Local Anesthetics (LAs) and Cancer Cell Progression: Is There an Oncologic Protective Role for LAs in Clinical Practice?

The purpose of this article is to provide a brief review of current literature examining the potential oncologic protective role local anesthetics may provide in the perioperative setting during cancer surgery.

Paradoxically, curative surgery for cancer appears to favor the development of recurrences and distant metastasis. The accumulated knowledge about cancer biology and our understanding of the pathophysiological events occurring during the perioperative period have opened several theories on potential mechanisms for this century old observation. In such, cell-mediated immune response, the first line attack against cancer is suppressed during the perioperative period possibly providing circulating tumor cells with a fruitful environment allowing them to escape the immune system to form local recurrence and metastasis. In parallel, surgical stress, acute pain, and inflammatory cytokines released during surgery all directly or indirectly contribute to the immunosuppression state. Current data indicates that surgery itself cannot be regarded as the sole culprit for this paradox, and other factors during the perioperative period such as anesthetic drugs or anesthesia techniques are conceivably involved as well. As an example, volatile anesthetic seem to have negative effects while propofol appears to have protective effects. Opioids were also found to be immunosuppressive and therefore may not represent an ideal choice. Of the drugs used in anesthesia, local anesthetics seem to be the most attractive with regard to cancer surgery.

Depending on their mode of administration, local anesthetics have been found in several reports to directly or indirectly blunt the systemic response to surgery, preserve immune function, alter cytokine release, and interfere with cancer cell signaling pathways. They are also analgesic and have anti-inflammatory properties. The former and the latter are sought effects in the perioperative period. However, their impact on recurrence, overall survival and metastasis remains controversial.