The impact of anesthetic techniques on survival for patients with colorectal cancer: evidence based on six studies.

Background/aims: Epidural-supplemented general anesthesia is perceived as a more beneficial method over general anesthesia since it reduces incidence of side effects, provides better postoperative pain relief and lowers the possibility to use immunosuppressive anesthetics. However, previous prospective and retrospective studies reported conflicting results in the effects of epidural anesthesia on post-operative outcomes of colorectal cancer surgery. Therefore, this study aims to pool available evidence to assess the association between epidural anesthesia and the post- operative outcomes in this group of patients.

Methodology: Relevant studies were searched in databases and a meta-analysis was performed to estimate the association between epidural anesthesia and overall survival and recurrence free survival.

Results: Compared with the anesthetic choice without epidural anesthesia, epidural-supplemented anesthesia is associated with significantly longer overall survival (HR: 0.72, 95% CI: 0.55-0.94, p = 0.01) but not with prolonged recurrence free survival (HR: 1.06, 95% CI: 0.96-1.16, p = 0.23). These results showed a highlevel of robustness in sensitive test.

Conclusion: Although epidural anesthesia might not lead to improved recurrence free survival, it had significant benefit in improving overall survival and reducing all-cause of death. It might be a useful anesthetic technique for colorectal cancer patients undergoing surgery. However, prospective studies are required to confirm whether this benefit is causative with epidural anesthesia.