Efficacy of lidocaine in patients receiving palliative care with opioid-refractory cancer pain with a neuropathic component: study protocol for a randomized controlled study
BACKGROUND
The management of patients suffering from opioid-refractory cancer pain with a neuropathic component remains an important challenge for healthcare workers. Only one retrospective study specifically reported the use of intravenous (IV) lidocaine amongst the palliative care unit population, the study found that there was a positive response to this therapy. These preliminary uncontrolled results need to be confirmed by randomized controlled trials. The primary objective of this study is to assess the analgesic efficacy of IV lidocaine in patients in palliative care suffering from opioid-refractory cancer pain with a neuropathic component. The secondary objectives are to assess the tolerance of, symptomatology, and patient satisfaction with the therapeutic approach.


METHODS/DESIGN
This will be a multicenter, prospective, randomized, placebo-controlled, double-blind, two-parallel group study. It will take place in eight adult palliative care units across France. The main inclusion criteria are as follows: adult patients suffering from opioid-refractory cancer pain with a neuropathic component, and those receiving palliative care as defined by French Society of Palliative and Support Care. Participants will be randomized (1:1 allocation ratio) to one of two treatment groups: a) lidocaine-experimental group (intravenous lidocaine), or b) placebo-control group (intravenous saline solution). Evaluation assessments will be taken at baseline (T0 randomization), 40 minutes (T1), 120 minutes (T2), 12 hours (T3), 24 hours (T4), 48 hours (T5), and 14 days (T6) after baseline. The primary endpoint is change in the pain level between T0 and T1. The secondary endpoints are: changes in the pain level between T0 and other times, intensity of the neuropathic pain component, daily opioid consumption, symptoms (as classified by the MD Anderson Symptom Inventory), adverse events, and patient's satisfaction (measured using the Pain Treatment Satisfaction Scale). A sample size of 200 individuals will be needed to obtain 90% power to detect a 25% difference in pain success at T1 between the two groups; pain success is classified as a 30% decrease in the pain level between T0 and T1 (10% of patients lost to follow-up expected).


DISCUSSION
The randomized, double-blind, placebo-controlled design is the most appropriate design to demonstrate the efficacy of a new experimental intervention (Evidence-Based Medicine Working Group classification). National and international recommendations could be updated based on the findings of this study.


TRIAL REGISTRATION
Current controlled trials NCT02137954 (registration date: 7 May 2014).