A case report of sustained resolution of cancer pain by continuous perineural infusion of local anaesthetic.

Abstract

Opioids are currently offered as first-line treatment for chronic pain from cancer. Continuous regional analgesia could be an alternative to opioids. However, the required duration of catheterization and the sustained analgesic effects of this technique after catheter removal have yet to be clarified. We report the case of a patient with a shoulder desmoid tumour for which monitoring of tumour progression was the sole therapeutic strategy. Analgesia took the form of patient-controlled infusion of local anaesthetics through an interscalene catheter. Due to the need of an MRI control 45days later, the pump was stopped. The persistence of pain relief 48hr later led to the decision to remove the perineural catheter. No pain was reported by the patient over the following 42days. In this patient, it would seem that continuous analgesia allowed for a sustained resolution of pain from the shoulder-located tumour. One hypothesis is that local anaesthetics play a direct role in the erasure of pain memory. This hypothesis needs to be tested with a large patient cohort. This case report provides new insights into the treatment of cancer pain. The most interesting finding is that the pain did remained absent after 45days of continuous infusion of local anaesthetics through an interscalene catheter. We postulated that local anaesthetic drugs have an impact on pain memory.