Effect of perioperative regional anesthesia on cancer recurrence: A meta-analysis of randomized controlled trials

Background: Studies have reported that general anesthesia (GA), especially volatile agents were associated with higher cancer recurrence rate after cancer resection surgery. However, the effect of supplementary regional anesthesia (RA) in reducing the use of anesthetic agents on oncological outcomes remains unclear. The primary aim of this meta-analysis was to examine the effect of adjunctive use of RA on the cancer recurrence rate in adults undergoing cancer resection surgery. Methods: MEDLINE, EMBASE and CENTRAL were systematically searched for randomized control trials (RCTs) from its inception until April 2020. Results: Six RCTs (n = 3139 patients) were included. In comparison to the GA alone, our meta-analysis demonstrated no significant difference in the cancer recurrence rate in patients who received the adjunctive use of RA in the routine care of GA (3 studies, n = 2380 patients; odds ratio 0.93, 95%CI 0.63-1.39, p = 0.73, certainty of evidence = very low). Our review also showed no significant difference in cancer-related mortality (2 studies, n = 545; odds ratio 1.20, 95%CI 0.83-1.74, p = 0.33, certainty of evidence = low), all-cause mortality (3 studies, n = 2653; odds ratio 0.98, 95%CI 0.69-1.39, p = 0.89, certainty of evidence = low) and duration of cancer-free survival (2 studies, n = 659; mean difference 0.00 years, 95%CI -0.25-0.25, p = 1.00, certainty of evidence = high). Conclusion: This meta-analysis concluded that the adjunctive use of RA in the routine care of GA did not reduce cancer recurrence rate in cancer resection surgery. However, this finding needs to be interpreted with caution due to low level of evidence, substantial heterogeneity and potential risk of bias across the included studies.