Local Anesthetics and Recurrence after Cancer Surgery-What's New? A Narrative Review

Abstract

The perioperative use of regional anesthesia and local anesthetics is part of almost every anesthesiologist's daily clinical practice. Retrospective analyses and results from experimental studies pointed towards a potential beneficial effect of the local anesthetics regarding outcome-i.e., overall and/or recurrence-free survival-in patients undergoing cancer surgery. The perioperative period, where the anesthesiologist is responsible for the patients, might be crucial for the further course of the disease, as circulating tumor cells (shed from the primary tumor into the patient's bloodstream) might form new micro-metastases independent of complete tumor removal. Due to their strong anti-inflammatory properties, local anesthetics might have a certain impact on these circulating tumor cells, either via direct or indirect measures, for example via blunting the inflammatory stress response as induced by the surgical stimulus. This narrative review highlights the foundation of these principles, features recent experimental and clinical data and provides an outlook regarding current and potential future research activities.

Keywords: cancer; inflammation; local anesthetics; metastasis; recurrence.

Figure 1

Schematic illustration of metastasis formation by circulating tumor cell. CTC = circulating tumor cells; EMT = epithelial-to-mesenchymal transition; MET = mesenchymal-to-epithelial transition [20].

Figure 2

Schematic illustration of processes leading to perioperative inflammation and immune suppression (surgical stress response) and possible inhibition by local anesthetics (shown as ⟂). LA = local anesthetics; IL = interleukin; TNFα = tumor necrosis factor α; ICAM-1 = intercellular adhesion molecule 1; MHC = major histocompatability complex; NK cell = natural killer cell. Modified after [46].