The Effect of Epidural Anesthesia on Oncologic Outcomes After Surgery for Colon and Rectal Cancer

Background: Surgical trauma induces a physiologic stress response that is well documented in the literature The surgical stress response comprises alterations in the endocrine, metabolic, inflammatory and immune systems with important clinical ramifications on patient morbidity and recovery in the post-operative period. Consequences have been identified in multiple organ systems. Emphasis has therefore been placed on the identification of practices and techniques that may reduce the invasiveness of the surgical procedure and hence the resultant deleterious surgical stress response. Minimally invasive surgery, i.e. laparoscopy, is one innovation that has been shown to reduce postoperative immunosuppression when compared to conventional surgical approaches in colon surgery (Ordemann, 2001). In a similar manner, epidural anesthesia has been shown to have an impact on the stress response and post-operative morbidity. The neural blockade provided by epidural anesthesia has been demonstrated to reduce intra-operative blood loss, postoperative MI, wound infection, DVT and PE by as much as 30% The relationship of the stress response to oncologic-specific outcomes has not been well defined in the literature. Attenuation of the tumor-promoting effect of surgery by spinal blockade has been studied in rats. Bar-Yosef et al (2001) utilized a rat model to study the impact of adjunctive spinal anesthesia on cancer metastases after laparotomy. The study reported a 70% reduction in the lung tumor retention (i.e., metastases) when spinal blockade was added to general anesthesia during laparotomy. The pursuit of clinical practices that reduce the stress response with resultant improvement in long-term oncologic outcomes has important potential clinical implications.