title: Cancer Recurrence and Regional Anesthesia: The Theories, the Data, and the Future in Outcomes.
abstract: OBJECTIVE
  More than one million people each year in the United States are diagnosed with cancer. Surgery is considered curative, but the perioperative phase represents a vulnerable period for residual disease to spread. Regional anesthesia has been proposed to reduce the incidence of recurrence by attenuating the sympathetic nervous system's response during surgery, reducing opioid requirements thus diminishing their immunosuppressant effects, and providing antitumor and anti-inflammatory effects directly through systemic local anesthetic action. In this article, we present a description of the perioperative period, a summary of the proposed hypotheses and available literature on the effects of regional anesthesia on cancer recurrence, and put regional anesthesia in context in regard to its potential role in reducing cancer recurrence during the perioperative period.
  
  
  METHODS
  A literature review was conducted through PubMed by examining the following topics: effects of surgery on tumor progression, roles of multiple perioperative variables (analgesics, hypothermia, blood transfusion, beta-blockade) in cancer recurrence, and available in vitro, animal, and human studies regarding the effects of regional anesthesia on cancer recurrence.
  
  
  RESULTS
  in vitro, animal and human retrospective studies suppport the hypothesis that in certain types of cancer, regional anesthesia may be associated with lower recurrence rates. A few well-planned human randomized clinical trials are currently under way that may provide more solid evidence to substantiate or refute the benefits of regional anesthesia in reducing cancer recurrence.
  
  
  CONCLUSIONS
  The benefits of regional anesthesia in reducing cancer recurrence have a sound theoretical basis and, in certain cancers, are supported by the existing body of literature. This article outlines the current state of our knowledge on the relationship between cancer progression and regional analgesia.
authors.affiliation: *Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida, USA lle@anest.ufl.edu.
authors.forename: Linda
authors.initials: L
authors.lastname: Le-Wendling
authors.affiliation: *Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida, USA.
authors.forename: Olga
authors.initials: O
authors.lastname: Nin
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Lapeyronie University Hospital, Montpellier, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Capdevila
mesh_terms: D000765:Anesthesia, Conduction / Q000379:methods; D000818:Animals; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*
keywords: Anesthesia; Animal Studies; Cancer; Cancer Recurrence; Human Studies; Local Anesthetics; Opioids; Regional Anesthesia; Stress Response