings from physical
examination should encourage a better standardization of the clinical assessment and
classification of pain in patients with cancer in respect with the identification of NeP.
Conclusions: A substantial level of agreement was found for the diagnosis of pure NeP and
a moderate level of agreement for the diagnosis of the NeP component was found, both with
a PA ≥ 70%. There was only a fair agreement between the physicians regarding the grading
system. However, there was a substantial level of (interrater) agreement for the diagnosis of
an NeP component and the outcome of the grading system. The findings in this study also
suggest that a better standardization of the clinical assessment and classification of pain in
patients with cancer with respect to the identification of neuropathic pain is necessary.
Key words: Neuropathic pain, diagnosis, interobserver reliability, agreement, cancer
observational study, pain, clinical assessment, diagnostic test
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