Treatment for neuropathic pain in patients with cancer: comparative analysis of recommendations in national clinical practice guidelines from European countries.

INTRODUCTION: Neuropathic pain is a common symptom, present in 39% of the patients with cancer pain. Treating this type of pain is challenging, as this patient group is often frail and has comorbidities which increase the risk of side events and hence influences their quality of life. Clinical practice guidelines (CPGs) can be helpful for clinicians, especially when scientific evidence is uncertain or weak. In this study, we focused on the quality of the review of the literature used in treatment recommendations in the selected European CPGs.
METHODS: In a previous study, 9 CPGs from European countries that contained at least one paragraph on treatment for neuropathic pain in cancer were included. Recommendations with their grade (according SIGN 55 classification) and supporting literature (first author, patients' population, year and type of publication) were compared between CPGs.
RESULTS: In all CPGs, amitriptylin was mentioned as the drug of first choice. Six guidelines proposed also gabapentinoids. Only 30 of the 163 citations (18%) were based on studies in patients with cancer. Seven CPGs did not argue the indirect evidence due to extrapolation of study results from non-cancer to patients with cancer.
CONCLUSION: The majority of guideline development groups extrapolated their results from non-cancer publications to formulate recommendations. Consequently, these guidelines fail to address important issues such as altered kinetics and side effect profiles in these patients. We recommend creating specific recommendations by an international expert group for the treatment for neuropathic pain in patients with cancer supported by targeted research in patients with cancer.