Effect of combined epidural-general anesthesia on long-term survival of patients with colorectal cancer: a meta-analysis of cohort studies.

Abstract

This study aimed to analyze the long-term survival of patients with colorectal cancer after receiving combined epidural-general anesthesia (EGA) or general anesthesia (GA) alone. The PubMed, MEDLINE, Web of Science, Cochrane Library, and Embase databases were used to search for cohort studies that explored the differences between the effects of EGA and GA on overall survival (OS) and recurrence-free survival (RFS) of patients with colorectal cancer. The hazard ratios (HRs) and their 95% confidence intervals (95%CIs) were used as indicators to evaluate the strength of the effects and were pooled. Nine studies were included in the meta-analysis. EGA improved the OS of patients with colorectal cancer compared with GA (HR = 0.904, 95%CI 0.871-0.938, P < 0.05). In the subgroup analysis, EGA was more protective for OS of patients with colon cancer than GA (HR = 0.840, 95%CI 0.732-0.963, P < 0.05), but not for OS of patients with rectal cancer (HR = 0.764, 95%CI 0.398-1.469, P > 0.05). Additionally, EGA could not further prolong RFS in patients with colorectal cancer (HR = 1.015, 95%CI 0.942-1.093, P > 0.05), which was the same in the subgroup analysis of patients with colon cancer (HR = 0.908, 95%CI 0.760-1.085, P > 0.05). EGA could improve the OS of patients with colorectal cancer, especially those with colon cancer, but it could not improve the OS in the subgroup of patients with rectal cancer. This difference may be due to the immune protective function of the parasympathetic nerve innervating the intestinal tubes above the splenic flexure retained by EGA. Additionally, although EGA has a protective effect on RFS in patients with colorectal cancer, the difference was not significant. The design of this analysis is registered and displayed in the PROSPERO database (CRD42021274864).